WO2017177960A1 - Electrolyte solution, battery, and battery pack - Google Patents

Electrolyte solution, battery, and battery pack Download PDF

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Publication number
WO2017177960A1
WO2017177960A1 PCT/CN2017/080546 CN2017080546W WO2017177960A1 WO 2017177960 A1 WO2017177960 A1 WO 2017177960A1 CN 2017080546 W CN2017080546 W CN 2017080546W WO 2017177960 A1 WO2017177960 A1 WO 2017177960A1
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Prior art keywords
positive electrode
ion
battery
graphene
electrolyte
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PCT/CN2017/080546
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French (fr)
Chinese (zh)
Inventor
陈璞
刘洋
朱晓
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苏州宝时得电动工具有限公司
陈璞
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Priority claimed from CN201610971595.4A external-priority patent/CN108063253A/en
Application filed by 苏州宝时得电动工具有限公司, 陈璞 filed Critical 苏州宝时得电动工具有限公司
Publication of WO2017177960A1 publication Critical patent/WO2017177960A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrolyte for a battery, and a battery using the same.
  • the lead-acid battery has been in existence for more than 100 years and has mature battery technology, occupying an absolute market share in the energy storage fields such as automobile starter batteries, electric bicycles and UPS.
  • the lead-acid battery has a low cycle life and a relatively low energy density, it has the advantages of very low price and very high cost performance. Therefore, in recent years, nickel-metal hydride batteries, lithium-ion batteries, sodium-sulfur batteries, and liquid flow batteries have failed to replace lead-acid batteries in the field of energy storage.
  • the positive electrode of the secondary battery is capable of reversible elution-embedding reaction based on metal ions
  • the negative electrode can perform reversible reduction deposition-oxidation dissolution reaction based on metal ions
  • the electrolyte contains metal ions participating in the positive electrode extraction-embedding reaction and participating in negative electrode deposition- Dissolve the reacted metal ions.
  • the electrolyte of this type of battery is an aqueous solution, and there is no safety hazard similar to the organic electrolyte in a lithium ion battery, and it is environmentally friendly, low in cost, and high in energy density. Therefore, this type of battery is very promising as a next-generation energy storage battery to replace lead-acid batteries, which has great application value.
  • the metal ion participating in the negative electrode deposition-dissolution reaction of the battery of the type may be zinc ion.
  • the negative electrode active material is metal zinc.
  • such negative electrode active material has problems such as dendrite, corrosion, hydrogen evolution and the like when charged and discharged in the aqueous solution, thereby The cycle performance and charge and discharge capacity of the battery are affected. Therefore, the prior art needs further improvement.
  • such a water-based secondary battery mainly uses LiMn 2 O 4 as a positive electrode active material, but its electrical conductivity is not satisfactory.
  • conductive carbon black is used as a conductive agent to increase the conductivity of the battery electrode.
  • the electrode is usually a mixture of an electrode active material, a conductive agent such as acetylene black, and a polymer binder.
  • carbon black nanoparticles show insufficient performance in remote conductivity, thereby limiting the rate performance of the battery.
  • Graphene is the thinnest and strongest material known at present, and has outstanding characteristics such as large specific surface area, excellent electrical and thermal conductivity, and low thermal expansion coefficient. Therefore, graphene has great application prospects in the field of energy storage, heat conduction and high-strength materials.
  • One of them is a conductive agent as a secondary battery.
  • the research and application of graphene puts forward a demand for its high-volume, low-cost preparation.
  • the preparation methods of graphene mainly include micro mechanical peeling method, graphite intercalation, reduced graphite oxide and vapor deposition. method.
  • Graphene prepared by micromechanical stripping method has many internal defects and poor quality.
  • the graphene prepared by chemical vapor deposition has higher quality, but most of the obtained graphite is two-dimensional flake graphite.
  • the interface resistance between the graphite flakes is not conducive to long-term electron transfer and fast transmission.
  • an object of the present invention is to provide an electrolyte which can be used for a battery, which can effectively suppress problems such as dendrites, corrosion, hydrogen evolution and the like of the negative electrode, particularly the zinc negative electrode.
  • the invention provides an electrolyte for a battery, which comprises a negative electrode metal ion which can be reduced and deposited as a metal in the negative electrode during charging and discharging and which can be reversibly oxidized and dissolved; a positive electrode ion which participates in a positive electrode reaction of the battery; and an additive ion,
  • the additive ion is selected from at least one of Na, Mg, Al, NH 4 + , Ni, Co, Ce, Fe, Pb or Mn ions, and the additive ion is different from the negative electrode metal ion and the positive electrode ion.
  • the concentration of the additive ions in the electrolyte is from 0.001 M to 8 M.
  • the concentration of the additive ion Mg ions in the electrolyte is from 0.001 M to 0.5 M.
  • the concentration of the additive ions Ce, Fe, Mn, Pb and/or Co ions in the electrolyte is from 0.1 M to 8 M.
  • the negative metal ion is a zinc ion.
  • the positive electrode ion is selected from the group consisting of lithium ion, sodium ion or magnesium ion.
  • the negative electrode metal ion is a zinc ion
  • the positive electrode ion is a bromide ion or a vanadium ion.
  • the electrolyte has a pH of 2-8.
  • the electrolyte further includes a solvent which is water and/or an alcohol.
  • the present invention also provides a battery comprising: a positive electrode, a negative electrode, and the electrolyte.
  • the positive electrode includes a positive electrode material
  • the positive electrode material includes a positive electrode active material and a positive electrode conductive agent
  • the positive electrode conductive agent is graphene
  • the graphene is composed of a single layer or a plurality of graphene structural units
  • Graphene has a pore-like structure with a pore size distribution ranging from 2 to 10 nm.
  • the graphene has an average pore diameter ranging from 3-5 nm.
  • the graphene has a size ranging from 200 to 1000 nm.
  • the graphene has a specific surface area of 300 to 2000 m 2 /g.
  • the present invention also provides a battery pack comprising a plurality of batteries as described above.
  • the cycle performance and the charge and discharge capacity of the battery are further improved. Further, the battery using the electrolytic solution of the present invention has a good capacity retention ratio, low discharge capacitance loss, and enables deep discharge.
  • the use of the new electrolyte can effectively suppress dendrites, corrosion, hydrogen evolution and the like of the negative electrode (for example, a zinc negative electrode).
  • the battery cycle performance was obtained, the charge and discharge capacity was improved, and it was unexpectedly found that deep discharge of the battery can be achieved.
  • the present invention also provides a graphene having a porous structure, which has good long-range conductor and ion-conducting properties.
  • the present invention provides a graphene composed of a single layer or a plurality of graphene structural units, the graphene having a pore-like structure with a pore size distribution ranging from 2 to 10 nm.
  • the graphene has an average pore diameter ranging from 3-5 nm.
  • the graphene has a size ranging from 200 to 1000 nm.
  • the specific surface area of the graphene 300-2000m 2 / g Preferably, the specific surface area of the graphene 300-2000m 2 / g.
  • the present invention also provides a positive electrode comprising a positive electrode material, the positive electrode material comprising a positive electrode active material and a positive electrode conductive agent, the positive electrode conductive agent comprising the graphene.
  • the present invention also provides a battery comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, the positive electrode including a positive electrode material, the positive electrode material including a positive electrode active material and a positive electrode conductive agent, the positive electrode
  • the conductive agent includes graphene as described above.
  • the positive electrode conductive agent accounts for 2%-15% by mass of the positive electrode material.
  • the positive electrode active material has a mass percentage in the positive electrode material ranging from 80 to 90%.
  • the positive active material is capable of reversibly extracting-embeding a first metal ion, the first metal ion being selected from lithium ions, sodium ions or magnesium ions; the electrolyte comprising an electrolyte and solvent water; Electrolyzing the first metal ion and the second metal ion; the first metal ion is reversibly deintercalated-embedded in the positive electrode during charge and discharge; and the second metal ion is reduced in the negative electrode during charging Deposited as a second metal, the second metal is oxidatively dissolved into a second metal ion during discharge; the second metal ion is selected from the group consisting of manganese ions, iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin An ion or a lead ion; the anion of the electrolyte includes one or more of a sulfate ion, a chloride ion, an acetate i
  • the present invention also provides a method for preparing graphene as described above, wherein the graphene is prepared by a chemical vapor deposition method, and the preparation method comprises the following steps:
  • Step 1 growing a graphene to form a graphene/catalyst composite structure by chemical vapor deposition on a catalyst having a porous structure;
  • the catalyst is selected from the group consisting of magnesium oxide, zinc oxide, copper oxide or aluminum oxide;
  • Step 2 removing the catalyst in the composite structure by etching to obtain the graphene.
  • the chemical vapor deposition reactor is heated under an inert gas atmosphere, and after reaching a preset temperature, the catalyst is placed in the chemical vapor deposition reactor, and the chemical vapor deposition is performed.
  • a carbon source gas is introduced into the reactor.
  • the preset temperature ranges from 820 to 875 °C.
  • the carbon source gas has a flow rate of 500-1000 ml/min, and the pass-in time is 5-30 minutes.
  • the carbon source gas is acetylene, ethylene or methane.
  • the graphene/catalyst composite structure is placed in hydrochloric acid for etching to remove the catalyst.
  • the graphene provided by the invention has a uniform continuous porous network structure and hydrophilicity, and has excellent long-range conductivity and ion-conducting ability. It is used as a conductive agent in an aqueous secondary battery, and the battery has significantly improved rate performance and cycle performance.
  • the method for preparing graphene provided by the invention is simple, and the fluidized bed used for preparing graphene is easy to be pilot-scaled, and the preparation method has commercial application prospects.
  • Figure 1-3 is a graph of charge and discharge cycle performance of batteries B1, B3 and B4;
  • Figure 4 is a charge and discharge curve of the battery B5 at a rate of 0.2 C;
  • Figure 6 is a graph showing the charge and discharge cycle performance of the battery B5 at a 3C rate
  • Fig. 7 is a graph showing the charge and discharge cycle performance of the battery S1 at a 3C rate.
  • Figure 8 is a scanning electron microscope and transmission electron micrograph of the materials PG, RGO and EG;
  • Figure 9 is a scanning electron micrograph of the positive electrodes C1, C2 and C3;
  • Figure 10 is a graph showing the rate performance of the batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO, and LiMn 2 O 4 /EG;
  • Figure 11 is a cycle performance diagram of the batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO, and LiMn 2 O 4 /EG;
  • Fig. 12 is an electrochemical impedance spectrum of the battery LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG after 300 cycles.
  • the present invention provides an electrolyte comprising an electrolyte and a solvent; wherein the electrolyte comprises: a negative electrode metal ion capable of being reducedly deposited as a metal in the negative electrode during charging and discharging and capable of reversible oxidative dissolution of the metal; and a positive electrode ion participating in the positive electrode reaction; And an additive ion selected from at least one of Na, Mg, Al, NH 4 + , Ni, Co, Ce, Fe, Pb or Mn ions, and the additive ion is different from the above negative electrode metal ion and Positive ion.
  • the additive ions of the present invention have a concentration in the electrolyte of from 0.001 M to 8 M (mol/L).
  • the concentration of the Al ion as the additive ion in the electrolytic solution is 0.001 M to 8 M (mol/L), preferably 0.01 M to 5 M, and more preferably 0.1 M to 2 M.
  • the concentration of the Na, Mg, and/or Ni as the additive ion in the electrolytic solution is 0.001 M or more and less than 1 M, preferably 0.5 M or less, more preferably 0.3 M or less, further preferably 0.2 M or less, and more preferably 0.1 M or less. More preferably, it is 0.09 M or less, more preferably 0.08 M or less, more preferably 0.07 M or less, still more preferably 0.06 M or less, further preferably 0.05 M or less, and preferably 0.001 M or more, preferably 0.005 M or more, and preferably 0.01 M or more.
  • the concentration of the Ce, Fe, Mn, Pb, and/or Co as an additive ion in the electrolytic solution is more than 0.1 M and 8 M or less, preferably 0.2 M or more, more preferably 0.3 M or more, and still more preferably 0.4 M or more. It is more preferably 0.5 M or more, still more preferably 0.8 M or more, and is preferably 8 M or less, more preferably 5 M or less, and still more preferably 2 M or less.
  • the concentration of the NH 4 + ion as an additive ion in the electrolytic solution is 0.25 M or more and 8 M or less, preferably 0.25 to 4 M, and more preferably 0.5 to 2 M.
  • the additive ions are Na, Mg, K or Ni
  • the positive electrode ions and the negative electrode metal ions at this time are different from the additive ions, that is, they are not selected from Na, Mg, K and/or Ni.
  • the positive electrode ions and the negative electrode metal ions at this time are different from the additive ions, that is, they are not selected from Ce, Fe, Mn, Pb and/or Co.
  • the concentration of the additive ion in the electrolytic solution in the present invention means the concentration in the electrolytic solution when the ion is used as the additive ion. Further, if two or more of the above additive ions are used, the above concentrations refer to the respective concentrations of each of the additive ions.
  • the additive ion is derived from an inorganic additive added to the electrolyte, and the inorganic additive is selected from the group consisting of a sodium compound, a magnesium compound, an aluminum compound, an ammonium compound, a nickel compound, a cobalt compound, a cerium compound, an iron compound, a lead compound, and a manganese compound. Or two or more.
  • the purpose of using a solvent in the present invention is to dissolve an electrolyte component including a negative electrode metal ion, a positive electrode ion, and an additive ion, and ionize the electrolyte in a solvent to finally generate freely movable cations and anions in the electrolyte. .
  • the solvent of the present invention is preferably water and/or an alcohol.
  • alcohols include, but are not limited to, methanol or ethanol.
  • the negative electrode metal ion in the electrolyte can be reduced and deposited as a metal in the negative electrode during charge and discharge, and the metal can be reversibly oxidized into a metal ion during discharge. That is, when the battery is charged, the negative electrode metal ions in the electrolyte are reduced to metal and deposited on the negative electrode; when the battery is discharged, the metal is oxidized into metal ions and eluted from the negative electrode to enter the electrolyte.
  • the negative metal ion is a zinc ion.
  • the concentration of the negative electrode metal ion in the electrolyte ranges from 0.5 to 15 M.
  • the negative electrode metal ion is present in the electrolyte in the form of a chlorate, a sulfate, a nitrate, an acetate, a formate or a phosphate.
  • the negative electrode metal ion is present in the electrolyte in the form of a sulfate, acetate or a mixture of sulfate and acetate.
  • the electrolyte also includes positive electrode ions that participate in the positive electrode reaction.
  • the positive electrode ion may be a metal ion that is inserted and removed at the positive electrode of the battery or an ion that participates in the positive electrode redox reaction during charge and discharge.
  • the positive electrode ion is a metal ion which is inserted and removed at the positive electrode of the battery.
  • the positive electrode ions in the electrolyte are embedded in the positive electrode material; when the battery is discharged, the ions embedded during charging are again released from the positive electrode material into the electrolyte.
  • the positive electrode ion is a lithium ion.
  • the concentration of the positive electrode ions in the electrolytic solution ranges from 0.1 to 30 M.
  • the positive electrode ion is present in the electrolyte in the form of a chlorate, a sulfate, a nitrate, an acetate, a formate or a phosphate.
  • the positive electrode ion is present in the electrolyte in the form of a sulfate, acetate or a mixture of a sulfate and an acetate.
  • the positive electrode ion is an ion that participates in a positive electrode redox reaction during charge and discharge.
  • the ions in the electrolyte are oxidized; when the battery is discharged, the oxidized active material is reduced during charging.
  • the positive electrode ion is selected from one or both of a bromide ion and a vanadium ion.
  • the concentration thereof may be, for example, 0.5 M to 20 M.
  • zinc ions and lithium ions are included in the electrolyte. As the charge and discharge progresses, zinc ions are deposited-dissolved at the negative electrode, and lithium ions are intercalated-extracted at the positive electrode.
  • the electrolyte includes bromide ions and zinc ions.
  • the electrolyte includes bromide ions and zinc ions.
  • zinc ions are deposited-dissolved at the negative electrode, and the bromide ions undergo an oxidation-reduction reaction at the positive electrode.
  • the present invention by adding a specific additive ion in the above concentration range, dendrite and corrosion existing when the negative electrode metal ion (for example, zinc ion) is charged and discharged in an aqueous solution can be remarkably suppressed.
  • the cycle performance and charge and discharge capacity of the battery are remarkably improved, and it has been unexpectedly found that deep discharge of the battery can also be achieved.
  • the open circuit voltage and capacity retention rate of the battery can be remarkably improved, and the discharge capacity loss is reduced to about 70% of the battery to which no given additive ion is added.
  • the capacity retention rate after 50 cycles, 100 cycles and 150 cycles can be maintained at a high level, especially after 150 cycles, the capacity retention rate is significantly higher than without the use of additives, so that the cycle is maintained. The rate can always be maintained above about 95%.
  • the battery prepared by using the electrolyte of the invention has good suppression of adverse reactions such as corrosion, hydrogen evolution and dendrite of the negative electrode, thereby solving the problems difficult to be solved in the field and improving the cycle performance and charge and discharge capacity of the battery. .
  • the electrolytic solution of the present invention when used, it has been unexpectedly found that deep discharge of the battery can be realized.
  • the battery according to the present invention (described below) is used, it is generally only possible to discharge to, for example, about 1.4 V, and by using this.
  • the above electrolyte solution of the invention can achieve deep discharge and discharge to about 0.5V. It is presumed that this is also a remarkable effect by suppressing problems such as corrosion of the negative electrode, hydrogen evolution, and dendrites.
  • the additive ion in the electrolyte of the present invention is one or both of magnesium ion or manganese ion.
  • the inorganic additive providing magnesium or manganese ions is selected from one or more of their respective oxides, acetates, carbonates, sulfates, nitrates.
  • the magnesium compound is magnesium sulfate and the manganese compound is manganese sulfate.
  • the electrolyte using magnesium ion or manganese ion can further improve the cycle performance and charge and discharge capacity of the battery, and can realize deep discharge of the battery.
  • the method of adding the inorganic additive to the electrolyte may be selected according to different conditions of the electrolyte or the separator.
  • the means of addition include, but is not limited to, direct addition to the electrolyte, or addition of the suspension droplets to the membrane. More preferably, the inorganic additive is directly added to the electrolyte and then charged Decompose the droplet onto the diaphragm.
  • the pH of the electrolyte of the present invention is preferably in the range of 3 to 7.
  • the pH range can be adjusted by a buffer. If the pH of the electrolyte is too high, it may affect the concentration of zinc ions in the electrolyte. If the pH of the electrolyte is too low, the corrosion of the electrode material may be aggravated. Keeping the pH range of the electrolyte at 3 to 7 can effectively ensure the concentration of various ions in the electrolyte and avoid electrolytic corrosion.
  • the present invention also relates to a battery comprising a positive electrode, a negative electrode, and the above electrolyte.
  • the positive electrode of Embodiment 1 of the present invention may include a positive electrode current collector and a positive electrode material, and the positive electrode material includes a positive electrode active material.
  • the positive electrode current collector is not particularly limited, and those skilled in the art can appropriately select them as needed.
  • the positive current collector usually acts as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction, that is, within the operating voltage range of the battery, the positive current collector can be stably present in the electrolyte without substantially causing side reactions, thereby ensuring stable battery. Cycle performance.
  • the size of the cathode current collector can be determined according to the use of the battery. For example, if used in a large battery requiring high energy density, a large positive current collector can be used.
  • the thickness of the positive electrode current collector is not particularly limited and is usually about 1 to 100 ⁇ m.
  • the shape of the positive electrode current collector is not particularly limited, and may be, for example, a rectangle or a circle.
  • the material constituting the cathode current collector is not particularly limited, and for example, a metal, an alloy, a carbon-based material, or the like can be used.
  • the carbon-based material may be one selected from the group consisting of glassy carbon, graphite, carbon felt, carbon fiber, or a conductive material having a 3D double continuous structure.
  • the conductive material having a 3D double continuous structure includes, but is not limited to, foamed carbon.
  • Graphite includes, but is not limited to, graphite foil and graphite sheets.
  • the metal may be one selected from the group consisting of Al, Fe, Cu, Pb, Ti, Cr, Mo, Co, Ag or the above-mentioned metal which has been passivated.
  • the alloy may be one selected from the group consisting of stainless steel, aluminum alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti-Pt alloy, Pt-Rh alloy, or passivated alloy.
  • the stainless steel includes a stainless steel foil or a stainless steel mesh. Specifically, the stainless steel may be, but not limited to, a 300 series stainless steel such as stainless steel 304, 316, 316L or 316P.
  • the model of the aluminum alloy may be, but not limited to, an aluminum alloy of the 6000 series, such as an aluminum alloy 6061.
  • the positive electrode active material layer is formed on the positive electrode current collector.
  • the positive electrode active material layer may be formed on one surface of the positive electrode current collector or may be formed on both surfaces of the positive electrode current collector.
  • the positive electrode active material is not particularly limited as long as it can reversibly elute-embed metal ions, and those skilled in the art can appropriately select them as needed.
  • the positive electrode active material may be selected from the group consisting of the general formula Li 1+x Mn y M z O k (wherein -1 ⁇ x ⁇ 0.5, 1 ⁇ y ⁇ 2.5 , 0 ⁇ z ⁇ 0.5, 3 ⁇ k ⁇ 6, M is a spinel represented by at least one selected from the group consisting of Na, Li, Co, Mg, Ti, Cr, V, Zn, Zr, Si, and Al) a compound of the structure, having the general formula Li 1+x M y M′ z M′′ c O 2+n (wherein ⁇ 1 ⁇ x ⁇ 0.5, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ c ⁇ 1 , -0.2 ⁇ n ⁇ 0.2, M, M', M" are respectively selected from at least one of Ni, Mn, Co, Mg, Ti, Cr, V, Zn, Zr, Si or Al) a compound of the structure, and a formula of Li
  • the positive electrode active material may, for example, be a sodium iron composite oxide (NaFeO 2 ) or a sodium cobalt composite oxide (NaCoO 2 ) as a layered oxide material.
  • examples thereof include a sodium manganese composite oxide (NaMn 2 O 4 ), a sodium nickel manganese composite oxide (NaNi 1/2 Mn 3/2 O 2 ), and the like.
  • a sodium iron phosphate compound (NaFePO 4 ), a sodium manganese phosphate compound (NaMnPO 4 ), a sodium cobalt phosphate compound (NaCoPO 4 ), or the like, which is an olivine-based material may be mentioned.
  • Na 2 FePO 4 F, Na 2 MnPO 4 F, Na 2 CoPO 4 F, or the like, which is a fluorinated olivine-based material may be mentioned.
  • LiMn 2 O 4 can not represent the general formula of "manganese manganate" which is widely used, but should be of the general formula Li 1+x
  • the Mn y M z O k is broadly included, and variously modified LiMn 2 O 4 positive electrode active materials are widely included.
  • LiFePO 4 and LiCoO 2 should also be broadly understood to include modifications through various doping, cladding, etc., which are in accordance with Li x M 1-y M' y (XO 4 )n and Li 1+, respectively. a positive electrode active material of x M y M' z M" c O 2+n .
  • the positive electrode active material of the first embodiment is a substance capable of reversibly extracting-intercalating lithium ions
  • the positive electrode active material is a substance capable of reversibly eluting-embeding sodium ions
  • NaVPO4F or the like is preferably used.
  • the positive electrode further includes a positive electrode current collector supporting the positive electrode active material, and the material of the positive electrode current collector is selected from one of a carbon-based material, a metal or an alloy.
  • the positive electrode material in addition to the positive electrode active material, further includes a positive electrode conductive agent and a positive electrode binder to enhance the performance of the positive electrode, depending on the actual situation.
  • the positive electrode conductive agent is selected from one or more of a conductive polymer, activated carbon, graphene, carbon black, graphite, carbon fiber, metal fiber, metal powder, and metal flake.
  • the positive electrode conductive agent is graphene
  • the graphene is composed of a single layer or a plurality of graphene structural units
  • the graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm.
  • the graphene has an average pore diameter ranging from 3-5 nm. In a preferred embodiment, the graphene has an average pore diameter ranging from 4 nm.
  • the size of graphene ranges from 200 to 1000 nm.
  • the size of the graphene oxide refers to the average length and width of the graphene oxide sheet layer, and the actual size may be deviated due to the flexibility of the graphene oxide sheet layer.
  • the graphene has a specific surface area of 300 to 2000 m 2 /g.
  • the positive electrode conductive agent graphene provided by the present invention is a graphene material having a uniform continuous porous network structure and a large specific surface area, that is, a porous graphene material having excellent long-range conductivity and ion-conducting ability. Meanwhile, compared with the hydrophobicity of the exfoliated graphene, the graphene in the present invention has a good hydrophilic property, and the porous structure is combined with hydrophilicity, so that graphene can be used as a conductive agent in a water-based secondary battery.
  • the water-based electrolyte is contained so that the aqueous electrolyte and the active material can be sufficiently contacted, and the graphene has a good application prospect as a conductive material in an aqueous battery.
  • the positive electrode binder may be selected from the group consisting of polyethylene oxide, polypropylene oxide, polyacrylonitrile, polyimide, polyester, polyether, fluorinated polymer, polydivinyl polyethylene glycol, polyethylene glycol. One of diacrylate, polyethylene glycol dimethacrylate, or a mixture and derivative of the above polymers. More preferably, the positive electrode binder is selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or styrene butadiene rubber (SBR).
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • SBR styrene butadiene rubber
  • the present invention provides a graphene composed of a single layer or a plurality of graphene structural units, and the graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm. Specifically, the graphene has an average pore diameter ranging from 3-5 nm. In a preferred embodiment, the graphene has an average pore diameter ranging from 4 nm.
  • the size of graphene ranges from 200 to 1000 nm.
  • the size of the graphene oxide refers to the average length and width of the graphene oxide sheet layer, and the actual size may be deviated due to the flexibility of the graphene oxide sheet layer.
  • the graphene has a specific surface area of 300 to 2000 m 2 /g.
  • the graphene provided by the present invention is a graphene material having a uniform continuous porous network structure and a large specific surface area, that is, a porous graphene material having excellent long-range conductivity and ion-conducting ability.
  • the graphene in the invention has good hydrophilic properties, and the porous structure combines hydrophilicity, so that graphene is used as a conductive agent in the water system secondary electricity.
  • the water-based electrolyte can be well accommodated, so that the aqueous electrolyte and the active material can be sufficiently contacted.
  • This graphene has a good application prospect as a conductive material in water-based batteries.
  • the positive electrode is a carbon electrode or a composite oxide electrode carbon electrode, and may be a graphite electrode.
  • the positive electrode may also be composed of a substrate and a paste containing a positive electrode active material attached thereto.
  • the positive electrode active material at this time may be, for example, zinc bromide, and the matrix is a porous conductive carbon material of carbon felt, graphite felt, carbon paper or carbon cloth.
  • the substance in which the negative electrode of the battery electrochemically reacts is a negative electrode reaction metal, and the negative electrode reaction metal can be oxidized and dissolved into a negative electrode metal ion and the negative electrode metal ion can be reversibly reduced and deposited as a negative electrode reaction metal.
  • the anode includes the anode current collector, and the anode current collector serves only as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction.
  • the anode current collector is a carrier for charging and discharging the anode.
  • the material of the anode current collector is selected from at least one of metal Ni, Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal, or elemental silicon, or carbon-based material, wherein carbon-based material Materials include graphite materials such as commercial graphite pressed foils in which the weight ratio of graphite ranges from 90 to 100%.
  • the material of the anode current collector may also be selected from stainless steel or passivated stainless steel.
  • Stainless steel includes, but is not limited to, stainless steel mesh and stainless steel foil.
  • stainless steel models can be 300 series stainless steel, such as stainless steel 304 or stainless steel 316 or stainless steel 316L.
  • the negative electrode includes a negative electrode active material supported on the negative electrode current collector in addition to the negative electrode current collector.
  • the negative electrode active material is a carrier for charging and discharging the negative electrode.
  • the negative electrode active material is zinc.
  • a zinc sheet is directly used as a negative electrode, and the zinc sheet serves as both a negative electrode current collector and a negative electrode active material. At this time, the zinc sheet is a carrier for charging and discharging the negative electrode.
  • the battery may be free of a separator.
  • a separator between the positive electrode and the negative electrode in the electrolyte.
  • the diaphragm can avoid short circuits caused by the connection of positive and negative electrodes caused by other unexpected factors.
  • the separator of the present invention is not particularly required as long as it is a separator which allows the electrolyte to pass through and is electrically insulated.
  • Various separators used in organic lithium ion batteries can be applied to the present invention.
  • the separator may also be other materials such as microporous ceramic separators.
  • the present invention provides a graphene composed of a single layer or a plurality of graphene structural units, and the graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm.
  • the graphene has an average pore diameter ranging from 3-5 nm. In a preferred embodiment, the graphene has an average pore diameter ranging from 4 nm.
  • the size of graphene ranges from 200 to 1000 nm.
  • the size of the graphene oxide refers to the average length and width of the graphene oxide sheet layer, and the actual size may be deviated due to the flexibility of the graphene oxide sheet layer.
  • the graphene has a specific surface area of 300 to 2000 m 2 /g.
  • the graphene provided by the present invention is a graphene material having a uniform continuous porous network structure and a large specific surface area, that is, a porous graphene material having excellent long-range conductivity and ion-conducting ability. Meanwhile, compared with the hydrophobicity of the exfoliated graphene, the graphene in the present invention has a good hydrophilic property, and the porous structure is combined with hydrophilicity, so that graphene can be used as a conductive agent in a water-based secondary battery.
  • the water-based electrolyte is contained so that the aqueous electrolyte and the active material can be sufficiently contacted, and the graphene has a good application prospect as a conductive material in an aqueous battery.
  • the invention also provides a method for preparing graphene, which is prepared by one-step chemical vapor deposition (CVD).
  • the preparation method comprises the following steps: Step 1: The carbon source gas is grown on the catalyst by chemical vapor deposition to form a graphene/catalyst composite structure; Step 2: removing the catalyst in the composite structure by etching to obtain the graphene.
  • the chemical vapor deposition reactor is heated under an inert gas atmosphere, and after reaching a preset temperature, the catalyst is placed in a chemical vapor deposition reactor, and a carbon source gas is introduced into the reactor.
  • This arrangement can save process time and inert gas better and reduce the production cost.
  • the catalyst has a porous structure selected from the group consisting of magnesium oxide, zinc oxide, copper oxide or aluminum oxide.
  • the obtained graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm, and graphene has an average pore diameter ranging from 3-5 nm.
  • Porous catalysts and porous graphene have similar pore distributions because the growth of porous graphene is carried out using a porous catalyst as a template.
  • the obtained graphene has a size ranging from 200 to 1000 nm and a specific surface area of from 300 to 2000 m 2 /g.
  • the preset temperature range is 820-875 °C.
  • the prepared graphene has a more uniform and continuous network porous structure, and the pore size is equivalent, and the material has good uniformity.
  • the carbon source gas is acetylene, ethylene or methane.
  • the carbon source gas flow rate is 500-1000 ml/min, and the access time is 5-30 minutes.
  • a suitable carbon source gas flow rate contributes to uniform pyrolysis of the carbon source gas and growth on the magnesium oxide, so that the finally prepared graphene has a uniform porous structure.
  • step two the graphene/catalyst composite structure is placed in hydrochloric acid for etching to remove the catalyst.
  • a quartz tube furnace which is vertically disposed is used as a chemical vapor deposition reactor using magnesium oxide as a catalyst, and a quartz tube furnace is heated in an argon atmosphere.
  • the temperature reached the preset temperature of 875 ° C the magnesia catalyst was put into the reactor, the carbon source gas methane was introduced, and the gas flow rate of methane was 800 ml/min, and it was passed for 10 minutes. Subsequently, the mixture was cooled to room temperature, the obtained material was taken out, magnesium oxide was removed by washing with hydrochloric acid, and the product was filtered and dried at 80 ° C overnight to obtain porous graphene.
  • the present invention provides a simple process for preparing graphene by chemical vapor deposition, and the prepared graphene has a porous structure, good hydrophilicity and excellent conductivity and conductivity. .
  • the chemical vapor deposition fluidized bed used for the simultaneous production of graphene is easy to amplify, and the preparation method provided by the invention has good commercial application prospects.
  • the invention also provides a conductive agent comprising the graphene described above, the graphene is a porous structure, and has excellent conductivity and ion guiding ability.
  • the present invention also provides a positive electrode comprising a positive electrode material, the positive electrode material comprising a positive electrode active material and a positive electrode conductive agent, and the positive electrode conductive agent comprising graphene as described above.
  • the present invention also provides a battery comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, the positive electrode including a positive electrode material, the positive electrode material including a positive electrode active material and a positive electrode conductive agent, and the positive electrode conductive agent including the graphite as described above Alkene.
  • the positive active material participates in the positive electrode reaction and is capable of reversibly extracting-embedding the first metal ion.
  • the first metal ion is selected from the group consisting of lithium ions, sodium ions or magnesium ions.
  • the positive electrode active material may be a compound capable of reversible elution-intercalation lithium ion-doped spinel structure conforming to the general formula Li 1+x Mn y M z O k , wherein -1 ⁇ x ⁇ 0.5, 1 ⁇ y ⁇ 2.5,0 ⁇ z ⁇ 0.5, 3 ⁇ k ⁇ 6, M is at least one selected from the group consisting of Na, Li, Co, Mg, Ti, Cr, V, Zn, Zr, Si, and Al.
  • the positive electrode active material contains LiMn 2 O 4 . More preferably, the positive electrode active material contains doped or coated modified LiMn 2 O 4 .
  • the positive electrode active material may be a compound capable of reversibly deintercalating-intercalating lithium ion in a layered structure conforming to the general formula Li 1+x M y M′ z M′′ c O 2+n , wherein ⁇ 1 ⁇ x ⁇ 0.5, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ c ⁇ 1, -0.2 ⁇ n ⁇ 0.2, M, M', M" are respectively selected from Ni, Mn, Co, Mg, Ti, Cr, V, Zn, Zr At least one of Si, Si or Al.
  • the positive electrode active material may also be a compound having a olivine structure capable of reversibly extracting-intercalating lithium ions according to the general formula Li x M 1-y M' y (XO 4 ) n , wherein 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 0.6, 1 ⁇ n ⁇ 1.5, M is selected from Fe, Mn, V or Co, and M' is at least one selected from the group consisting of Mg, Ti, Cr, V or Al, and X is at least one selected from the group consisting of S, P or Si.
  • M is selected from Fe, Mn, V or Co
  • M' is at least one selected from the group consisting of Mg, Ti, Cr, V or Al
  • X is at least one selected from the group consisting of S, P or Si.
  • the positive electrode active material is one or more selected from the group consisting of LiMn 2 O 4 , LiFePO 4 or LiCoO 2 .
  • LiMn 2 O 4 can not represent the general formula of "manganese manganate" which is widely used, but should be of the general formula Li 1+x
  • the Mn y M z O k is broadly included, and variously modified LiMn 2 O 4 positive electrode active materials are widely included.
  • LiFePO 4 and LiCoO 2 should also be broadly understood to include modifications through various doping, cladding, etc., which are in accordance with Li x M 1-y M' y (XO 4 ) n and Li 1+, respectively. a positive electrode active material of x M y M' z M" c O 2+n .
  • the positive electrode active material is a lithium ion elution-embedded compound
  • a compound such as LiMn 2 O 4 , LiFePO 4 , LiCoO 2 , LiM x PO 4 , LiM x SiO y (wherein M is a variable valence metal) may be selected.
  • the NaDCO 4 F a compound capable of eluting-inserting sodium ions
  • MgM x O y where M is a metal, 0.5 ⁇ x ⁇ 3, 2 ⁇ y ⁇ 6
  • M is a metal, 0.5 ⁇ x ⁇ 3, 2 ⁇ y ⁇ 6
  • a compound capable of deintercalating-embeding an ion or a functional group can be used as a positive electrode active material of the battery of the present invention, and therefore, the present invention is not limited to a lithium ion battery.
  • the positive electrode conductive agent accounts for 2% to 15% by mass of the positive electrode material, and the positive electrode active material has a mass percentage of 80% to 90% of the positive electrode material, thereby ensuring excellent conductivity of the positive electrode material. At the same time of electron and ion conductivity, the positive electrode has a higher capacity. More preferably, the positive electrode conductive agent accounts for 3% to 10% by mass of the positive electrode material.
  • a positive electrode binder may be added to the positive electrode material to improve the performance of the positive electrode.
  • the positive electrode binder is selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or styrene butadiene rubber (SBR).
  • the positive active material is supported on the positive current collector, and the positive current collector acts as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction, that is, in the operating voltage range of the battery, the positive current collector can stably exist in the electrolyte without substantially occurring. Side reaction to ensure stable cycle performance of the battery.
  • the material of the cathode current collector is selected from one of a carbon-based material, a metal or an alloy.
  • the carbon-based material is selected from the group consisting of glassy carbon, graphite foil, graphite flakes, foamed carbon, carbon felt, carbon cloth, and carbon fiber.
  • the cathode current collector is graphite, such as a commercial graphite pressed foil, wherein the weight ratio of graphite ranges from 90 to 100%.
  • the metal includes one of Ni, Al, Fe, Cu, Pb, Ti, Cr, Mo, Co, Ag or the above-mentioned metal which has been passivated.
  • the alloy includes one of stainless steel, carbon steel, Al alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti-Pt alloy, Pt-Rh alloy or passivation treatment of the above metal.
  • Stainless steel includes stainless steel mesh, stainless steel foil, stainless steel models include but are not limited to stainless steel One of 304 or stainless steel 316 or stainless steel 316L.
  • the passivation treatment is performed on the positive current collector, and the main purpose is to form a passivated oxide film on the surface of the positive current collector, thereby stably collecting and conducting electrons during charging and discharging of the battery. , and will not participate in the battery reaction to ensure stable battery performance.
  • the positive current collector passivation treatment method includes a chemical passivation treatment or an electrochemical passivation treatment.
  • the chemical passivation treatment includes oxidizing the cathode current collector by an oxidizing agent to form a passivation film on the surface of the cathode current collector.
  • the principle of oxidant selection is that the oxidant can form a passivation film on the surface of the positive current collector without dissolving the positive current collector.
  • the oxidizing agent is selected from, but not limited to, concentrated nitric acid or sorghum sulfate (Ce(SO 4 ) 2 ).
  • the electrochemical passivation treatment comprises electrochemically oxidizing the cathode current collector or charging and discharging the battery containing the cathode current collector to form a passivation film on the surface of the cathode current collector.
  • the positive current collector is further coated with a conductive film, wherein the selection of the positive current collector can be referred to the selection one, and details are not described herein again.
  • the selection of the conductive film satisfies the requirement that it can be stably present in the aqueous electrolyte, is insoluble in the electrolyte, does not swell, the high voltage cannot be oxidized, and is easily processed into a dense, watertight, and electrically conductive material.
  • the conductive film can protect the positive current collector from corrosion of the positive current collector by the aqueous electrolyte.
  • it is advantageous to reduce the contact internal resistance between the positive electrode sheet and the positive electrode current collector, and to increase the energy of the battery.
  • the conductive film has a thickness of 10 ⁇ m to 2 mm, and the conductive film can not only effectively protect the positive electrode current collector, but also reduce the contact internal resistance between the positive electrode active material and the positive electrode current collector, thereby improving the energy of the battery.
  • the cathode current collector has opposite first and second faces.
  • the first surface and the second surface of the cathode current collector are coated with a conductive film.
  • the conductive film contains a polymer as an essential component, and the polymer accounts for 50 to 95% by weight of the conductive film.
  • the polymer is selected from a thermoplastic polymer.
  • the conductive film there are two possible forms: (1) the polymer is a conductive polymer; (2) in addition to the polymer, the conductive film further contains a conductive filler.
  • Conductive polymer materials are required to be electrically conductive but electrochemically inert, i.e., not ionically conductive as a charge transfer medium.
  • conductive polymers include, but are not limited to, polyacetylene, polypyrrole, polythiophene, polyphenylene sulfide, polyaniline, polyacrylonitrile, polyquinoline, polyparaphenylene, and any mixtures thereof.
  • the conductive polymer itself is electrically conductive, but the conductive polymer can also be doped or modified to further increase its electrical conductivity. From conductive properties and stable use in batteries
  • the conductive polymer is preferably polyaniline, polypyrrole, polythiophene or polyacetylene.
  • conductive fillers require small surface area, difficulty in oxidation, high crystallinity, electrical conductivity, but electrochemical inertness, ie, ion conduction that does not act as a charge transfer medium.
  • Materials for the conductive filler include, but are not limited to, conductive polymers, carbon-based materials, or metal oxides.
  • the mass percentage of the conductive filler in the conductive film ranges from 5 to 50%.
  • the average particle diameter of the conductive filler is not particularly limited, and is usually in the range of 100 nm to 100 ⁇ m.
  • the polymer in the conductive film preferably contains a non-conductive polymer that functions to bond the conductive filler, and the non-conductive polymer enhances the bonding of the conductive filler, improving the reliability of the battery.
  • the non-conductive polymer is a thermoplastic polymer.
  • thermoplastic polymers include, but are not limited to, polyolefins such as polyethylene, polypropylene, polybutene, polyvinyl chloride, polystyrene, polyamide, polycarbonate, polymethyl methacrylate, polyoxymethylene, polyphenylene.
  • polyolefins such as polyethylene, polypropylene, polybutene, polyvinyl chloride, polystyrene, polyamide, polycarbonate, polymethyl methacrylate, polyoxymethylene, polyphenylene.
  • ether, polysulfone, polyethersulfone, styrene butadiene rubber or polyvinylidene fluoride are preferred.
  • polyolefins polyamides and polyvinylidene fluoride.
  • the conductive film can be bonded to the positive current collector by hot press lamination, vacuuming or spraying.
  • the cathode current collector comprises a carrier and graphite coated on the carrier.
  • the thickness of the positive electrode current collector needs to be appropriately selected.
  • the thickness of the graphite ranges from 0.1 to 0.2 mm; the thickness of the carrier is less than 1 mm, and preferably, the thickness of the carrier ranges from 0.1 to 0.2 mm.
  • the carbon content of the graphite is greater than 97% to avoid the influence of impurities in the graphite on the performance of the battery.
  • the form of graphite is graphite foil, also known as graphite foil.
  • graphite paper is processed from a series of graphite powders into a flexible, lightweight paper-like graphite.
  • the density of the graphite paper is greater than 1.0 g/cm 3 , and the density of the graphite paper is larger, and the structure is denser, thereby ensuring that the surface of the graphite paper used in the water-based battery is not easily foamed and the performance is stable.
  • the support itself is electrochemically inert and, as is well known to those skilled in the art, is electrochemically inert, i.e., the support does not participate in any electrochemical reaction.
  • the carrier mainly functions to carry graphite, thereby improving the mechanical properties of the graphite, and the graphite mainly functions to collect and conduct electrons.
  • the material of the carrier is selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, One of polyethylene, polypropylene, polyamide, polyurethane, and polyacrylonitrile. These polymeric materials can be stably present in the positive current collector without participating in the electrochemical reaction, saving weight for the higher energy density output of the battery.
  • the carrier is a nylon mesh, ie a polyamide.
  • the graphite paper is coated on the carrier by hot pressing, rolling or gluing.
  • the negative electrode can be in three different forms depending on its structure and function:
  • the negative electrode includes only the negative electrode current collector, and the negative electrode current collector serves only as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction.
  • the anode current collector is a copper foil, a stainless steel mesh, a stainless steel foil or a graphite foil.
  • the negative electrode includes only the negative electrode active material, and the negative electrode active material simultaneously serves as the negative electrode current collector.
  • the second metal ion is zinc ion and the negative electrode is zinc foil.
  • the zinc foil can participate in the negative electrode reaction.
  • the negative electrode includes a negative electrode active material and a negative electrode current collector, and the negative electrode active material is supported on the negative electrode current collector.
  • the negative electrode active material is the same as the second metal.
  • the negative electrode active material is also metal Zn.
  • the negative electrode includes a brass foil and a zinc foil, the brass foil serves as a negative electrode current collector, and the zinc foil corresponds to the negative electrode active material and can participate in the negative electrode reaction.
  • the negative electrode active material exists in the form of a sheet or a powder.
  • the negative electrode active material forms a composite layer with the negative electrode current collector.
  • the anode active material is a powder
  • the second metal powder is slurried, and then the slurry is coated on the anode current collector to form a cathode.
  • the negative electrode conductive agent and the negative electrode binder are added as needed to improve the performance of the negative electrode.
  • the electrolyte includes an electrolyte and a solvent water; the electrolyte is capable of at least ionizing the first metal ion and the second metal ion; the first metal ion can be reversibly extracted-embedded in the positive electrode during charging and discharging; and the second metal ion is in the negative electrode during charging
  • the reduction deposition is a second metal, and the second metal is oxidized and dissolved into a second metal ion during discharge.
  • the second metal ion is selected from the group consisting of manganese ions, iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin ions or lead ions.
  • the first metal ion of the present invention is selected from the group consisting of lithium ions, while the second metal ion is selected from the group consisting of zinc ions, i.e., the cations in the electrolyte are lithium ions and zinc ions.
  • the anion in the electrolyte may be any anion which does not substantially affect the positive and negative electrode reactions and the dissolution of the electrolyte in the solvent.
  • it may be a sulfate ion, a chloride ion, an acetate ion, a formate ion, a phosphate ion, an alkylsulfonate ion, a mixture thereof, or the like.
  • the alkylsulfonate ion may be a methanesulfonate ion or the like.
  • the concentration of each ion in the electrolyte can be changed according to different conditions of different electrolytes, solvents, and application fields of the battery.
  • the concentration of the first metal ion is 0.1 to 10 mol/L.
  • the concentration of the second metal ion in the electrolytic solution is 0.5 to 15 mol/L.
  • the concentration of the anion in the electrolytic solution is from 0.5 to 12 mol/L.
  • the pH of the electrolyte is 2-8.
  • a separator is further provided between the positive electrode and the negative electrode in the electrolytic solution.
  • the diaphragm can avoid short circuits caused by the connection of positive and negative electrodes caused by other unexpected factors.
  • the separator is not particularly required as long as it is a separator that allows the electrolyte to pass through and is electrically insulated.
  • Various separators used in organic lithium ion batteries can be applied to the present invention.
  • the separator may also be a microporous ceramic separator, glass fiber AGM or AFG.
  • the battery of the invention adopts porous graphene as the positive electrode conductive agent of the battery, and the graphene has a uniform continuous porous network structure and good hydrophilic property, can well accommodate the aqueous electrolyte, and makes the aqueous electrolyte and the active material. It can be fully contacted to improve the electronic conductivity and ionic conductivity of the positive electrode material, thereby improving the cycle life and rate performance of the battery positive electrode.
  • Such graphene has a good application prospect in water-based batteries as a conductive material.
  • Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively, and MgSO 4 was further added to deionized water to a concentration of 0.05. M.
  • Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively, and MgSO 4 was further added to deionized water to a concentration of 0.25. M.
  • Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively, and MgSO 4 was further added to deionized water to a concentration of 0.5. M.
  • Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively.
  • the positive electrode active material lithium manganate LMO, binder hydroxymethyl cellulose CMC, styrene-butadiene rubber SBR, and conductive agent graphite KS15 were mixed in water at a mass ratio of 84.5:1.5:2:12 to form a uniform positive electrode slurry.
  • the positive electrode slurry was coated on a positive electrode current collector formed active material layer, which is then tableted to prepare a positive electrode sheet, the LMO active material areal density of 250g / m 2, an area of 1cm 2.
  • the electrolyte was prepared by using the above electrolytes 1-1, 1-2, and 1-4, the negative electrode was made of zinc foil, and the separator was made of glass fiber separator AGM to prepare a Swagelok battery.
  • the corresponding Swagelok batteries are denoted as B1, B2, and B4, respectively.
  • a Swagelok battery was prepared using the same positive electrode, negative electrode, separator, and comparative electrolyte 1, designated S1.
  • the open circuit voltage (OCV) increases with the additive ion Mg ion concentration. increase.
  • the open circuit voltage of B4 battery with 0.5M magnesium ion is 2.01V, which is about 50mV higher than the open circuit voltage of S1 battery, and the discharge capacity loss is only 3%, which is lower than the discharge capacity loss of 7% and the discharge capacity loss is lower.
  • the magnitude reached 57%.
  • the OCV of a B2 battery with 0.05M Mg ions added was increased to 1.98V, and the open circuit voltage was increased by about 20mV compared to the S1 battery.
  • the discharge capacity loss of B2 is about 5%, and the discharge capacity loss of S1 is 7%, and the discharge capacity loss of B2 is reduced to about 70% of S1.
  • the capacity retention rate of the battery is improved, indicating that the self-discharge rate of the battery and the loss of the positive conductive agent carbon are reduced.
  • the size of the lithium ion is relatively small, and it can freely move in the crystal structure of lithium manganate during charge and discharge.
  • the size of the additive ions such as Na ions, Mg ions, and Al ions is relatively large, and cannot be embedded in the crystal structure of lithium manganate. Therefore, the specific capacity of the battery does not increase due to the increase of these additive ions.
  • these additive ions are free to move in the electrolyte and hinder the movement of lithium ions.
  • the lithium ion elution-embedded battery self-discharge reaction rate is lowered.
  • the additive ions increase the oxygen evolution potential and slow down the occurrence of side reactions in which other ions in the battery may react with oxygen to produce oxides.
  • the batteries B1, B3, and B4 were subjected to a charge and discharge cycle test at a constant temperature of 3 C at a voltage ranging from 1.4 V to 2.1 V, and the test results are shown in Figs.
  • the battery having the Mg ion additive exhibits better cycle performance. As shown in Figures 1-3, at a high discharge rate, it takes about 50 cycles to achieve a stable discharge capacity. After the discharge capacity is stabilized, the fluctuation of the discharge capacity can be maintained within a cycle of several hundred weeks without exceeding 5%. In S1, the capacity retention rate after 300 cycles is only 80%. Therefore, by adding Mg ions, the cycle life and stability of the battery are significantly improved. The battery is expected to still have a 95% cycle retention after 1000 cycles. Internally disassembled the test battery, it can be seen that in the 800 cycle cycle, the battery with the Mg ion additive did not detect dendrite, while the battery without the Mg ion additive was found in the range of 100 to 300 cycles. Crystal phenomenon.
  • a battery Swagelok battery was prepared using the same positive electrode, negative electrode, and separator as the battery B1, and the electrolyte 2 was used as an electrolyte, and it was designated as B5.
  • the battery B5 was charged and discharged at a rate of 0.2 C at a normal temperature, wherein the charge cutoff voltage was 2.1 V, and the discharge cutoff voltage was 1.4, 1.2, 1.0, 0.5 up to 0 V.
  • the charge and discharge curves of the obtained battery were measured.
  • the discharge curve of Fig. 4 it can be seen from the discharge curve of Fig. 4 that if the discharge is 1.4 V, the discharge curve has two charge and discharge platforms, and the specific capacity of the battery is 110 mAh/g. If the discharge reaches about 0.5V, a new discharge platform appears at less than 1.4V. The specific capacity of the battery is about 180mAh/g. It can be seen that after the addition of Mn ions, the battery can achieve deep discharge.
  • the battery B5 was charged and discharged at a rate of 0.2 C at a normal temperature, and the battery cycle performance was measured. The result of discharging to 0.5 V is shown in Fig. 5. The battery was discharged to 0.5 V at a rate of 0.2 C, and the capacity of the battery was maintained at 160-180 mAh/g for more than 20 cycles.
  • the batteries S1 and B5 were charged and discharged at a normal temperature of 3 C, and the battery charge and discharge cycle performance was measured. The results are shown in Figs. 6 and 7, respectively.
  • Magnesium oxide (analytically pure, 20-30 nm) was mixed with deionized water and stirred with ultrasonic waves. The mixture was boiled in a reflux apparatus for 24 hours. After filtration and drying, the obtained material was ground to a fine powder. Finally, the obtained powder was calcined at 500 ° C for 30 minutes to remove water to obtain a layered structure having a porous structure. Magnesium oxide.
  • the magnesium oxide prepared above was used as a catalyst, and the quartz tube furnace which was vertically arranged was preheated to 875 ° C under an argon atmosphere, and then the magnesium oxide catalyst was put into the reactor, and methane gas was introduced thereto, and the gas flow rate was 800 ml/min. Pass for 10 minutes. Subsequently, the mixture was cooled to room temperature, the obtained material was taken out, magnesium oxide was removed by washing with hydrochloric acid, and the product was filtered and dried at 80 ° C overnight to obtain a porous graphene, which was designated as PG.
  • PG porous graphene
  • Comparative Example 3-1 Provided in Comparative Example 3-1 is redox graphene prepared by the modified hummers method. Specifically, 50 ml of a graphene oxide suspension having a concentration of 1 mg/ml was ultrasonically dispersed for 1 hour, 0.5 g of a reducing agent was added, and the resulting mixture was ultrasonicated at 60 ° C for 12 hours, and then the obtained material was freeze-dried. Redox graphene was obtained for 12 h and was designated as RGO.
  • Comparative Example 3-2 provides exfoliation graphene. Specifically, the high-speed fluid shear-assisted supercritical CO 2 stripping method is used to peel off the expanded graphite to obtain a peeled graphene, which is referred to as EG.
  • a, c and e are scanning electron microscope (SEM) photographs of the materials PG, RGO and EG, respectively; in Fig. 8, b, d and f are transmission electron microscope (TEM) photographs of the materials PG, RGO and EG, respectively.
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the porous graphene in Example 3-1 had a uniform porous network structure while the network structure was continuous.
  • the redox graphene in Comparative Example 3-1 was irregular in size and showed some aggregation.
  • the exfoliated graphene in Comparative Example 3-2 is a typical planar structure, and their thickness is still very thick, and it is difficult to separate them into a single layer or a few layers.
  • no porous and wrinkled structures were observed in redox graphene and exfoliated graphene.
  • porous graphene of Example 3-1 had a specific surface area of 1,500 m 2 /g and an average pore diameter of 4 nm. This data also corresponds to the TEM result of the porous graphene in Fig. 8.
  • Porous graphene PG, redox graphene RGO, and exfoliated graphene EG in Example 3-1, Comparative Example 3-1, and Comparative Example 3-2 were used as a positive electrode conductive agent.
  • Lithium manganate LiMn 2 O 4 (particle size about 0.2 ⁇ m, MTI Co., Ltd.), porous graphene PG, binder polyvinylidene fluoride (Kynar, HSV900) at a mass ratio of 83:10:7 at N-A
  • the pyrrolidone NMP Sigma-Aldrich, purity ⁇ 99.5%
  • the positive electrode slurry was coated on a positive current collector graphite foil (Alfa Aesar), vacuum dried at 60 ° C for 24 hours, and cut into a 12 mm diameter disk to prepare a positive electrode, which was designated as C1.
  • the positive electrode conductive agent was a redox graphene RGO, and the remaining composition of the positive electrode was prepared in the same manner as in Example 4-1 to obtain a positive electrode, which was designated as C2.
  • the positive electrode conductive agent was exfoliated graphene EG, and the remaining composition of the positive electrode was prepared in the same manner as in Example 4-1 to obtain a positive electrode, which was designated as C3.
  • Figure 9 is a SEM photograph of C1 (2a, b), C2 (2c), and C3 (2d). It is apparent from the figure that lithium manganate and porous graphene are uniformly mixed in C1, and the particles are in close contact with each other, and the porous graphene does not aggregate. In contrast, significant aggregation can be seen in C2 and C3 due to the difficulty in dispersing RGO and EG in the positive electrode material.
  • Example 4-1 The positive electrodes C1, C2, and C3 in Example 4-1, Comparative Example 4-1, and Comparative Example 4-2 were assembled into an aqueous battery, respectively.
  • the positive electrode of the battery is C1.
  • the negative electrode was a 12 mm diameter zinc sheet (Rotometals, thickness 0.2 mm).
  • the electrolytic solution used was an aqueous solution containing 1 mol/L zinc sulfate (Alfa Aesar, purity ⁇ 98%) and 2 mol/L lithium sulfate (Sigma Aldrich, purity ⁇ 98%). Adjust the electrolyte pH to 4.
  • the diaphragm was made of AGM diaphragm (NSG Corporation).
  • the positive electrode, the negative electrode, and the separator were assembled into a battery cell, placed in a casing, and then an electrolyte was injected, sealed, and assembled into a button cell, which was designated as LiMn 2 O 4 /PG.
  • the positive electrode of the battery was C2, and the rest of the battery was constructed and fabricated in the same manner as in Example 5-1, and the battery prepared was designated as LiMn 2 O 4 /RGO.
  • the positive electrode of the battery was C3, and the rest of the battery was constructed and fabricated in the same manner as in Example 5-1, and the prepared battery was designated as LiMn 2 O 4 /EG.
  • the batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG were subjected to a charge and discharge cycle test at a voltage range of 1.4-2.1 V at a rate of 4 C.
  • the test results are shown in FIG.
  • the battery LiMn 2 O 4 /PG has good cycle stability, and after 300 cycles of the battery, the discharge capacity is still 72 mAh/g, and the coulombic efficiency is close to 100%.
  • the battery LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG have poor cycle stability.
  • the electrochemical impedance spectrum of the battery LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO, and LiMn 2 O 4 /EG after charging and discharging cycles at 4 C rate for 300 times is shown in FIG. 12 . It can be seen from the figure that the battery LiMn 2 O 4 /PG has a small charge transfer resistance, which is in good agreement with its good rate performance.
  • Example 5-2 the mass ratio of LiMn 2 O 4 , porous graphene PG, and binder polyvinylidene fluoride was 89.7:3.3:7.
  • the positive electrode and the remaining composition of the battery were prepared in the same manner as in Example 5-1.
  • Example 5-3 the mass ratio of LiMn 2 O 4 , porous graphene PG, and binder polyvinylidene fluoride was 91:2:7.
  • the positive electrode and the remaining composition of the battery were prepared in the same manner as in Example 5-1.
  • the positive electrode conductive agent was graphite KS-6, and the remaining composition of the positive electrode was prepared in the same manner as in Example 5-1.
  • the positive electrode conductive agent was acetylene black, and the remaining composition and preparation method of the positive electrode were the same as those in Example 5-1.
  • the charge and discharge cycle test showed that the battery of Example 5-2 had the best rate performance, followed by the battery of Example 5-3.
  • the discharge capacity of the battery in Example 5-2 is higher than that of the battery in Example 5-3 by about 5-8 mAh/g, which is higher than that in the comparative examples 5-3 and 5-4.
  • the discharge capacity was about 10-20 mAh/g, and at 20C, the battery discharge capacity in Example 5-2 was higher than that in Example 5-3, and the discharge capacity was about 5 mAh/g, which was higher than the comparison ratios 5-3 and 5-.
  • the discharge capacity of the battery in 4 is about 20-40 mAh/g. More preferably, the battery rate performance in Example 5-2 is superior to the battery rate performance in Example 5-1.
  • the batteries in Examples 5-2, 5-3, Comparative Examples 5-3 and 5-4 were subjected to a charge and discharge cycle test at a voltage range of 1.4-2.1 V at a rate of 4 C.
  • the test results showed that the battery of Example 5-2
  • the discharge capacity was about 100 mAh/g after 300 cycles, the discharge capacity was about 90 mAh/g after 300 cycles of the battery in Example 5-3, and the discharge capacity was about 65 after 300 cycles of the battery in Comparative Examples 5-3 and 5-4. -75 mAh/g.
  • the battery of Example 5-2 showed excellent cycle performance. Also, the battery cycle performance in Example 5-2 was slightly better than that in Example 5-1.
  • any technical feature or combination of technical features described in the specification as a component of a certain technical solution may also be applied to the embodiments that can be implemented without obscuring the gist of the present invention.
  • Other technical solutions; and, while being able to implement and not clearly deviating from the gist of the present invention, the technical features described as the constituent parts of the different technical solutions may be combined in any manner to constitute other technical solutions.
  • the present invention also encompasses the technical solutions obtained by the combination in the above case, and these technical solutions are equivalent to those described in the present specification.

Abstract

An electrolyte solution. The electrolyte solution comprises electrolyte and a solvent. The electrolyte comprises: negative electrode ions which, on a negative electrode, can be reduced and deposited as metal which can be subjected to oxidative dissolution in a reverse manner in a charge and discharge process; positive electrode ions participating in a positive electrode reaction of a battery; and additive ions. Additive ions are selected from at least one of Na, Mg, Al, NH4+, Ni, Co, Ce, Fe, Pb or Mn, and are different from the negative electrode ions and the positive electrode ions. The present invention also relates to a battery comprising the electrolyte solution.

Description

电解液、电池和电池组Electrolyte, battery and battery pack 技术领域Technical field
本发明涉及一种用于电池的电解液，以及利用该电解液的电池。The present invention relates to an electrolyte for a battery, and a battery using the same.
背景技术Background technique
铅酸电池，其出现已超百年，拥有着成熟的电池技术，占据着汽车启动电瓶、电动自行车、UPS等储能领域的绝对市场份额。铅酸电池虽然循环使用寿命较低，能量密度也相对较低，但却拥有价格非常低廉，性价比非常高的优点。因此，近些年来，镍氢电池、锂离子电池、钠硫电池、液流电池等，均无法在储能领域取代铅酸电池。The lead-acid battery has been in existence for more than 100 years and has mature battery technology, occupying an absolute market share in the energy storage fields such as automobile starter batteries, electric bicycles and UPS. Although the lead-acid battery has a low cycle life and a relatively low energy density, it has the advantages of very low price and very high cost performance. Therefore, in recent years, nickel-metal hydride batteries, lithium-ion batteries, sodium-sulfur batteries, and liquid flow batteries have failed to replace lead-acid batteries in the field of energy storage.
近几年来出现一种新型水系二次电池。该二次电池的正极能够基于金属离子进行可逆的脱出-嵌入反应，负极能够基于金属离子进行可逆的还原沉积-氧化溶解反应，电解液含有参与正极脱出-嵌入反应的金属离子和参与负极沉积-溶解反应的金属离子。A new type of water-based secondary battery has appeared in recent years. The positive electrode of the secondary battery is capable of reversible elution-embedding reaction based on metal ions, and the negative electrode can perform reversible reduction deposition-oxidation dissolution reaction based on metal ions, and the electrolyte contains metal ions participating in the positive electrode extraction-embedding reaction and participating in negative electrode deposition- Dissolve the reacted metal ions.
该类型电池的电解液为水溶液，不存在类似锂离子电池中有机电解液的安全隐患，且对环境友好，成本较低，能量密度高。因此，该类型电池非常有希望成为替代铅酸电池的下一代储能电池，具有极大的应用价值。The electrolyte of this type of battery is an aqueous solution, and there is no safety hazard similar to the organic electrolyte in a lithium ion battery, and it is environmentally friendly, low in cost, and high in energy density. Therefore, this type of battery is very promising as a next-generation energy storage battery to replace lead-acid batteries, which has great application value.
该类型电池的参与负极沉积-溶解反应的金属离子可以为锌离子，此时负极活性物质为金属锌，然而这类负极活性物质在水溶液中充放电时存在枝晶、腐蚀、析氢等问题，从而使电池的循环性能、充放电容量受到影响。因此，现有技术需要进一步改善。The metal ion participating in the negative electrode deposition-dissolution reaction of the battery of the type may be zinc ion. At this time, the negative electrode active material is metal zinc. However, such negative electrode active material has problems such as dendrite, corrosion, hydrogen evolution and the like when charged and discharged in the aqueous solution, thereby The cycle performance and charge and discharge capacity of the battery are affected. Therefore, the prior art needs further improvement.
另外，这种水系二次电池主要采用LiMn2O4作为正极活性物质，但其导电性能还不能满足要求。In addition, such a water-based secondary battery mainly uses LiMn 2 O 4 as a positive electrode active material, but its electrical conductivity is not satisfactory.
通常的，导电碳黑作为导电剂用于增加电池电极的导电性。电极通常由电极活性材料，导电剂(如乙炔黑)和聚合物粘结剂混合而成。然而，炭黑纳米颗粒在远程导电性能上显示不足，从而限制了电池的倍率性能。Generally, conductive carbon black is used as a conductive agent to increase the conductivity of the battery electrode. The electrode is usually a mixture of an electrode active material, a conductive agent such as acetylene black, and a polymer binder. However, carbon black nanoparticles show insufficient performance in remote conductivity, thereby limiting the rate performance of the battery.
石墨烯是目前已知的最薄、强度最大的材料，其具有比表面积大，导电导热性能优良，热膨胀系数低等突出特点。因此石墨烯在储能领域、热传导领域以及高强材料领域具有极大的运用前景。其中之一就是作为二次电池的导电剂。Graphene is the thinnest and strongest material known at present, and has outstanding characteristics such as large specific surface area, excellent electrical and thermal conductivity, and low thermal expansion coefficient. Therefore, graphene has great application prospects in the field of energy storage, heat conduction and high-strength materials. One of them is a conductive agent as a secondary battery.
石墨烯的研究和应用对它的大批量、低成本制备提出了需求。目前石墨烯的制备方法主要有微机械剥离法、石墨插层、还原氧化石墨和气相沉积等 方法。目前石墨烯的制备方法仍存在一些问题。如微机械剥离法制备的石墨烯内部缺陷较多，质量较差。化学气相沉积法制备的石墨烯具有较高的质量，但是得到的多为二维片状石墨，石墨片之间界面电阻不利于电子长程、快速传输。The research and application of graphene puts forward a demand for its high-volume, low-cost preparation. At present, the preparation methods of graphene mainly include micro mechanical peeling method, graphite intercalation, reduced graphite oxide and vapor deposition. method. At present, there are still some problems in the preparation of graphene. Graphene prepared by micromechanical stripping method has many internal defects and poor quality. The graphene prepared by chemical vapor deposition has higher quality, but most of the obtained graphite is two-dimensional flake graphite. The interface resistance between the graphite flakes is not conducive to long-term electron transfer and fast transmission.
发明内容Summary of the invention
虽然已经尝试了多种电解液的添加剂，但是对于现有的电池来说，目前的添加剂仍然存在无法充分地解决负极活性物质在水系溶液中的枝晶、腐蚀、析氢等问题。Although various electrolyte additives have been tried, the conventional additives still have problems in that the dendrites, corrosion, hydrogen evolution, and the like of the negative electrode active material in the aqueous solution cannot be sufficiently solved.
鉴于现有技术中存在的技术问题，本发明的目的是提供一种能够用于电池的电解液，该电解液可以有效地抑制负极，尤其是锌负极的枝晶、腐蚀、析氢等问题。In view of the technical problems existing in the prior art, an object of the present invention is to provide an electrolyte which can be used for a battery, which can effectively suppress problems such as dendrites, corrosion, hydrogen evolution and the like of the negative electrode, particularly the zinc negative electrode.
本发明提供一种电池用电解液，所述电解液包括充放电过程中在负极能够还原沉积为金属且该金属能可逆氧化溶解的负极金属离子；参与电池正极反应的正极离子；以及添加剂离子，所述添加剂离子选自Na、Mg、Al、NH4 +、Ni、Co、Ce、Fe、Pb或Mn离子中的至少一种，并且所述添加剂离子不同于负极金属离子和正极离子。The invention provides an electrolyte for a battery, which comprises a negative electrode metal ion which can be reduced and deposited as a metal in the negative electrode during charging and discharging and which can be reversibly oxidized and dissolved; a positive electrode ion which participates in a positive electrode reaction of the battery; and an additive ion, The additive ion is selected from at least one of Na, Mg, Al, NH 4 + , Ni, Co, Ce, Fe, Pb or Mn ions, and the additive ion is different from the negative electrode metal ion and the positive electrode ion.
优选的，添加剂离子在电解液中的浓度为0.001M～8M。Preferably, the concentration of the additive ions in the electrolyte is from 0.001 M to 8 M.
优选的，添加剂离子Mg离子在电解液中的浓度为0.001M～0.5M。Preferably, the concentration of the additive ion Mg ions in the electrolyte is from 0.001 M to 0.5 M.
优选的，添加剂离子Ce、Fe、Mn、Pb和/或Co离子在电解液中的浓度为0.1M～8M。Preferably, the concentration of the additive ions Ce, Fe, Mn, Pb and/or Co ions in the electrolyte is from 0.1 M to 8 M.
优选的，所述负极金属离子为锌离子。Preferably, the negative metal ion is a zinc ion.
优选的，所述正极离子选自锂离子、钠离子或者镁离子。Preferably, the positive electrode ion is selected from the group consisting of lithium ion, sodium ion or magnesium ion.
优选的，所述负极金属离子为锌离子，所述正极离子为溴离子或钒离子。Preferably, the negative electrode metal ion is a zinc ion, and the positive electrode ion is a bromide ion or a vanadium ion.
优选的，所述电解液的pH为2～8。Preferably, the electrolyte has a pH of 2-8.
优选的，所述电解液还包括溶剂，所述溶剂为水和/或醇。Preferably, the electrolyte further includes a solvent which is water and/or an alcohol.
本发明还一种电池，所述电池包括：正极、负极以及所述的电解液。The present invention also provides a battery comprising: a positive electrode, a negative electrode, and the electrolyte.
优选的，所述正极包括正极材料，所述正极材料包括正极活性物质和正极导电剂，所述正极导电剂为石墨烯，所述石墨烯由单层或者多层石墨烯结构单元组成，所述石墨烯具有孔状结构，孔径分布范围为2-10nm。Preferably, the positive electrode includes a positive electrode material, the positive electrode material includes a positive electrode active material and a positive electrode conductive agent, the positive electrode conductive agent is graphene, and the graphene is composed of a single layer or a plurality of graphene structural units, Graphene has a pore-like structure with a pore size distribution ranging from 2 to 10 nm.
优选的，所述石墨烯的平均孔径范围为3-5nm。Preferably, the graphene has an average pore diameter ranging from 3-5 nm.
优选的，所述石墨烯的尺寸范围为200-1000nm。Preferably, the graphene has a size ranging from 200 to 1000 nm.
优选的，所述石墨烯的比表面积为300-2000m2/g。Preferably, the graphene has a specific surface area of 300 to 2000 m 2 /g.
本发明还提供一种电池组，包括若干个电池，电池如前所述。 The present invention also provides a battery pack comprising a plurality of batteries as described above.
根据本发明，电池的循环性能、充放电容量获得了进一步的提升，此外，使用了本发明的电解液的电池，具有良好的容量保持率，放电电容损失低，并且能够实现深度放电。According to the present invention, the cycle performance and the charge and discharge capacity of the battery are further improved. Further, the battery using the electrolytic solution of the present invention has a good capacity retention ratio, low discharge capacitance loss, and enables deep discharge.
通过在电解液中添加给定的添加剂离子或者添加给定浓度的给定添加剂离子，采用这种新的电解液可以有效地抑制负极(例如锌负极)的枝晶、腐蚀、析氢等问题，从而获得电池循环性能，充放电容量得到提高，并意外地发现能够实现电池的深度放电。By adding a given additive ion to the electrolyte or adding a given concentration of a given additive ion, the use of the new electrolyte can effectively suppress dendrites, corrosion, hydrogen evolution and the like of the negative electrode (for example, a zinc negative electrode). The battery cycle performance was obtained, the charge and discharge capacity was improved, and it was unexpectedly found that deep discharge of the battery can be achieved.
本发明还提供一种具有多孔结构的石墨烯，石墨烯具有良好的长程导电子和导离子性能。The present invention also provides a graphene having a porous structure, which has good long-range conductor and ion-conducting properties.
本发明提供了一种石墨烯，所述石墨烯由单层或者多层石墨烯结构单元组成，所述石墨烯具有孔状结构，孔径分布范围为2-10nm。The present invention provides a graphene composed of a single layer or a plurality of graphene structural units, the graphene having a pore-like structure with a pore size distribution ranging from 2 to 10 nm.
优选的，所述石墨烯的平均孔径范围为3-5nm。Preferably, the graphene has an average pore diameter ranging from 3-5 nm.
优选的，所述石墨烯的尺寸范围为200-1000nm。Preferably, the graphene has a size ranging from 200 to 1000 nm.
优选的，所述石墨烯的比表面积为300-2000m2/g。Preferably, the specific surface area of the graphene 300-2000m 2 / g.
本发明还提供了一种正极，所述正极包括正极材料，所述正极材料包括正极活性物质和正极导电剂，所述正极导电剂包括所述的石墨烯。The present invention also provides a positive electrode comprising a positive electrode material, the positive electrode material comprising a positive electrode active material and a positive electrode conductive agent, the positive electrode conductive agent comprising the graphene.
本发明还提供了一种电池，包括正极、负极以及设置在所述正极和负极之间的电解液，所述正极包括正极材料，所述正极材料包括正极活性物质和正极导电剂，所述正极导电剂包括如上所述的石墨烯。The present invention also provides a battery comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, the positive electrode including a positive electrode material, the positive electrode material including a positive electrode active material and a positive electrode conductive agent, the positive electrode The conductive agent includes graphene as described above.
优选的，所述正极导电剂占所述正极材料的质量百分含量范围为2％-15％。Preferably, the positive electrode conductive agent accounts for 2%-15% by mass of the positive electrode material.
优选的，所述正极活性物质在所述正极材料的质量百分含量范围为80-90％。Preferably, the positive electrode active material has a mass percentage in the positive electrode material ranging from 80 to 90%.
优选的，所述正极活性物质能够可逆脱出-嵌入第一金属离子，所述第一金属离子选自锂离子、钠离子或镁离子；所述电解液包括电解质以及溶剂水；所述电解质至少能够电离出所述第一金属离子和第二金属离子；所述第一金属离子在充放电过程中在所述正极能够可逆脱出-嵌入；所述第二金属离子在充电过程中在所述负极还原沉积为第二金属，所述第二金属在放电过程中氧化溶解为第二金属离子；所述第二金属离子选自锰离子、铁离子、铜离子、锌离子、铬离子、镍离子、锡离子或铅离子；所述电解质的阴离子包括硫酸根离子、氯离子、醋酸根离子、硝酸根离子，甲酸根离子和烷基磺酸根离子中的一种或几种；所述电解液的pH值为2-8；所述电池还包括位于正极和负 极之间的隔膜。Preferably, the positive active material is capable of reversibly extracting-embeding a first metal ion, the first metal ion being selected from lithium ions, sodium ions or magnesium ions; the electrolyte comprising an electrolyte and solvent water; Electrolyzing the first metal ion and the second metal ion; the first metal ion is reversibly deintercalated-embedded in the positive electrode during charge and discharge; and the second metal ion is reduced in the negative electrode during charging Deposited as a second metal, the second metal is oxidatively dissolved into a second metal ion during discharge; the second metal ion is selected from the group consisting of manganese ions, iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin An ion or a lead ion; the anion of the electrolyte includes one or more of a sulfate ion, a chloride ion, an acetate ion, a nitrate ion, a formate ion, and an alkylsulfonate ion; a pH of the electrolyte 2-8; the battery also includes a positive and negative The diaphragm between the poles.
本发明还提供了一种如上所述的石墨烯的制备方法，所述石墨烯通过化学气相沉积法制备，所述制备方法包括以下步骤：The present invention also provides a method for preparing graphene as described above, wherein the graphene is prepared by a chemical vapor deposition method, and the preparation method comprises the following steps:
步骤一：通过化学气相沉积使碳源气体在具有多孔结构的催化剂上生长石墨烯形成石墨烯/催化剂复合结构；所述催化剂选自氧化镁、氧化锌、氧化铜或氧化铝；Step 1: growing a graphene to form a graphene/catalyst composite structure by chemical vapor deposition on a catalyst having a porous structure; the catalyst is selected from the group consisting of magnesium oxide, zinc oxide, copper oxide or aluminum oxide;
步骤二：通过刻蚀去除复合结构中的催化剂，得到所述石墨烯。Step 2: removing the catalyst in the composite structure by etching to obtain the graphene.
优选的，在所述步骤一中，化学气相沉积反应器在惰性气体氛围下加热，达到预设温度后，将所述催化剂放入所述化学气相沉积反应器中，并向所述化学气相沉积反应器中通入碳源气体。Preferably, in the first step, the chemical vapor deposition reactor is heated under an inert gas atmosphere, and after reaching a preset temperature, the catalyst is placed in the chemical vapor deposition reactor, and the chemical vapor deposition is performed. A carbon source gas is introduced into the reactor.
优选的，所述预设温度范围为820-875℃。Preferably, the preset temperature ranges from 820 to 875 °C.
优选的，所述碳源气体流量为500-1000毫升/分，所述通入时间为5-30分。Preferably, the carbon source gas has a flow rate of 500-1000 ml/min, and the pass-in time is 5-30 minutes.
优选的，所述碳源气体为乙炔、乙烯或甲烷。Preferably, the carbon source gas is acetylene, ethylene or methane.
优选的，在所述步骤二中，将所述石墨烯/催化剂复合结构放入盐酸中进行刻蚀以去除所述催化剂。Preferably, in the second step, the graphene/catalyst composite structure is placed in hydrochloric acid for etching to remove the catalyst.
本发明提供的石墨烯具有均匀的连续的多孔网络结构和亲水性，具有优异的长程的导电子和导离子能力。将其作为导电剂应用在水系二次电池中，电池具有明显改善的倍率性能和循环性能。同时，本发明还提供的制备石墨烯的方法简单，制备石墨烯所采用的流化床易于中试放大，制备方法具有商业化应用前景。The graphene provided by the invention has a uniform continuous porous network structure and hydrophilicity, and has excellent long-range conductivity and ion-conducting ability. It is used as a conductive agent in an aqueous secondary battery, and the battery has significantly improved rate performance and cycle performance. At the same time, the method for preparing graphene provided by the invention is simple, and the fluidized bed used for preparing graphene is easy to be pilot-scaled, and the preparation method has commercial application prospects.
附图说明DRAWINGS
图1-3是电池B1、B3和B4的充放电循环性能图；Figure 1-3 is a graph of charge and discharge cycle performance of batteries B1, B3 and B4;
图4是电池B5在0.2C倍率下的充放电曲线；Figure 4 is a charge and discharge curve of the battery B5 at a rate of 0.2 C;
图5是电池B5在0.2C倍率下在0.5～2.1V电压区间内的充放电曲线；5 is a charge and discharge curve of the battery B5 in a voltage range of 0.5 to 2.1 V at a 0.2 C rate;
图6是电池B5在3C倍率下的充放电循环性能图；Figure 6 is a graph showing the charge and discharge cycle performance of the battery B5 at a 3C rate;
图7是电池S1在3C倍率下的充放电循环性能图。Fig. 7 is a graph showing the charge and discharge cycle performance of the battery S1 at a 3C rate.
图8分别为材料PG、RGO和EG的扫描电镜和透射电镜照片；Figure 8 is a scanning electron microscope and transmission electron micrograph of the materials PG, RGO and EG;
图9为正极C1、C2和C3的扫描电镜照片；Figure 9 is a scanning electron micrograph of the positive electrodes C1, C2 and C3;
图10为电池LiMn2O4/PG、LiMn2O4/RGO和LiMn2O4/EG的倍率性能图；Figure 10 is a graph showing the rate performance of the batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO, and LiMn 2 O 4 /EG;
图11为电池LiMn2O4/PG、LiMn2O4/RGO和LiMn2O4/EG的循环性能图；Figure 11 is a cycle performance diagram of the batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO, and LiMn 2 O 4 /EG;
图12为电池LiMn2O4/PG、LiMn2O4/RGO和LiMn2O4/EG循环300次后 的电化学阻抗谱图。Fig. 12 is an electrochemical impedance spectrum of the battery LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG after 300 cycles.
具体实施方式detailed description
下面结合具体实施方式对本发明进行详细的说明。The invention will now be described in detail in connection with the specific embodiments.
本发明提供一种电解液，其包括电解质和溶剂；其中所述电解质包括：充放电过程中在负极能够还原沉积为金属且该金属能可逆氧化溶解的负极金属离子；参与正极反应的正极离子；以及添加剂离子，所述添加剂离子选自Na、Mg、Al、NH4 +、Ni、Co、Ce、Fe、Pb或Mn离子中的至少一种，并且所述添加剂离子不同于上述负极金属离子和正极离子。The present invention provides an electrolyte comprising an electrolyte and a solvent; wherein the electrolyte comprises: a negative electrode metal ion capable of being reducedly deposited as a metal in the negative electrode during charging and discharging and capable of reversible oxidative dissolution of the metal; and a positive electrode ion participating in the positive electrode reaction; And an additive ion selected from at least one of Na, Mg, Al, NH 4 + , Ni, Co, Ce, Fe, Pb or Mn ions, and the additive ion is different from the above negative electrode metal ion and Positive ion.
在一个方面中，本发明的添加剂离子在电解液中的浓度为0.001M～8M(mol/L)。In one aspect, the additive ions of the present invention have a concentration in the electrolyte of from 0.001 M to 8 M (mol/L).
作为添加剂离子的所述Al离子在电解液中的浓度为0.001M～8M(mol/L)，优选为0.01M～5M，进一步优选0.1M～2M。The concentration of the Al ion as the additive ion in the electrolytic solution is 0.001 M to 8 M (mol/L), preferably 0.01 M to 5 M, and more preferably 0.1 M to 2 M.
作为添加剂离子的所述Na、Mg和/或Ni在电解液中的浓度为0.001M以上且小于1M，优选为0.5M以下，更优选0.3M以下，更优选0.2M以下，更优选0.1M以下，更优选0.09M以下，更优选0.08M以下，更优选0.07M以下，更优选0.06M以下，更优选0.05M以下，以及优选0.001M以上，优选0.005M以上，优选0.01M以上。The concentration of the Na, Mg, and/or Ni as the additive ion in the electrolytic solution is 0.001 M or more and less than 1 M, preferably 0.5 M or less, more preferably 0.3 M or less, further preferably 0.2 M or less, and more preferably 0.1 M or less. More preferably, it is 0.09 M or less, more preferably 0.08 M or less, more preferably 0.07 M or less, still more preferably 0.06 M or less, further preferably 0.05 M or less, and preferably 0.001 M or more, preferably 0.005 M or more, and preferably 0.01 M or more.
作为添加剂离子的所述Ce、Fe、Mn、Pb和/或Co在电解液中的浓度为大于0.1M且8M以下，优选在0.2M以上，更优选在0.3M以上，更优选在0.4M以上，更优选在0.5M以上，更优选在0.8M以上，且优选在8M以下，更优选在5M以下，更优选在2M以下。The concentration of the Ce, Fe, Mn, Pb, and/or Co as an additive ion in the electrolytic solution is more than 0.1 M and 8 M or less, preferably 0.2 M or more, more preferably 0.3 M or more, and still more preferably 0.4 M or more. It is more preferably 0.5 M or more, still more preferably 0.8 M or more, and is preferably 8 M or less, more preferably 5 M or less, and still more preferably 2 M or less.
作为添加剂离子的所述NH4 +离子在电解液中的浓度为0.25M以上且8M以下，优选为0.25～4M，进一步优选为0.5～2M。The concentration of the NH 4 + ion as an additive ion in the electrolytic solution is 0.25 M or more and 8 M or less, preferably 0.25 to 4 M, and more preferably 0.5 to 2 M.
当添加剂离子采用Na、Mg、K或Ni时，此时的正极离子和负极金属离子与添加剂离子不同，即均不选自Na、Mg、K和/或Ni。When the additive ions are Na, Mg, K or Ni, the positive electrode ions and the negative electrode metal ions at this time are different from the additive ions, that is, they are not selected from Na, Mg, K and/or Ni.
当添加剂离子采用Ce、Fe、Mn、Pb或Co时，此时的正极离子和负极金属离子与添加剂离子不同，即均不选自Ce、Fe、Mn、Pb和/或Co。When the additive ions are Ce, Fe, Mn, Pb or Co, the positive electrode ions and the negative electrode metal ions at this time are different from the additive ions, that is, they are not selected from Ce, Fe, Mn, Pb and/or Co.
此外，在本发明中作为添加剂离子在电解液中的浓度是指当该离子作为添加剂离子时在电解液中的浓度。此外，如果使用上述两种或两种以上添加剂离子时，上述浓度是指每种添加剂离子各自的浓度。Further, the concentration of the additive ion in the electrolytic solution in the present invention means the concentration in the electrolytic solution when the ion is used as the additive ion. Further, if two or more of the above additive ions are used, the above concentrations refer to the respective concentrations of each of the additive ions.
添加剂离子来源于向电解液中添加的无机添加剂，无机添加剂选自钠化合物、镁化合物、铝化合物、铵化合物、镍化合物、钴化合物、铈化合物、铁化合物、铅化合物以及锰化合物中的一种或者两种或者更多。 The additive ion is derived from an inorganic additive added to the electrolyte, and the inorganic additive is selected from the group consisting of a sodium compound, a magnesium compound, an aluminum compound, an ammonium compound, a nickel compound, a cobalt compound, a cerium compound, an iron compound, a lead compound, and a manganese compound. Or two or more.
在本发明中采用溶剂的目的是用来溶解包括负极金属离子，正极离子、以及添加剂离子在内的电解质成分，并使得电解质在溶剂中电离，最终在电解液中生成可自由移动的阳离子和阴离子。The purpose of using a solvent in the present invention is to dissolve an electrolyte component including a negative electrode metal ion, a positive electrode ion, and an additive ion, and ionize the electrolyte in a solvent to finally generate freely movable cations and anions in the electrolyte. .
本发明的溶剂优选为水和/或醇。其中醇包括但不限于甲醇或乙醇。The solvent of the present invention is preferably water and/or an alcohol. Among them, alcohols include, but are not limited to, methanol or ethanol.
电解液中的负极金属离子，在充放电过程中在负极能够还原沉积为金属，放电过程中该金属可逆氧化为金属离子。即在电池充电时，电解液中的负极金属离子还原成金属，沉积在负极上；在电池放电时，该金属氧化成为金属离子并从负极上溶出，进入电解液。The negative electrode metal ion in the electrolyte can be reduced and deposited as a metal in the negative electrode during charge and discharge, and the metal can be reversibly oxidized into a metal ion during discharge. That is, when the battery is charged, the negative electrode metal ions in the electrolyte are reduced to metal and deposited on the negative electrode; when the battery is discharged, the metal is oxidized into metal ions and eluted from the negative electrode to enter the electrolyte.
优选地，负极金属离子为锌离子。Preferably, the negative metal ion is a zinc ion.
负极金属离子在电解液中的浓度范围为0.5-15M。负极金属离子以氯酸盐、硫酸盐、硝酸盐、醋酸盐、甲酸盐、磷酸盐等形式存在于电解液中。优选，负极金属离子以硫酸盐、醋酸盐或硫酸盐和醋酸盐的混合物的形式存在于电解液中。The concentration of the negative electrode metal ion in the electrolyte ranges from 0.5 to 15 M. The negative electrode metal ion is present in the electrolyte in the form of a chlorate, a sulfate, a nitrate, an acetate, a formate or a phosphate. Preferably, the negative electrode metal ion is present in the electrolyte in the form of a sulfate, acetate or a mixture of sulfate and acetate.
电解液还包括参与正极反应的正极离子。该正极离子可以是在电池正极发生嵌入和脱出的金属离子或在充放电过程中参与正极氧化还原反应的离子。The electrolyte also includes positive electrode ions that participate in the positive electrode reaction. The positive electrode ion may be a metal ion that is inserted and removed at the positive electrode of the battery or an ion that participates in the positive electrode redox reaction during charge and discharge.
在本发明的实施方式一中，该正极离子是在电池正极发生嵌入和脱出的金属离子。在电池充电时，电解液中的该正极离子嵌入到正极材料中；电池放电时，充电时嵌入的该离子又从正极材料中脱出到电解液中。优选地，正极离子为锂离子。此时，正极离子在电解液中的浓度范围为0.1-30M。In the first embodiment of the present invention, the positive electrode ion is a metal ion which is inserted and removed at the positive electrode of the battery. When the battery is charged, the positive electrode ions in the electrolyte are embedded in the positive electrode material; when the battery is discharged, the ions embedded during charging are again released from the positive electrode material into the electrolyte. Preferably, the positive electrode ion is a lithium ion. At this time, the concentration of the positive electrode ions in the electrolytic solution ranges from 0.1 to 30 M.
该正极离子以氯酸盐、硫酸盐、硝酸盐、醋酸盐、甲酸盐、磷酸盐等形式存在于电解液中。优选的，正极离子以硫酸盐、醋酸盐或硫酸盐和醋酸盐的混合物的形式存在于电解液中。The positive electrode ion is present in the electrolyte in the form of a chlorate, a sulfate, a nitrate, an acetate, a formate or a phosphate. Preferably, the positive electrode ion is present in the electrolyte in the form of a sulfate, acetate or a mixture of a sulfate and an acetate.
在本发明的实施方式二中，该正极离子是在充放电过程中参与正极氧化还原反应的离子。在电池充电时，电解液中的该离子被氧化；电池放电时，充电时被氧化的活性物质又被还原。正极离子选自溴离子、钒离子中的一种或者两种。此时，当正极离子是溴离子的时候，其浓度可以为例如0.5M～20M。In Embodiment 2 of the present invention, the positive electrode ion is an ion that participates in a positive electrode redox reaction during charge and discharge. When the battery is charged, the ions in the electrolyte are oxidized; when the battery is discharged, the oxidized active material is reduced during charging. The positive electrode ion is selected from one or both of a bromide ion and a vanadium ion. At this time, when the positive electrode ion is a bromide ion, the concentration thereof may be, for example, 0.5 M to 20 M.
在一优选的实施方式中，电解液中包括锌离子和锂离子。随着充放电的进行，锌离子在负极发生沉积-溶解，锂离子在正极发生嵌入-脱出。In a preferred embodiment, zinc ions and lithium ions are included in the electrolyte. As the charge and discharge progresses, zinc ions are deposited-dissolved at the negative electrode, and lithium ions are intercalated-extracted at the positive electrode.
在一优选的实施方式中，电解液中包括溴离子和锌离子，随着充放电的进行，锌离子在负极发生沉积-溶解，溴离子在正极发生氧化-还原反应。In a preferred embodiment, the electrolyte includes bromide ions and zinc ions. As the charge and discharge progress, zinc ions are deposited-dissolved at the negative electrode, and the bromide ions undergo an oxidation-reduction reaction at the positive electrode.
而在本发明中，通过在上述浓度范围内添加特定的添加剂离子，可以显著地抑制负极金属离子(例如锌离子)在水溶液中充放电时存在的枝晶、腐蚀 以及析氢等问题，从而显著地改善了电池的循环性能和充放电容量，并意外地发现了还可以实现电池的深度放电。In the present invention, by adding a specific additive ion in the above concentration range, dendrite and corrosion existing when the negative electrode metal ion (for example, zinc ion) is charged and discharged in an aqueous solution can be remarkably suppressed. As well as problems such as hydrogen evolution, the cycle performance and charge and discharge capacity of the battery are remarkably improved, and it has been unexpectedly found that deep discharge of the battery can also be achieved.
具体来说，通过在上述给定浓度范围添加给定的添加剂离子，可以显著地提高电池的开路电压和容量保持率，放电容量损失减小到未添加给定的添加剂离子的电池的70％左右。此外，在50个循环、100个循环和150个循环之后的容量保持率均可以保持在较高的水平，尤其是150个循环后的容量保持率显著高于不使用添加剂的情况，使得循环保持率可以始终保持在约95％以上。Specifically, by adding a given additive ion in the above-mentioned given concentration range, the open circuit voltage and capacity retention rate of the battery can be remarkably improved, and the discharge capacity loss is reduced to about 70% of the battery to which no given additive ion is added. . In addition, the capacity retention rate after 50 cycles, 100 cycles and 150 cycles can be maintained at a high level, especially after 150 cycles, the capacity retention rate is significantly higher than without the use of additives, so that the cycle is maintained. The rate can always be maintained above about 95%.
此外，在高库伦倍率的情况下，当循环稳定后，会保持数百个循环(超过1000个循环)其放电容量均非常稳定，波动小于5％，即容量保持率始终在95％左右。而未添加添加剂的情况在300个循环后，放电容量仅为初始放电容量的80％左右。说明添加了本发明的添加剂离子，蓄电池的循环寿命与稳定性得到大幅提高。本发明人通过观察电池的内部结构发现，由于添加剂了本发明的添加剂离子，在下述实施例的蓄电池中，直到电池进行充放电800个循环之前，均未出现在负极的枝晶的现象，而在未添加这样的添加剂离子的对比例中，通常在100～300个充放电循环的过程中就会出现在锌负极的枝晶，从而严重影响的容量。In addition, in the case of high Coulomb magnification, when the cycle is stabilized, it will remain for hundreds of cycles (more than 1000 cycles), and its discharge capacity is very stable, and the fluctuation is less than 5%, that is, the capacity retention rate is always around 95%. In the case where no additive was added, after 300 cycles, the discharge capacity was only about 80% of the initial discharge capacity. It is indicated that the additive ions of the present invention are added, and the cycle life and stability of the battery are greatly improved. The inventors have found that by adding the additive ions of the present invention, in the battery of the following embodiment, the dendrite of the negative electrode does not appear until the battery is charged and discharged for 800 cycles, by observing the internal structure of the battery. In the comparative example in which such an additive ion is not added, dendrites of the zinc negative electrode are usually present during the course of 100 to 300 charge and discharge cycles, thereby seriously affecting the capacity.
可见，采用了本发明的电解液制备的电池，其负极的腐蚀、析氢和枝晶等不良反应得到了良好地抑制，从而解决了本领域难以解决的问题，改善了电池的循环性能和充放电容量。It can be seen that the battery prepared by using the electrolyte of the invention has good suppression of adverse reactions such as corrosion, hydrogen evolution and dendrite of the negative electrode, thereby solving the problems difficult to be solved in the field and improving the cycle performance and charge and discharge capacity of the battery. .
此外，利用本发明的电解液时，还意外地发现可以实现电池的深度放电，通常采用本发明中涉及的电池(如下所述)时，通常仅可以放电到例如1.4V左右，而通过采用本发明的上述电解液，可以实现深度放电，放电到0.5V左右。推测这也是由于抑制了负极的腐蚀、析氢和枝晶等问题而带来的显著的效果。Further, when the electrolytic solution of the present invention is used, it has been unexpectedly found that deep discharge of the battery can be realized. Generally, when the battery according to the present invention (described below) is used, it is generally only possible to discharge to, for example, about 1.4 V, and by using this. The above electrolyte solution of the invention can achieve deep discharge and discharge to about 0.5V. It is presumed that this is also a remarkable effect by suppressing problems such as corrosion of the negative electrode, hydrogen evolution, and dendrites.
优选本发明电解液中的添加剂离子为镁离子或锰离子中的一种或者两种。优选地，提供镁离子或锰离子的无机添加剂选自它们各自的氧化物、醋酸盐、碳酸盐、硫酸盐、硝酸盐中的一种或者几种。在一优选的实施方式中，镁化合物为硫酸镁，锰化合物为硫酸锰。采用镁离子或锰离子的电解液与其他的添加剂离子相比，可以更进一步改善电池的循环性能和充放电容量，并可以实现电池的深度放电。Preferably, the additive ion in the electrolyte of the present invention is one or both of magnesium ion or manganese ion. Preferably, the inorganic additive providing magnesium or manganese ions is selected from one or more of their respective oxides, acetates, carbonates, sulfates, nitrates. In a preferred embodiment, the magnesium compound is magnesium sulfate and the manganese compound is manganese sulfate. Compared with other additive ions, the electrolyte using magnesium ion or manganese ion can further improve the cycle performance and charge and discharge capacity of the battery, and can realize deep discharge of the battery.
无机添加剂加入电解液的方法，根据电解液或隔膜的不同情况，可以选择不同的加入方式。加入方式包括但不限于直接加入电解液中，或者以悬浮液滴加在隔膜上。更优选地，将无机添加剂直接加入到电解液中，然后将电 解液滴到隔膜上。The method of adding the inorganic additive to the electrolyte may be selected according to different conditions of the electrolyte or the separator. The means of addition include, but is not limited to, direct addition to the electrolyte, or addition of the suspension droplets to the membrane. More preferably, the inorganic additive is directly added to the electrolyte and then charged Decompose the droplet onto the diaphragm.
为了使电池性能更加的优化，在本发明的实施方式一或二中，本发明的电解液pH值范围优选3～7。pH的范围可以通过缓冲剂来调节。电解液的pH过高，可能会影响电解液中锌离子的浓度，电解液的pH过低，则会加剧电极材料的腐蚀。而将电解液的pH范围保持在3～7，既可以有效保证电解液中各种离子的浓度，还可以避免电解腐蚀。In order to further optimize battery performance, in the first or second embodiment of the present invention, the pH of the electrolyte of the present invention is preferably in the range of 3 to 7. The pH range can be adjusted by a buffer. If the pH of the electrolyte is too high, it may affect the concentration of zinc ions in the electrolyte. If the pH of the electrolyte is too low, the corrosion of the electrode material may be aggravated. Keeping the pH range of the electrolyte at 3 to 7 can effectively ensure the concentration of various ions in the electrolyte and avoid electrolytic corrosion.
本发明还涉及一种电池，其包括正极、负极和上述电解液。The present invention also relates to a battery comprising a positive electrode, a negative electrode, and the above electrolyte.
本发明的实施方式一的正极可以包括正极集流体和正极材料，正极材料包括正极活性物质。The positive electrode of Embodiment 1 of the present invention may include a positive electrode current collector and a positive electrode material, and the positive electrode material includes a positive electrode active material.
在本发明的实施方式一的正极中，对所述正极集流体没有特殊限制，本领域技术人员可根据需要适当选择。正极集流体通常作为电子传导和收集的载体，不参与电化学反应，即在电池工作电压范围内，正极集流体能够稳定的存在于电解液中而基本不发生副反应，从而保证电池具有稳定的循环性能。正极集流体的大小可根据电池的使用用途来确定。例如，如果在要求高能量密度的大型电池中使用，则可以使用面积大的正极集流体。对正极集流体的厚度没有特殊限制，通常为1～100μm左右。对于正极集流体的形状没有特别地限定，例如可以为长方形或圆形。对构成正极集流体的材料没有特殊限制，例如，可以采用金属、合金、碳基材料等。具体地，碳基材料可以是选自玻璃碳、石墨、碳毡、碳纤维、或具有3D双连续结构的导电材料中的一种。其中，具有3D双连续结构的导电材料包括但不仅限于泡沫碳。石墨包括但不仅限于石墨箔和石墨板。金属可以是选自Al、Fe、Cu、Pb、Ti、Cr、Mo、Co、Ag或经过钝化处理的上述金属中的一种。合金可以是选自不锈钢、铝合金、Ni合金、Ti合金、Cu合金、Co合金、Ti-Pt合金、Pt-Rh合金或经过钝化处理的上述合金中的一种。不锈钢包括不锈钢箔或不锈钢网，具体地，不锈钢的型号可以是但不限于300系列的不锈钢，如不锈钢304、316、316L或316P。铝合金的型号可以是但不限于6000系列的铝合金，如铝合金6061。In the positive electrode of the first embodiment of the present invention, the positive electrode current collector is not particularly limited, and those skilled in the art can appropriately select them as needed. The positive current collector usually acts as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction, that is, within the operating voltage range of the battery, the positive current collector can be stably present in the electrolyte without substantially causing side reactions, thereby ensuring stable battery. Cycle performance. The size of the cathode current collector can be determined according to the use of the battery. For example, if used in a large battery requiring high energy density, a large positive current collector can be used. The thickness of the positive electrode current collector is not particularly limited and is usually about 1 to 100 μm. The shape of the positive electrode current collector is not particularly limited, and may be, for example, a rectangle or a circle. The material constituting the cathode current collector is not particularly limited, and for example, a metal, an alloy, a carbon-based material, or the like can be used. Specifically, the carbon-based material may be one selected from the group consisting of glassy carbon, graphite, carbon felt, carbon fiber, or a conductive material having a 3D double continuous structure. Among them, the conductive material having a 3D double continuous structure includes, but is not limited to, foamed carbon. Graphite includes, but is not limited to, graphite foil and graphite sheets. The metal may be one selected from the group consisting of Al, Fe, Cu, Pb, Ti, Cr, Mo, Co, Ag or the above-mentioned metal which has been passivated. The alloy may be one selected from the group consisting of stainless steel, aluminum alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti-Pt alloy, Pt-Rh alloy, or passivated alloy. The stainless steel includes a stainless steel foil or a stainless steel mesh. Specifically, the stainless steel may be, but not limited to, a 300 series stainless steel such as stainless steel 304, 316, 316L or 316P. The model of the aluminum alloy may be, but not limited to, an aluminum alloy of the 6000 series, such as an aluminum alloy 6061.
在本发明的实施方式一的正极中，所述正极集流体上形成有正极活性物质层。所述正极活性物质层可以形成于所述正极集流体的一面，也可以形成于所述正极集流体的两面。在本发明的实施方式一正极中，对所述正极活性物质没有特殊限定，只要其能可逆脱出-嵌入金属离子即可，本领域技术人员可根据需要适当选择。In the positive electrode according to the first embodiment of the present invention, the positive electrode active material layer is formed on the positive electrode current collector. The positive electrode active material layer may be formed on one surface of the positive electrode current collector or may be formed on both surfaces of the positive electrode current collector. In the positive electrode of the first embodiment of the present invention, the positive electrode active material is not particularly limited as long as it can reversibly elute-embed metal ions, and those skilled in the art can appropriately select them as needed.
在所述金属离子为锂离子的情况下，作为所述正极活性物质可以包含选自以通式Li1+xMnyMzOk(其中，-1≤x≤0.5，1≤y≤2.5，0≤z≤0.5，3≤k≤6，M为 选自Na、Li、Co、Mg、Ti、Cr、V、Zn、Zr、Si、Al中的至少一种)表示的具有尖晶石结构的化合物、以通式Li1+xMyM′zM″cO2+n(其中，-1＜x≤0.5，0≤y≤1，0≤z≤1，0≤c≤1，-0.2≤n≤0.2，M，M′，M″分别选自Ni、Mn、Co、Mg、Ti、Cr、V、Zn、Zr、Si或Al中的至少一种)表示的具有层状结构的化合物、以及以通式LixM1-yM′y(XO4)n(其中，0＜x≤2，0≤y≤0.6，1≤n≤1.5，M选自Fe、Mn、V或Co，M′选自Mg、Ti、Cr、V或Al的中至少一种，X选自S、P或Si中的至少一种)表示的具有橄榄石结构的化合物中的一种或两种以上。优选地，所述正极活性物质可以包含选自LiMn2O4、LiFePO4和LiCoO2中一种或两种以上。In the case where the metal ion is a lithium ion, the positive electrode active material may be selected from the group consisting of the general formula Li 1+x Mn y M z O k (wherein -1≤x≤0.5, 1≤y≤2.5 , 0 ≤ z ≤ 0.5, 3 ≤ k ≤ 6, M is a spinel represented by at least one selected from the group consisting of Na, Li, Co, Mg, Ti, Cr, V, Zn, Zr, Si, and Al) a compound of the structure, having the general formula Li 1+x M y M′ z M′′ c O 2+n (wherein −1<x≤0.5, 0≤y≤1, 0≤z≤1, 0≤c≤1 , -0.2 ≤ n ≤ 0.2, M, M', M" are respectively selected from at least one of Ni, Mn, Co, Mg, Ti, Cr, V, Zn, Zr, Si or Al) a compound of the structure, and a formula of Li x M 1-y M' y (XO 4 )n (where 0 < x ≤ 2 , 0 ≤ y ≤ 0.6, 1 ≤ n ≤ 1.5, M is selected from Fe, Mn, V or Co, M' is at least one selected from the group consisting of Mg, Ti, Cr, V or Al, and X is at least one selected from the group consisting of at least one of S, P or Si) Two or more. Preferably, the cathode active material may contain one or more selected from the group consisting of LiMn 2 O 4 , LiFePO 4 and LiCoO 2 .
在所述金属离子为钠离子的情况下，作为所述正极活性物质，可以列举出例如：作为层状氧化物类材料的钠铁复合氧化物(NaFeO2)、钠钴复合氧化物(NaCoO2)、钠铬复合氧化物(NaCrO2)、钠锰复合氧化物(NaMnO2)、钠镍复合氧化物(NaNiO2)、钠镍钛复合氧化物(NaNi1/2Ti1/2O2)、钠镍锰复合氧化物(NaNi1/2Mn1/2O2)、钠铁锰复合氧化物(Na2/3Fe1/3Mn2/3O2)、钠镍钴锰复合氧化物(NaNi1/3Co1/3Mn1/3O2)、它们的固溶体、非化学计量组成的化合物等。此外，还可以列举出钠锰复合氧化物(NaMn2O4)、钠镍锰复合氧化物(NaNi1/2Mn3/2O2)等。此外，还可以列举出例如作为橄榄石类材料的钠铁磷酸化合物(NaFePO4)、钠锰磷酸化合物(NaMnPO4)、钠钴磷酸化合物(NaCoPO4)等。此外，还可以列举出例如作为氟化橄榄石类材料的Na2FePO4F、Na2MnPO4F、Na2CoPO4F等。In the case where the metal ion is a sodium ion, the positive electrode active material may, for example, be a sodium iron composite oxide (NaFeO 2 ) or a sodium cobalt composite oxide (NaCoO 2 ) as a layered oxide material. ), sodium chromium composite oxide (NaCrO 2 ), sodium manganese composite oxide (NaMnO 2 ), sodium nickel composite oxide (NaNiO 2 ), sodium nickel titanium composite oxide (NaNi 1/2 Ti 1/2 O 2 ) , sodium nickel manganese composite oxide (NaNi 1/2 Mn 1/2 O 2 ), sodium iron manganese composite oxide (Na 2/3 Fe 1/3 Mn 2/3 O 2 ), sodium nickel cobalt manganese composite oxide (NaNi 1/3 Co 1/3 Mn 1/3 O 2 ), a solid solution thereof, a compound having a non-stoichiometric composition, and the like. Further, examples thereof include a sodium manganese composite oxide (NaMn 2 O 4 ), a sodium nickel manganese composite oxide (NaNi 1/2 Mn 3/2 O 2 ), and the like. Further, for example, a sodium iron phosphate compound (NaFePO 4 ), a sodium manganese phosphate compound (NaMnPO 4 ), a sodium cobalt phosphate compound (NaCoPO 4 ), or the like, which is an olivine-based material, may be mentioned. Further, for example, Na 2 FePO 4 F, Na 2 MnPO 4 F, Na 2 CoPO 4 F, or the like, which is a fluorinated olivine-based material, may be mentioned.
在目前电池工业中，几乎所有正极活性物质都会经过掺杂、包覆等改性处理。但掺杂，包覆改性等手段造成材料的化学通式表达复杂，如LiMn2O4已经不能够代表目前广泛使用的“锰酸锂”的通式，而应该以通式Li1+xMnyMzOk为准，广泛地包括经过各种改性的LiMn2O4正极活性物质。同样的，LiFePO4以及LiCoO2也应该广泛地理解为包括经过各种掺杂、包覆等改性的，通式分别符合LixM1-yM′y(XO4)n和Li1+xMyM′zM″cO2+n的正极活性物质。In the current battery industry, almost all positive active materials are subjected to modification treatment such as doping and coating. However, the chemical formula expression of the material is complicated by doping, coating modification, etc., such as LiMn 2 O 4 can not represent the general formula of "manganese manganate" which is widely used, but should be of the general formula Li 1+x The Mn y M z O k is broadly included, and variously modified LiMn 2 O 4 positive electrode active materials are widely included. Similarly, LiFePO 4 and LiCoO 2 should also be broadly understood to include modifications through various doping, cladding, etc., which are in accordance with Li x M 1-y M' y (XO 4 )n and Li 1+, respectively. a positive electrode active material of x M y M' z M" c O 2+n .
实施方式一的正极活性物质为能可逆脱出-嵌入锂离子的物质时，优选可以选用如LiMn2O4、LiFePO4、LiCoO2、LiMxPO4、LiMxSiOy(其中M为一种变价金属)等化合物。此外，正极活性物质为能可逆脱出-嵌入钠离子的物质时，优选可以选用NaVPO4F等。正极，还包括负载正极活性物质的正极集流体，正极集流体的材料选自碳基材料、金属或合金中的一种。When the positive electrode active material of the first embodiment is a substance capable of reversibly extracting-intercalating lithium ions, it is preferable to use, for example, LiMn 2 O 4 , LiFePO 4 , LiCoO 2 , LiM x PO 4 , LiM x SiO y (where M is a variable price) Compounds such as metals). Further, when the positive electrode active material is a substance capable of reversibly eluting-embeding sodium ions, NaVPO4F or the like is preferably used. The positive electrode further includes a positive electrode current collector supporting the positive electrode active material, and the material of the positive electrode current collector is selected from one of a carbon-based material, a metal or an alloy.
在制备实施方式一的正极时，除了正极活性物质之外，根据实际情况，正极材料还包括正极导电剂和正极粘结剂来提升正极的性能。 In the preparation of the positive electrode of the first embodiment, in addition to the positive electrode active material, the positive electrode material further includes a positive electrode conductive agent and a positive electrode binder to enhance the performance of the positive electrode, depending on the actual situation.
正极导电剂选自导电聚合物、活性碳、石墨烯、碳黑、石墨、碳纤维、金属纤维、金属粉末、以及金属薄片中的一种或多种。The positive electrode conductive agent is selected from one or more of a conductive polymer, activated carbon, graphene, carbon black, graphite, carbon fiber, metal fiber, metal powder, and metal flake.
优选的，正极导电剂为石墨烯，石墨烯由单层或者多层石墨烯结构单元组成，石墨烯具有孔状结构，孔径分布范围为2-10nm。Preferably, the positive electrode conductive agent is graphene, the graphene is composed of a single layer or a plurality of graphene structural units, and the graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm.
具体的，石墨烯的平均孔径范围为3-5nm，在一个优选的实施例中，石墨烯的平均孔径范围为4nm。Specifically, the graphene has an average pore diameter ranging from 3-5 nm. In a preferred embodiment, the graphene has an average pore diameter ranging from 4 nm.
具体的，石墨烯的尺寸范围为200-1000nm。氧化石墨烯的尺寸是指氧化石墨烯片层的平均长宽值，实际尺寸由于氧化石墨烯片层的柔性会有一定的偏差。Specifically, the size of graphene ranges from 200 to 1000 nm. The size of the graphene oxide refers to the average length and width of the graphene oxide sheet layer, and the actual size may be deviated due to the flexibility of the graphene oxide sheet layer.
具体的，石墨烯的比表面积为300-2000m2/g。Specifically, the graphene has a specific surface area of 300 to 2000 m 2 /g.
本发明提供的正极导电剂石墨烯是一种具有均匀的连续的多孔网络结构和较大比表面积的石墨烯材料，即多孔石墨烯材料，其具有优异的长程的导电子和导离子能力。同时，相比于剥离石墨烯的憎水性，本发明中的石墨烯具有很好的亲水性能，多孔结构结合亲水性，使得石墨烯作为导电剂应用在水系二次电池时，能够很好的容纳水系电解液，使水系电解液和活性物质可以充分接触，这种石墨烯作为导电材料在水系电池中具有很好的应用前景。The positive electrode conductive agent graphene provided by the present invention is a graphene material having a uniform continuous porous network structure and a large specific surface area, that is, a porous graphene material having excellent long-range conductivity and ion-conducting ability. Meanwhile, compared with the hydrophobicity of the exfoliated graphene, the graphene in the present invention has a good hydrophilic property, and the porous structure is combined with hydrophilicity, so that graphene can be used as a conductive agent in a water-based secondary battery. The water-based electrolyte is contained so that the aqueous electrolyte and the active material can be sufficiently contacted, and the graphene has a good application prospect as a conductive material in an aqueous battery.
正极粘结剂可以选自聚乙烯氧化物、聚丙烯氧化物、聚丙烯腈、聚酰亚胺、聚酯、聚醚、氟化聚合物、聚二乙烯基聚乙二醇、聚乙二醇二丙烯酸酯、聚乙二醇二甲基丙烯酸中的一种、或上述聚合物的混合物及衍生物。更优选地，正极粘结剂选自聚四氟乙烯(PTFE)、聚偏氟乙烯(PVDF)或丁苯橡胶(SBR)。The positive electrode binder may be selected from the group consisting of polyethylene oxide, polypropylene oxide, polyacrylonitrile, polyimide, polyester, polyether, fluorinated polymer, polydivinyl polyethylene glycol, polyethylene glycol. One of diacrylate, polyethylene glycol dimethacrylate, or a mixture and derivative of the above polymers. More preferably, the positive electrode binder is selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or styrene butadiene rubber (SBR).
本发明提供了一种石墨烯，石墨烯由单层或者多层石墨烯结构单元组成，石墨烯具有孔状结构，孔径分布范围为2-10nm。具体的，石墨烯的平均孔径范围为3-5nm，在一个优选的实施例中，石墨烯的平均孔径范围为4nm。The present invention provides a graphene composed of a single layer or a plurality of graphene structural units, and the graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm. Specifically, the graphene has an average pore diameter ranging from 3-5 nm. In a preferred embodiment, the graphene has an average pore diameter ranging from 4 nm.
具体的，石墨烯的尺寸范围为200-1000nm。氧化石墨烯的尺寸是指氧化石墨烯片层的平均长宽值，实际尺寸由于氧化石墨烯片层的柔性会有一定的偏差。Specifically, the size of graphene ranges from 200 to 1000 nm. The size of the graphene oxide refers to the average length and width of the graphene oxide sheet layer, and the actual size may be deviated due to the flexibility of the graphene oxide sheet layer.
具体的，石墨烯的比表面积为300-2000m2/g。Specifically, the graphene has a specific surface area of 300 to 2000 m 2 /g.
本发明提供的石墨烯是一种具有均匀的连续的多孔网络结构和较大比表面积的石墨烯材料，即多孔石墨烯材料，其具有优异的长程的导电子和导离子能力。同时，相比于剥离石墨烯的憎水性，本发明中的石墨烯具有很好的亲水性能，多孔结构结合亲水性，使得石墨烯作为导电剂应用在水系二次电 池时，能够很好的容纳水系电解液，使水系电解液和活性物质可以充分接触，这种石墨烯作为导电材料在水系电池中具有很好的应用前景。The graphene provided by the present invention is a graphene material having a uniform continuous porous network structure and a large specific surface area, that is, a porous graphene material having excellent long-range conductivity and ion-conducting ability. At the same time, compared with the hydrophobicity of the exfoliated graphene, the graphene in the invention has good hydrophilic properties, and the porous structure combines hydrophilicity, so that graphene is used as a conductive agent in the water system secondary electricity. When the pool is used, the water-based electrolyte can be well accommodated, so that the aqueous electrolyte and the active material can be sufficiently contacted. This graphene has a good application prospect as a conductive material in water-based batteries.
在本发明实施方式二中，正极为碳电极或复合氧化物电极碳电极，也可以为石墨电极。In the second embodiment of the present invention, the positive electrode is a carbon electrode or a composite oxide electrode carbon electrode, and may be a graphite electrode.
另外，正极也可以由基体和在其上附着的含有正极活性物质的膏体组成。此时的正极活性物质例如可以是溴化锌，基体为碳毡、石墨毡、碳纸或碳布的多孔导电碳材料。Further, the positive electrode may also be composed of a substrate and a paste containing a positive electrode active material attached thereto. The positive electrode active material at this time may be, for example, zinc bromide, and the matrix is a porous conductive carbon material of carbon felt, graphite felt, carbon paper or carbon cloth.
电池的负极发生电化学反应的物质为负极反应金属，负极反应金属能够氧化溶解为负极金属离子且负极金属离子能可逆还原沉积为负极反应金属。The substance in which the negative electrode of the battery electrochemically reacts is a negative electrode reaction metal, and the negative electrode reaction metal can be oxidized and dissolved into a negative electrode metal ion and the negative electrode metal ion can be reversibly reduced and deposited as a negative electrode reaction metal.
在实施方式一或二中，负极包括负极集流体，并且负极集流体仅作为电子传导和收集的载体，不参与电化学反应。此时，负极集流体为用于负极充放电的载体。负极集流体的材料选自金属Ni、Cu、Ag、Pb、Mn、Sn、Fe、Al或经过钝化处理的上述金属中的至少一种，或者单质硅，或者碳基材料，其中，碳基材料包括石墨材料，比如商业化的石墨压制的箔，其中石墨所占的重量比例范围为90～100％。负极集流体的材料还可以选自不锈钢或经钝化处理的不锈钢。不锈钢包括但不仅限于不锈钢网和不锈钢箔，同样的，不锈钢的型号可以是300系列的不锈钢，如不锈钢304或者不锈钢316或者不锈钢316L。In the first or second embodiment, the anode includes the anode current collector, and the anode current collector serves only as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction. At this time, the anode current collector is a carrier for charging and discharging the anode. The material of the anode current collector is selected from at least one of metal Ni, Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal, or elemental silicon, or carbon-based material, wherein carbon-based material Materials include graphite materials such as commercial graphite pressed foils in which the weight ratio of graphite ranges from 90 to 100%. The material of the anode current collector may also be selected from stainless steel or passivated stainless steel. Stainless steel includes, but is not limited to, stainless steel mesh and stainless steel foil. Similarly, stainless steel models can be 300 series stainless steel, such as stainless steel 304 or stainless steel 316 or stainless steel 316L.
在一个优选实施方式中，负极除了负极集流体，还包括负载在负极集流体上的负极活性物质。此时，负极活性物质为用于负极充放电的载体。负极活性物质为锌。In a preferred embodiment, the negative electrode includes a negative electrode active material supported on the negative electrode current collector in addition to the negative electrode current collector. At this time, the negative electrode active material is a carrier for charging and discharging the negative electrode. The negative electrode active material is zinc.
在一个优选实施方式中，直接采用锌片作为负极，锌片既作为负极集流体，同时也为负极活性物质。此时，锌片为用于负极充放电的载体。In a preferred embodiment, a zinc sheet is directly used as a negative electrode, and the zinc sheet serves as both a negative electrode current collector and a negative electrode active material. At this time, the zinc sheet is a carrier for charging and discharging the negative electrode.
在本发明中，电池可以不含隔膜。当然，为了提供更好的安全性能，优选在电解液中位于正极与负极之间还设有隔膜。隔膜可以避免其他意外因素造成的正负极相连而造成的短路。In the present invention, the battery may be free of a separator. Of course, in order to provide better safety performance, it is preferred to provide a separator between the positive electrode and the negative electrode in the electrolyte. The diaphragm can avoid short circuits caused by the connection of positive and negative electrodes caused by other unexpected factors.
本发明的隔膜没有特殊要求，只要是允许电解液通过且电子绝缘的隔膜即可。有机系锂离子电池采用的各种隔膜，均可以适用于本发明。隔膜还可以是微孔陶瓷隔板等其他材料。The separator of the present invention is not particularly required as long as it is a separator which allows the electrolyte to pass through and is electrically insulated. Various separators used in organic lithium ion batteries can be applied to the present invention. The separator may also be other materials such as microporous ceramic separators.
本发明提供了一种石墨烯，石墨烯由单层或者多层石墨烯结构单元组成，石墨烯具有孔状结构，孔径分布范围为2-10nm。The present invention provides a graphene composed of a single layer or a plurality of graphene structural units, and the graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm.
具体的，石墨烯的平均孔径范围为3-5nm，在一个优选的实施例中，石墨烯的平均孔径范围为4nm。 Specifically, the graphene has an average pore diameter ranging from 3-5 nm. In a preferred embodiment, the graphene has an average pore diameter ranging from 4 nm.
具体的，石墨烯的尺寸范围为200-1000nm。氧化石墨烯的尺寸是指氧化石墨烯片层的平均长宽值，实际尺寸由于氧化石墨烯片层的柔性会有一定的偏差。Specifically, the size of graphene ranges from 200 to 1000 nm. The size of the graphene oxide refers to the average length and width of the graphene oxide sheet layer, and the actual size may be deviated due to the flexibility of the graphene oxide sheet layer.
具体的，石墨烯的比表面积为300-2000m2/g。Specifically, the graphene has a specific surface area of 300 to 2000 m 2 /g.
本发明提供的石墨烯是一种具有均匀的连续的多孔网络结构和较大比表面积的石墨烯材料，即多孔石墨烯材料，其具有优异的长程的导电子和导离子能力。同时，相比于剥离石墨烯的憎水性，本发明中的石墨烯具有很好的亲水性能，多孔结构结合亲水性，使得石墨烯作为导电剂应用在水系二次电池时，能够很好的容纳水系电解液，使水系电解液和活性物质可以充分接触，这种石墨烯作为导电材料在水系电池中具有很好的应用前景。The graphene provided by the present invention is a graphene material having a uniform continuous porous network structure and a large specific surface area, that is, a porous graphene material having excellent long-range conductivity and ion-conducting ability. Meanwhile, compared with the hydrophobicity of the exfoliated graphene, the graphene in the present invention has a good hydrophilic property, and the porous structure is combined with hydrophilicity, so that graphene can be used as a conductive agent in a water-based secondary battery. The water-based electrolyte is contained so that the aqueous electrolyte and the active material can be sufficiently contacted, and the graphene has a good application prospect as a conductive material in an aqueous battery.
本发明还提供了一种石墨烯的制备方法，石墨烯通过一步化学气相沉积法(CVD)制备而得。The invention also provides a method for preparing graphene, which is prepared by one-step chemical vapor deposition (CVD).
制备方法包括以下步骤：步骤一：通过化学气相沉积使碳源气体在催化剂上生长石墨烯形成石墨烯/催化剂复合结构；步骤二：通过刻蚀去除复合结构中的催化剂，得到所述石墨烯。The preparation method comprises the following steps: Step 1: The carbon source gas is grown on the catalyst by chemical vapor deposition to form a graphene/catalyst composite structure; Step 2: removing the catalyst in the composite structure by etching to obtain the graphene.
优选的，在步骤一中，化学气相沉积反应器在惰性气体氛围下加热，达到预设温度后，将催化剂放入到化学气相沉积反应器中，并向反应器中通入碳源气体。这样设置，可以更好的节约工艺时间和惰性气体，降低制备成本。Preferably, in the first step, the chemical vapor deposition reactor is heated under an inert gas atmosphere, and after reaching a preset temperature, the catalyst is placed in a chemical vapor deposition reactor, and a carbon source gas is introduced into the reactor. This arrangement can save process time and inert gas better and reduce the production cost.
催化剂具有多孔结构，选自氧化镁、氧化锌、氧化铜或氧化铝。制得的石墨烯具有孔状结构，孔径分布范围为2-10nm，石墨烯的平均孔径范围为3-5nm。多孔的催化剂和多孔石墨烯有着相似的孔分布情况，因为多孔石墨烯的生长是以多孔的催化剂为模板进行的。The catalyst has a porous structure selected from the group consisting of magnesium oxide, zinc oxide, copper oxide or aluminum oxide. The obtained graphene has a pore structure with a pore size distribution ranging from 2 to 10 nm, and graphene has an average pore diameter ranging from 3-5 nm. Porous catalysts and porous graphene have similar pore distributions because the growth of porous graphene is carried out using a porous catalyst as a template.
制得的石墨烯的尺寸范围为200-1000nm，比表面积为300-2000m2/g。The obtained graphene has a size ranging from 200 to 1000 nm and a specific surface area of from 300 to 2000 m 2 /g.
优选的，预设温度范围为820-875℃。在该温度范围下，制备的石墨烯具有更加均匀、连续的网络多孔结构，同时孔径大小相当，材料一致性能好。Preferably, the preset temperature range is 820-875 °C. At this temperature range, the prepared graphene has a more uniform and continuous network porous structure, and the pore size is equivalent, and the material has good uniformity.
碳源气体为乙炔、乙烯或甲烷。碳源气体流量为500-1000毫升/分，通入时间为5-30分钟。合适的碳源气体流量有助于碳源气体均匀的热解并生长在氧化镁上，使最终制备的石墨烯具有均匀的多孔结构。The carbon source gas is acetylene, ethylene or methane. The carbon source gas flow rate is 500-1000 ml/min, and the access time is 5-30 minutes. A suitable carbon source gas flow rate contributes to uniform pyrolysis of the carbon source gas and growth on the magnesium oxide, so that the finally prepared graphene has a uniform porous structure.
在步骤二中，将石墨烯/催化剂复合结构放入盐酸中进行刻蚀以去除催化剂。In step two, the graphene/catalyst composite structure is placed in hydrochloric acid for etching to remove the catalyst.
在一个具体的制备方法的实施例中，以氧化镁作为催化剂，垂直设置的石英管式炉作为化学气相沉积反应器，将石英管式炉在氩气氛围中加热，一 旦温度达到预设温度875℃，将氧化镁催化剂投入到反应器中，通入碳源气体甲烷，通入甲烷的气体流量为800毫升/分，通入10分钟。随后冷却至室温，取出所得的材料，通过盐酸洗涤刻蚀去除氧化镁，将产物过滤并在80℃干燥过夜，即制得多孔的石墨烯。In an embodiment of a specific preparation method, a quartz tube furnace which is vertically disposed is used as a chemical vapor deposition reactor using magnesium oxide as a catalyst, and a quartz tube furnace is heated in an argon atmosphere. Once the temperature reached the preset temperature of 875 ° C, the magnesia catalyst was put into the reactor, the carbon source gas methane was introduced, and the gas flow rate of methane was 800 ml/min, and it was passed for 10 minutes. Subsequently, the mixture was cooled to room temperature, the obtained material was taken out, magnesium oxide was removed by washing with hydrochloric acid, and the product was filtered and dried at 80 ° C overnight to obtain porous graphene.
相比于其他微机械剥离法和氧化石墨还原法，本发明提供的化学气相沉积法制备石墨烯工艺简单，制备的石墨烯具有多孔结构，亲水性好以及具有优异的导电子和导离子性能。同时生产石墨烯所采用的化学气相沉积流化床易于放大，本发明提供的制备方法具有良好的商业应用前景。Compared with other micro-mechanical stripping method and graphite oxide reduction method, the present invention provides a simple process for preparing graphene by chemical vapor deposition, and the prepared graphene has a porous structure, good hydrophilicity and excellent conductivity and conductivity. . The chemical vapor deposition fluidized bed used for the simultaneous production of graphene is easy to amplify, and the preparation method provided by the invention has good commercial application prospects.
本发明还提供了一种导电剂，导电剂包括上面所述的石墨烯，石墨烯为多孔结构，具有优异的导电子和导离子能力。The invention also provides a conductive agent comprising the graphene described above, the graphene is a porous structure, and has excellent conductivity and ion guiding ability.
本发明还提供了一种正极，正极包括正极材料，正极材料包括正极活性物质和正极导电剂，正极导电剂包括如上所述的石墨烯。The present invention also provides a positive electrode comprising a positive electrode material, the positive electrode material comprising a positive electrode active material and a positive electrode conductive agent, and the positive electrode conductive agent comprising graphene as described above.
本发明还提供了一种电池，包括正极、负极以及设置在正极和负极之间的电解液，正极包括正极材料，正极材料包括正极活性物质和正极导电剂，正极导电剂包括如上所述的石墨烯。The present invention also provides a battery comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, the positive electrode including a positive electrode material, the positive electrode material including a positive electrode active material and a positive electrode conductive agent, and the positive electrode conductive agent including the graphite as described above Alkene.
正极活性物质参与正极反应，并且能够可逆脱出-嵌入第一金属离子。优选的，第一金属离子选自锂离子、钠离子或镁离子。The positive active material participates in the positive electrode reaction and is capable of reversibly extracting-embedding the first metal ion. Preferably, the first metal ion is selected from the group consisting of lithium ions, sodium ions or magnesium ions.
正极活性物质可以是符合通式Li1+xMnyMzOk的能够可逆脱出-嵌入锂离子的尖晶石结构的化合物，其中，-1≤x≤0.5，1≤y≤2.5，0≤z≤0.5，3≤k≤6，M选自Na、Li、Co、Mg、Ti、Cr、V、Zn、Zr、Si、Al中的至少一种。优选的，正极活性物质含有LiMn2O4。更优选的，正极活性物质含有经过掺杂或包覆改性的LiMn2O4。The positive electrode active material may be a compound capable of reversible elution-intercalation lithium ion-doped spinel structure conforming to the general formula Li 1+x Mn y M z O k , wherein -1≤x≤0.5, 1≤y≤2.5,0 ≤ z ≤ 0.5, 3 ≤ k ≤ 6, M is at least one selected from the group consisting of Na, Li, Co, Mg, Ti, Cr, V, Zn, Zr, Si, and Al. Preferably, the positive electrode active material contains LiMn 2 O 4 . More preferably, the positive electrode active material contains doped or coated modified LiMn 2 O 4 .
正极活性物质可以是符合通式Li1+xMyM′zM″cO2+n的能够可逆脱出-嵌入锂离子的层状结构的化合物，其中，-1<x≤0.5，0≤y≤1，0≤z≤1，0≤c≤1，-0.2≤n≤0.2，M，M′，M″分别选自Ni、Mn、Co、Mg、Ti、Cr、V、Zn、Zr、Si或Al的中至少一种。The positive electrode active material may be a compound capable of reversibly deintercalating-intercalating lithium ion in a layered structure conforming to the general formula Li 1+x M y M′ z M′′ c O 2+n , wherein −1<x≤0.5, 0≤ y ≤ 1, 0 ≤ z ≤ 1, 0 ≤ c ≤ 1, -0.2 ≤ n ≤ 0.2, M, M', M" are respectively selected from Ni, Mn, Co, Mg, Ti, Cr, V, Zn, Zr At least one of Si, Si or Al.
正极活性物质还可以是符合通式LixM1-yM′y(XO4)n的能够可逆脱出-嵌入锂离子的橄榄石结构的化合物，其中，0<x≤2，0≤y≤0.6，1≤n≤1.5，M选自Fe、Mn、V或Co，M′选自Mg、Ti、Cr、V或Al的中至少一种，X选自S、P或Si中的至少一种。The positive electrode active material may also be a compound having a olivine structure capable of reversibly extracting-intercalating lithium ions according to the general formula Li x M 1-y M' y (XO 4 ) n , wherein 0<x≤2, 0≤y≤ 0.6, 1≤n≤1.5, M is selected from Fe, Mn, V or Co, and M' is at least one selected from the group consisting of Mg, Ti, Cr, V or Al, and X is at least one selected from the group consisting of S, P or Si. Kind.
优选的，正极活性物质选自LiMn2O4、LiFePO4或LiCoO2中一种或几种。Preferably, the positive electrode active material is one or more selected from the group consisting of LiMn 2 O 4 , LiFePO 4 or LiCoO 2 .
在目前电池工业中，几乎所有正极活性物质都会经过掺杂、包覆等改性 处理。但掺杂，包覆改性等手段造成材料的化学通式表达复杂，如LiMn2O4已经不能够代表目前广泛使用的“锰酸锂”的通式，而应以通式Li1+xMnyMzOk为准，广泛地包括经过各种改性的LiMn2O4正极活性物质。同样的，LiFePO4以及LiCoO2也应该广泛地理解为包括经过各种掺杂、包覆等改性的，通式分别符合LixM1-yM′y(XO4)n和Li1+xMyM′zM″cO2+n的正极活性物质。In the current battery industry, almost all positive active materials are modified by doping, coating, and the like. However, the chemical formula expression of the material is complicated by doping, coating modification, etc., such as LiMn 2 O 4 can not represent the general formula of "manganese manganate" which is widely used, but should be of the general formula Li 1+x The Mn y M z O k is broadly included, and variously modified LiMn 2 O 4 positive electrode active materials are widely included. Similarly, LiFePO 4 and LiCoO 2 should also be broadly understood to include modifications through various doping, cladding, etc., which are in accordance with Li x M 1-y M' y (XO 4 ) n and Li 1+, respectively. a positive electrode active material of x M y M' z M" c O 2+n .
正极活性物质为锂离子脱出-嵌入化合物时，可以选用如LiMn2O4、LiFePO4、LiCoO2、LiMxPO4、LiMxSiOy(其中M为一种变价金属)等化合物。When the positive electrode active material is a lithium ion elution-embedded compound, a compound such as LiMn 2 O 4 , LiFePO 4 , LiCoO 2 , LiM x PO 4 , LiM x SiO y (wherein M is a variable valence metal) may be selected.
此外，可脱出-嵌入钠离子的化合物NaVPO4F，可脱出-嵌入镁离子的化合物MgMxOy(其中M为一种金属，0.5<x<3，2<y<6)以及具有类似功能，能够脱出-嵌入离子或官能团的化合物都可以作为本发明电池的正极活性物质，因此，本发明并不局限于锂离子电池。In addition, the NaDCO 4 F, a compound capable of eluting-inserting sodium ions, can be extracted-embedded into a magnesium ion compound MgM x O y (where M is a metal, 0.5<x<3, 2<y<6) and has similar functions. A compound capable of deintercalating-embeding an ion or a functional group can be used as a positive electrode active material of the battery of the present invention, and therefore, the present invention is not limited to a lithium ion battery.
优选的，正极导电剂占正极材料的质量百分含量范围为2％-15％，正极活性物质在正极材料的质量百分含量范围为80-90％，这样，在保证正极材料具有优异的导电子和导离子性能的同时，使正极具有较高的容量。更加优选的，正极导电剂占正极材料的质量百分含量范围为3％-10％。Preferably, the positive electrode conductive agent accounts for 2% to 15% by mass of the positive electrode material, and the positive electrode active material has a mass percentage of 80% to 90% of the positive electrode material, thereby ensuring excellent conductivity of the positive electrode material. At the same time of electron and ion conductivity, the positive electrode has a higher capacity. More preferably, the positive electrode conductive agent accounts for 3% to 10% by mass of the positive electrode material.
在具体的实施例中，制备正极时，正极材料中除了正极活性物质和导电剂之外，通常可能还会添加正极粘结剂来提升正极的性能。示例的，正极粘结剂选自聚四氟乙烯(PTFE)、聚偏氟乙烯(PVDF)或丁苯橡胶(SBR)。In a specific embodiment, when the positive electrode is prepared, in addition to the positive electrode active material and the conductive agent, a positive electrode binder may be added to the positive electrode material to improve the performance of the positive electrode. Illustratively, the positive electrode binder is selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or styrene butadiene rubber (SBR).
正极活性物质负载在正极集流体上，正极集流体作为电子传导和收集的载体，不参与电化学反应，即在电池工作电压范围内，正极集流体能够稳定的存在于电解液中而基本不发生副反应，从而保证电池具有稳定的循环性能。The positive active material is supported on the positive current collector, and the positive current collector acts as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction, that is, in the operating voltage range of the battery, the positive current collector can stably exist in the electrolyte without substantially occurring. Side reaction to ensure stable cycle performance of the battery.
正极集流体的选材和构成有多种选择。There are many options for the material selection and composition of the positive current collector.
选择一Choose one
正极集流体的材料选自碳基材料、金属或合金中的一种。The material of the cathode current collector is selected from one of a carbon-based material, a metal or an alloy.
碳基材料选自玻璃碳、石墨箔、石墨片、泡沫碳、碳毡、碳布、碳纤维中的一种。在具体的实施方式中，正极集流体为石墨，如商业化的石墨压制的箔，其中石墨所占的重量比例范围为90-100％。The carbon-based material is selected from the group consisting of glassy carbon, graphite foil, graphite flakes, foamed carbon, carbon felt, carbon cloth, and carbon fiber. In a specific embodiment, the cathode current collector is graphite, such as a commercial graphite pressed foil, wherein the weight ratio of graphite ranges from 90 to 100%.
金属包括Ni、Al、Fe、Cu、Pb、Ti、Cr、Mo、Co、Ag或经过钝化处理的上述金属中的一种。The metal includes one of Ni, Al, Fe, Cu, Pb, Ti, Cr, Mo, Co, Ag or the above-mentioned metal which has been passivated.
合金包括不锈钢、碳钢、Al合金、Ni合金、Ti合金、Cu合金、Co合金、Ti-Pt合金、Pt-Rh合金或上述金属经过钝化处理中的一种。The alloy includes one of stainless steel, carbon steel, Al alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti-Pt alloy, Pt-Rh alloy or passivation treatment of the above metal.
不锈钢包括不锈钢网、不锈钢箔，不锈钢的型号包括但不仅限于不锈钢 304或者不锈钢316或者不锈钢316L中的一种。Stainless steel includes stainless steel mesh, stainless steel foil, stainless steel models include but are not limited to stainless steel One of 304 or stainless steel 316 or stainless steel 316L.
优选的，对正极集流体进行钝化处理，主要目的是，使正极集流体的表面形成一层钝化的氧化膜，从而在电池充放电过程中，能起到稳定的收集和传导电子的作用，而不会参与电池反应，保证电池性能稳定。正极集流体钝化处理方法包括化学钝化处理或电化学钝化处理。Preferably, the passivation treatment is performed on the positive current collector, and the main purpose is to form a passivated oxide film on the surface of the positive current collector, thereby stably collecting and conducting electrons during charging and discharging of the battery. , and will not participate in the battery reaction to ensure stable battery performance. The positive current collector passivation treatment method includes a chemical passivation treatment or an electrochemical passivation treatment.
化学钝化处理包括通过氧化剂氧化正极集流体，使正极集流体表面形成钝化膜。氧化剂选择的原则为氧化剂能使正极集流体表面形成一层钝化膜而不会溶解正极集流体。氧化剂选自但不仅限于浓硝酸或硫酸高铈(Ce(SO4)2)。The chemical passivation treatment includes oxidizing the cathode current collector by an oxidizing agent to form a passivation film on the surface of the cathode current collector. The principle of oxidant selection is that the oxidant can form a passivation film on the surface of the positive current collector without dissolving the positive current collector. The oxidizing agent is selected from, but not limited to, concentrated nitric acid or sorghum sulfate (Ce(SO 4 ) 2 ).
电化学钝化处理包括对正极集流体进行电化学氧化或对含有正极集流体的电池进行充放电处理，使正极集流体表面形成钝化膜。The electrochemical passivation treatment comprises electrochemically oxidizing the cathode current collector or charging and discharging the battery containing the cathode current collector to form a passivation film on the surface of the cathode current collector.
选择二Choose two
优选的，正极集流体上还包覆有导电膜，其中正极集流体的选材可参见选择一，这里就不再赘述。Preferably, the positive current collector is further coated with a conductive film, wherein the selection of the positive current collector can be referred to the selection one, and details are not described herein again.
导电膜的选材满足在水系电解液中可以稳定存在、不溶于电解液、不发生溶胀、高电压不能被氧化、易于加工成致密、不透水并且导电的要求。一方面，导电膜对正极集流体可以起到保护作用，避免水系电解液对正极集流体的腐蚀。另一方面，有利于降低正极片与正极集流体之间的接触内阻，提高电池的能量。The selection of the conductive film satisfies the requirement that it can be stably present in the aqueous electrolyte, is insoluble in the electrolyte, does not swell, the high voltage cannot be oxidized, and is easily processed into a dense, watertight, and electrically conductive material. On the one hand, the conductive film can protect the positive current collector from corrosion of the positive current collector by the aqueous electrolyte. On the other hand, it is advantageous to reduce the contact internal resistance between the positive electrode sheet and the positive electrode current collector, and to increase the energy of the battery.
优选的，导电膜的厚度为10μm～2mm，导电膜不仅能够有效的起到保护正极集流体的作用，而且有利于降低正极活性物质与正极集流体之间的接触内阻，提高电池的能量。Preferably, the conductive film has a thickness of 10 μm to 2 mm, and the conductive film can not only effectively protect the positive electrode current collector, but also reduce the contact internal resistance between the positive electrode active material and the positive electrode current collector, thereby improving the energy of the battery.
正极集流体具有相对设置的第一面和第二面，优选的，正极集流体的第一面和第二面均包覆有导电膜。The cathode current collector has opposite first and second faces. Preferably, the first surface and the second surface of the cathode current collector are coated with a conductive film.
导电膜包含作为必要组分的聚合物，聚合物占导电膜的重量比重为50～95％，优选的，聚合物选自热塑性聚合物。为了使导电膜能够导电，有两种可行的形式：(1)聚合物为导电聚合物；(2)除了聚合物之外，导电膜还包含导电填料。The conductive film contains a polymer as an essential component, and the polymer accounts for 50 to 95% by weight of the conductive film. Preferably, the polymer is selected from a thermoplastic polymer. In order to make the conductive film conductive, there are two possible forms: (1) the polymer is a conductive polymer; (2) in addition to the polymer, the conductive film further contains a conductive filler.
导电聚合物选材要求为具有导电能力但电化学惰性，即不会作为电荷转移介质的离子导电。具体的，导电聚合物包括但不仅限于聚乙炔、聚吡咯、聚噻吩、聚苯硫醚、聚苯胺、聚丙烯腈、聚喹啉、聚对苯撑(polyparaphenylene)及其任意混合物。导电聚合物本身就具有导电性，但还可以对导电聚合物进行掺杂或改性以进一步提高其导电能力。从导电性能和电池中的稳定使用考 量，导电聚合物优选聚苯胺、聚吡咯、聚噻吩和聚乙炔。Conductive polymer materials are required to be electrically conductive but electrochemically inert, i.e., not ionically conductive as a charge transfer medium. Specifically, conductive polymers include, but are not limited to, polyacetylene, polypyrrole, polythiophene, polyphenylene sulfide, polyaniline, polyacrylonitrile, polyquinoline, polyparaphenylene, and any mixtures thereof. The conductive polymer itself is electrically conductive, but the conductive polymer can also be doped or modified to further increase its electrical conductivity. From conductive properties and stable use in batteries The conductive polymer is preferably polyaniline, polypyrrole, polythiophene or polyacetylene.
同样的，导电填料的选材要求为表面积小、难于氧化、结晶度高、具有导电性但电化学惰性，即不会作为电荷转移介质的离子导电。Similarly, the selection of conductive fillers requires small surface area, difficulty in oxidation, high crystallinity, electrical conductivity, but electrochemical inertness, ie, ion conduction that does not act as a charge transfer medium.
导电填料的材料包括但不仅限于导电聚合物、碳基材料或金属氧化物。导电填料在导电膜中的质量百分比范围为5～50％。导电填料的平均粒径并没有特别限定，通常范围在100nm～100μm。Materials for the conductive filler include, but are not limited to, conductive polymers, carbon-based materials, or metal oxides. The mass percentage of the conductive filler in the conductive film ranges from 5 to 50%. The average particle diameter of the conductive filler is not particularly limited, and is usually in the range of 100 nm to 100 μm.
当导电膜中包含导电填料时，导电膜中的聚合物优选包含起到结合导电填料作用的非导电聚合物，非导电聚合物增强了导电填料的结合，改善了电池的可靠性。优选的，非导电聚合物为热塑性聚合物。When the conductive film contains a conductive filler, the polymer in the conductive film preferably contains a non-conductive polymer that functions to bond the conductive filler, and the non-conductive polymer enhances the bonding of the conductive filler, improving the reliability of the battery. Preferably, the non-conductive polymer is a thermoplastic polymer.
具体的，热塑性聚合物包括但不仅限于聚烯烃如聚乙烯、聚丙烯，聚丁烯，聚氯乙烯，聚苯乙烯，聚酰胺，聚碳酸酯，聚甲基丙烯酸甲酯，聚甲醛，聚苯醚，聚砜，聚醚砜、丁苯橡胶或聚偏氟乙烯中的一种或多种。其中，优选为聚烯烃、聚酰胺和聚偏氟乙烯。这些聚合物容易通过热而熔化，因此容易与正极集流体复合在一起。此外，这些聚合物具有大电位窗口，从而使正极稳定并为电池输出密度节省重量。Specifically, thermoplastic polymers include, but are not limited to, polyolefins such as polyethylene, polypropylene, polybutene, polyvinyl chloride, polystyrene, polyamide, polycarbonate, polymethyl methacrylate, polyoxymethylene, polyphenylene. One or more of ether, polysulfone, polyethersulfone, styrene butadiene rubber or polyvinylidene fluoride. Among them, preferred are polyolefins, polyamides and polyvinylidene fluoride. These polymers are easily melted by heat and are therefore easily compounded with the cathode current collector. In addition, these polymers have a large potential window to stabilize the positive electrode and save weight for battery output density.
示例的，导电膜可以通过热压复合、抽真空或喷涂的方式结合到正极集流体上。By way of example, the conductive film can be bonded to the positive current collector by hot press lamination, vacuuming or spraying.
选择三Choose three
更加优选的，正极集流体包括载体和包覆在载体上的石墨。More preferably, the cathode current collector comprises a carrier and graphite coated on the carrier.
为了保证正极具有高的能量密度，因此正极集流体的厚度需要有合适的选择。优选的，石墨的厚度范围为0.1-0.2mm；载体的厚度小于1mm，优选的，载体的厚度范围为0.1-0.2mm。In order to ensure a high energy density of the positive electrode, the thickness of the positive electrode current collector needs to be appropriately selected. Preferably, the thickness of the graphite ranges from 0.1 to 0.2 mm; the thickness of the carrier is less than 1 mm, and preferably, the thickness of the carrier ranges from 0.1 to 0.2 mm.
优选的，石墨中碳的含量大于97％，避免石墨中的杂质对电池性能的影响。Preferably, the carbon content of the graphite is greater than 97% to avoid the influence of impurities in the graphite on the performance of the battery.
优选的，石墨的形态为石墨纸(graphite foil)，又称石墨箔。通常，石墨纸是由石墨粉经过一系列加工，压轧成柔韧、轻薄的纸状石墨。优选的，石墨纸的密度大于1.0g/cm3，石墨纸密度越大，其结构越致密，从而保证用在水系电池中石墨纸表面不容易起泡，性能稳定。Preferably, the form of graphite is graphite foil, also known as graphite foil. Usually, graphite paper is processed from a series of graphite powders into a flexible, lightweight paper-like graphite. Preferably, the density of the graphite paper is greater than 1.0 g/cm 3 , and the density of the graphite paper is larger, and the structure is denser, thereby ensuring that the surface of the graphite paper used in the water-based battery is not easily foamed and the performance is stable.
载体本身电化学惰性，根据本领域技术人员公知，电化学惰性即载体不参与任何电化学反应。载体主要起到承载石墨的作用，从而提高石墨的机械性能，石墨主要起到收集和传导电子的作用。The support itself is electrochemically inert and, as is well known to those skilled in the art, is electrochemically inert, i.e., the support does not participate in any electrochemical reaction. The carrier mainly functions to carry graphite, thereby improving the mechanical properties of the graphite, and the graphite mainly functions to collect and conduct electrons.
示例的，载体的材料选自聚对苯二甲酸乙二酯、聚对苯二甲酸丁二酯、 聚乙烯、聚丙烯、聚酰胺、聚氨基甲酸酯、聚丙烯腈中的一种。这些聚合物材料可以稳定的存在于正极集流体中而不参与电化学反应，为电池较高的能量密度输出节省重量。优选的，载体为尼龙网，即聚酰胺。Illustratively, the material of the carrier is selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, One of polyethylene, polypropylene, polyamide, polyurethane, and polyacrylonitrile. These polymeric materials can be stably present in the positive current collector without participating in the electrochemical reaction, saving weight for the higher energy density output of the battery. Preferably, the carrier is a nylon mesh, ie a polyamide.
示例的，石墨纸通过热压复合，滚压或胶粘的方式包覆在载体上。Illustratively, the graphite paper is coated on the carrier by hot pressing, rolling or gluing.
负极根据其结构以及作用的不同，可以为以下三种不同的形式：The negative electrode can be in three different forms depending on its structure and function:
负极仅包括负极集流体，并且负极集流体仅作为电子传导和收集的载体，不参与电化学反应。The negative electrode includes only the negative electrode current collector, and the negative electrode current collector serves only as a carrier for electron conduction and collection, and does not participate in the electrochemical reaction.
示例的，负极集流体为铜箔、不锈钢网、不锈钢箔或石墨箔。By way of example, the anode current collector is a copper foil, a stainless steel mesh, a stainless steel foil or a graphite foil.
负极仅包括负极活性物质，负极活性物质同时作为负极集流体。示例的，第二金属离子为锌离子，负极为锌箔。锌箔可参与负极反应。The negative electrode includes only the negative electrode active material, and the negative electrode active material simultaneously serves as the negative electrode current collector. Illustratively, the second metal ion is zinc ion and the negative electrode is zinc foil. The zinc foil can participate in the negative electrode reaction.
优选的，负极包括负极活性物质和负极集流体，负极活性物质负载在负极集流体上。负极活性物质与第二金属相同，如电解液中第二金属离子为Zn2+，第二金属为金属Zn，那么负极活性物质对应也为金属Zn。更加优选的，负极包括黄铜箔和锌箔，黄铜箔作为负极集流体，锌箔对应负极活性物质，可参与负极反应。Preferably, the negative electrode includes a negative electrode active material and a negative electrode current collector, and the negative electrode active material is supported on the negative electrode current collector. The negative electrode active material is the same as the second metal. For example, if the second metal ion in the electrolyte is Zn 2+ and the second metal is metal Zn, the negative electrode active material is also metal Zn. More preferably, the negative electrode includes a brass foil and a zinc foil, the brass foil serves as a negative electrode current collector, and the zinc foil corresponds to the negative electrode active material and can participate in the negative electrode reaction.
负极活性物质以片状或者粉末状存在。当负极活性物质为片状时，负极活性物质与负极集流体形成复合层。当负极活性物质为粉末时，将第二金属粉末制成浆料，然后将浆料涂覆在负极集流体上制成负极。在具体的实施方式中，制备负极时，除了负极活性物质第二金属粉末之外，根据实际情况，还根据需要添加负极导电剂和负极粘结剂来提升负极的性能。The negative electrode active material exists in the form of a sheet or a powder. When the negative electrode active material is in the form of a sheet, the negative electrode active material forms a composite layer with the negative electrode current collector. When the anode active material is a powder, the second metal powder is slurried, and then the slurry is coated on the anode current collector to form a cathode. In a specific embodiment, when preparing the negative electrode, in addition to the negative electrode active material second metal powder, the negative electrode conductive agent and the negative electrode binder are added as needed to improve the performance of the negative electrode.
电解液包括电解质以及溶剂水；电解质至少能够电离出第一金属离子和第二金属离子；第一金属离子在充放电过程中在正极能够可逆脱出-嵌入；第二金属离子在充电过程中在负极还原沉积为第二金属，第二金属在放电过程中氧化溶解为第二金属离子。The electrolyte includes an electrolyte and a solvent water; the electrolyte is capable of at least ionizing the first metal ion and the second metal ion; the first metal ion can be reversibly extracted-embedded in the positive electrode during charging and discharging; and the second metal ion is in the negative electrode during charging The reduction deposition is a second metal, and the second metal is oxidized and dissolved into a second metal ion during discharge.
第二金属离子选自锰离子、铁离子、铜离子、锌离子、铬离子、镍离子、锡离子或铅离子。The second metal ion is selected from the group consisting of manganese ions, iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin ions or lead ions.
在一优选实施例下，本发明的第一金属离子选自锂离子，同时第二金属离子选自锌离子，即电解液中阳离子为锂离子和锌离子。In a preferred embodiment, the first metal ion of the present invention is selected from the group consisting of lithium ions, while the second metal ion is selected from the group consisting of zinc ions, i.e., the cations in the electrolyte are lithium ions and zinc ions.
电解液中阴离子，可以是任何基本不影响正负极反应、以及电解质在溶剂中的溶解的阴离子。例如可以是硫酸根离子、氯离子、醋酸根离子、甲酸根离子、磷酸根离子、烷基磺酸根离子及其混合等。具体的，烷基磺酸根离子可为甲基磺酸根离子等。 The anion in the electrolyte may be any anion which does not substantially affect the positive and negative electrode reactions and the dissolution of the electrolyte in the solvent. For example, it may be a sulfate ion, a chloride ion, an acetate ion, a formate ion, a phosphate ion, an alkylsulfonate ion, a mixture thereof, or the like. Specifically, the alkylsulfonate ion may be a methanesulfonate ion or the like.
电解液中各离子的浓度，可以根据不同电解质、溶剂、以及电池的应用领域等不同情况而进行改变调配。The concentration of each ion in the electrolyte can be changed according to different conditions of different electrolytes, solvents, and application fields of the battery.
优选的，在电解液中，第一金属离子的浓度为0.1～10mol/L。优选的，在电解液中，第二金属离子的浓度为0.5～15mol/L。优选的，在电解液中，阴离子的浓度为0.5～12mol/L。Preferably, in the electrolytic solution, the concentration of the first metal ion is 0.1 to 10 mol/L. Preferably, the concentration of the second metal ion in the electrolytic solution is 0.5 to 15 mol/L. Preferably, the concentration of the anion in the electrolytic solution is from 0.5 to 12 mol/L.
优选的，电解液的pH值为2-8。Preferably, the pH of the electrolyte is 2-8.
优选在电解液中位于正极与负极之间还设有隔膜。隔膜可以避免其他意外因素造成的正负极相连而造成的短路。Preferably, a separator is further provided between the positive electrode and the negative electrode in the electrolytic solution. The diaphragm can avoid short circuits caused by the connection of positive and negative electrodes caused by other unexpected factors.
隔膜没有特殊要求，只要是允许电解液通过且电子绝缘的隔膜即可。有机系锂离子电池采用的各种隔膜，均可以适用于本发明。隔膜还可以是微孔陶瓷隔板、玻璃纤维AGM或AFG等其他材料。The separator is not particularly required as long as it is a separator that allows the electrolyte to pass through and is electrically insulated. Various separators used in organic lithium ion batteries can be applied to the present invention. The separator may also be a microporous ceramic separator, glass fiber AGM or AFG.
本发明的电池，以多孔石墨烯作为电池的正极导电剂，石墨烯具有均匀的连续的多孔网络结构和很好的亲水性能，能够很好的容纳水系电解液，使水系电解液和活性物质可以充分接触，提高正极材料电子导电和离子导电率，从而提高电池正极循环寿命和倍率性能。这种石墨烯作为导电材料在水系电池中具有很好的应用前景。The battery of the invention adopts porous graphene as the positive electrode conductive agent of the battery, and the graphene has a uniform continuous porous network structure and good hydrophilic property, can well accommodate the aqueous electrolyte, and makes the aqueous electrolyte and the active material. It can be fully contacted to improve the electronic conductivity and ionic conductivity of the positive electrode material, thereby improving the cycle life and rate performance of the battery positive electrode. Such graphene has a good application prospect in water-based batteries as a conductive material.
本发明中所使用的所有专业与科学用语与本领域熟练人员所熟悉的意义相同。此外，任何与所记载内容相似或均等的方法及材料皆可应用于本发明方法中。文中所述的较佳实施方法与材料仅作示范之用。All of the professional and scientific terms used in the present invention have the same meaning as those skilled in the art. In addition, any methods and materials similar or equivalent to those described may be employed in the methods of the invention. The preferred embodiments and materials described herein are for illustrative purposes only.
下面结合实施例，更具体地说明本发明的内容。应当理解，本发明的实施并不局限于下面的实施例，对本发明所做的任何形式上的变通和/或改变都将落入本发明保护范围。在本发明中，若非特指，所有的百分比均为重量单位，所有的设备和原料等均可从市场购得或是本行业常用的。The contents of the present invention will be more specifically described below with reference to the embodiments. It is to be understood that the invention is not limited to the embodiments described below, and that any form of modifications and/or changes made to the invention are intended to fall within the scope of the invention. In the present invention, unless otherwise specified, all percentages are by weight, and all equipment and materials are commercially available or commonly used in the industry.
实施例Example
以下，通过实施例对本发明进行更具体的说明，但本发明不受这些实施例的限制。Hereinafter, the present invention will be more specifically described by the examples, but the present invention is not limited by the examples.
实施例1Example 1
电解液1-1的制备Preparation of electrolyte 1-1
称取一定量的Li2SO4和ZnSO4溶于去离子水中，并使Li2SO4和ZnSO4的浓度分别为1M和2M，进一步向去离子水中添加MgSO4，并使其浓度为0.01M。Weigh a certain amount of Li 2 SO 4 and ZnSO 4 dissolved in deionized water, and make the concentrations of Li 2 SO 4 and ZnSO 4 are 1M and 2M, respectively, and further add MgSO 4 to the deionized water to a concentration of 0.01. M.
电解液1-2的制备Preparation of electrolyte 1-2
称取一定量的Li2SO4和ZnSO4溶于去离子水中，并使Li2SO4和ZnSO4 的浓度分别为1M和2M，进一步向去离子水中添加MgSO4，并使其浓度为0.05M。A certain amount of Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively, and MgSO 4 was further added to deionized water to a concentration of 0.05. M.
电解液1-3的制备Preparation of electrolyte 1-3
称取一定量的Li2SO4和ZnSO4溶于去离子水中，并使Li2SO4和ZnSO4的浓度分别为1M和2M，进一步向去离子水中添加MgSO4，并使其浓度为0.25M。A certain amount of Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively, and MgSO 4 was further added to deionized water to a concentration of 0.25. M.
电解液1-4的制备Preparation of electrolyte 1-4
称取一定量的Li2SO4和ZnSO4溶于去离子水中，并使Li2SO4和ZnSO4的浓度分别为1M和2M，进一步向去离子水中添加MgSO4，并使其浓度为0.5M。A certain amount of Li 2 SO 4 and ZnSO 4 were weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively, and MgSO 4 was further added to deionized water to a concentration of 0.5. M.
对比电解液1的制备Preparation of Comparative Electrolyte 1
称取一定量的Li2SO4和ZnSO4溶于去离子水中，并使Li2SO4和ZnSO4的浓度分别为1M和2M。A certain amount of Li 2 SO 4 and ZnSO 4 was weighed and dissolved in deionized water, and the concentrations of Li 2 SO 4 and ZnSO 4 were 1 M and 2 M, respectively.
Swagelok电池的制备Preparation of Swagelok battery
将正极活性物质锰酸锂LMO、粘结剂羟甲基纤维素CMC、丁苯橡胶SBR、以及导电剂石墨KS15按照质量比84.5:1.5:2:12在水中混合，形成均匀的正极浆料。将正极浆料涂覆在正极集流体上形成活性物质层，随后将其进行压片，制成正极片，活性物质LMO的面密度为250g/m2，面积为1cm2。The positive electrode active material lithium manganate LMO, binder hydroxymethyl cellulose CMC, styrene-butadiene rubber SBR, and conductive agent graphite KS15 were mixed in water at a mass ratio of 84.5:1.5:2:12 to form a uniform positive electrode slurry. The positive electrode slurry was coated on a positive electrode current collector formed active material layer, which is then tableted to prepare a positive electrode sheet, the LMO active material areal density of 250g / m 2, an area of 1cm 2.
电解液采用上述电解液1-1、1-2、1-4，负极采用锌箔，隔膜采用玻璃纤维隔膜AGM，制备Swagelok电池。对应的Swagelok电池，分别记为B1、B2、B4。采用相同正极、负极、隔膜以及对比电解液1制备Swagelok电池，记为S1。The electrolyte was prepared by using the above electrolytes 1-1, 1-2, and 1-4, the negative electrode was made of zinc foil, and the separator was made of glass fiber separator AGM to prepare a Swagelok battery. The corresponding Swagelok batteries are denoted as B1, B2, and B4, respectively. A Swagelok battery was prepared using the same positive electrode, negative electrode, separator, and comparative electrolyte 1, designated S1.
性能测试：Performance Testing:
针对Swagelok电池B1、B2、B4以及对比例S1，首先在室温下充放电循环3次后标定容量，然后将电池静置24小时，分别测量了室温下的开路电压(OCV)和容量保持率，结果如表1所示。For the Swagelok batteries B1, B2, B4 and the comparative example S1, the capacity was first calibrated after charging and discharging three times at room temperature, and then the battery was allowed to stand for 24 hours, and the open circuit voltage (OCV) and the capacity retention ratio at room temperature were measured, respectively. The results are shown in Table 1.
表1 Swagelok蓄电池室温下的开路电压(OCV)和容量保持率。Table 1 Open circuit voltage (OCV) and capacity retention at room temperature for Swagelok batteries.
电解液Electrolyte OCV(V)OCV(V) 容量保持率Capacity retention rate
S1S1 1.961.96 93％93%
B1(0.01M)B1 (0.01M) 1.971.97 93％93%
B2(0.05M)B2 (0.05M) 1.981.98 95％95%
B4(0.5M)B4 (0.5M) 2.012.01 97％97%
如表1中所示，开路电压(OCV)随着添加剂离子Mg离子浓度的增加而 增加。加入0.5M镁离子的B4电池的开路电压在2.01V，比S1电池的开路电压高出约50mV，而放电容量损失仅为3％，低于S1的放电容量损失7％，放电容量损失的降低的幅度达到了57％。加入0.05M的Mg离子的B2电池的OCV提高到1.98V，与S1电池相比，开路电压提高了约20mV。同时，B2的放电容量损失为约5％，而S1的放电容量损失为7％，B2的放电容量损失减小到S1的70％左右。可以理解的是，电池的容量保持率提升了，表明电池的自放电率和正极导电剂碳的损失均有减少。从电池的反应原理看，锂离子的尺寸相对小，能够在充放电的过程中自由的在锰酸锂的晶体结构中移动。而如Na离子、Mg离子、Al离子等添加剂离子的尺寸相对而言较大，不能够嵌入锰酸锂的晶体结构中，因此，电池的比容量不会因为增加了这些添加剂离子而增大，但是，这些添加剂离子能够在电解液中自由移动，会阻碍锂离子的移动通道。因此，锂离子的脱出-嵌入的电池自放电反应速度降低了。另一方面，添加剂离子提升了氧的析出电位，减缓了电池中的其他离子可能与氧反应产生氧化物的副反应的发生。As shown in Table 1, the open circuit voltage (OCV) increases with the additive ion Mg ion concentration. increase. The open circuit voltage of B4 battery with 0.5M magnesium ion is 2.01V, which is about 50mV higher than the open circuit voltage of S1 battery, and the discharge capacity loss is only 3%, which is lower than the discharge capacity loss of 7% and the discharge capacity loss is lower. The magnitude reached 57%. The OCV of a B2 battery with 0.05M Mg ions added was increased to 1.98V, and the open circuit voltage was increased by about 20mV compared to the S1 battery. At the same time, the discharge capacity loss of B2 is about 5%, and the discharge capacity loss of S1 is 7%, and the discharge capacity loss of B2 is reduced to about 70% of S1. It can be understood that the capacity retention rate of the battery is improved, indicating that the self-discharge rate of the battery and the loss of the positive conductive agent carbon are reduced. From the reaction principle of the battery, the size of the lithium ion is relatively small, and it can freely move in the crystal structure of lithium manganate during charge and discharge. However, the size of the additive ions such as Na ions, Mg ions, and Al ions is relatively large, and cannot be embedded in the crystal structure of lithium manganate. Therefore, the specific capacity of the battery does not increase due to the increase of these additive ions. However, these additive ions are free to move in the electrolyte and hinder the movement of lithium ions. Therefore, the lithium ion elution-embedded battery self-discharge reaction rate is lowered. On the other hand, the additive ions increase the oxygen evolution potential and slow down the occurrence of side reactions in which other ions in the battery may react with oxygen to produce oxides.
循环性能测试Cycle performance test
将电池B1、B3、B4在常温下，以3C倍率在1.4V～2.1V电压范围内进行充放电循环测试，测试结果如图1～3所示。The batteries B1, B3, and B4 were subjected to a charge and discharge cycle test at a constant temperature of 3 C at a voltage ranging from 1.4 V to 2.1 V, and the test results are shown in Figs.
充放电倍率高时，具有Mg离子添加剂的电池表现出较好的循环性能。如图1-3所示，高的放电倍率下，需要花费大约50个循环实现稳定放电容量。放电容量稳定后，能够在几百周的循环中保持放电容量的波动不超过5％。而S1中，300个循环周期后的容量保持率仅为80％。因此，添加Mg离子，电池的循环寿命和稳定性获得了显著的提升。预期电池在1000个循环之后仍然能够有95％的循环保持率。对测试电池进行内部拆解，可以看到，800个循环周期内，带有Mg离子添加剂的电池未发现枝晶的现象，而没有Mg离子添加剂的电池在100～300个循环周期左右，发现枝晶现象。When the charge/discharge rate is high, the battery having the Mg ion additive exhibits better cycle performance. As shown in Figures 1-3, at a high discharge rate, it takes about 50 cycles to achieve a stable discharge capacity. After the discharge capacity is stabilized, the fluctuation of the discharge capacity can be maintained within a cycle of several hundred weeks without exceeding 5%. In S1, the capacity retention rate after 300 cycles is only 80%. Therefore, by adding Mg ions, the cycle life and stability of the battery are significantly improved. The battery is expected to still have a 95% cycle retention after 1000 cycles. Internally disassembled the test battery, it can be seen that in the 800 cycle cycle, the battery with the Mg ion additive did not detect dendrite, while the battery without the Mg ion additive was found in the range of 100 to 300 cycles. Crystal phenomenon.
进一步，针对电池B1和S1分别以0.2C和1C的倍率进行充放电循环测试，电压范围为1.4V～2.1V。1C倍率下电池B1和S1在50、100以及150个循环后的容量保持率，结果显示在表2中。Further, the charge and discharge cycle tests were performed for the batteries B1 and S1 at a magnification of 0.2 C and 1 C, respectively, and the voltage range was 1.4 V to 2.1 V. The capacity retention ratios of the batteries B1 and S1 after 50, 100, and 150 cycles at 1 C rate, and the results are shown in Table 2.
与S1相比，B1电池的1C倍率下的比容量略有下降，但在100个循环和150个循环后，B1的容量保持率明显优于S1的容量保持率，可见添加了Mg离子后，显著地提高了电池的循环性能。Compared with S1, the specific capacity at 1C rate of B1 battery decreased slightly, but after 100 cycles and 150 cycles, the capacity retention rate of B1 was significantly better than that of S1. It can be seen that after adding Mg ions, Significantly improved battery cycle performance.
表2Table 2
电解液/容量Electrolyte/capacity 0.2C比容量0.2C specific capacity 1C的比容量Specific capacity of 1C 50个50 100个100 150个150
保持率(％)Retention rate (%) mAh/gmAh/g mAh/gmAh/g 循环cycle 循环cycle 循环cycle
S1S1 115.1115.1 91.191.1 96.6％96.6% 92.6％92.6% 91.3％91.3%
B1B1 117.9117.9 85.185.1 96.8％96.8% 95.4％95.4% 94.7％94.7%
实施例2Example 2
电解液2的制备Preparation of electrolyte 2
称取一定量的Li2SO4和ZnSO4溶于去离子水中，并使Li2SO4和ZnSO4的浓度分别为1M和2M，进一步向去离子水中添加一定量的MnSO4，并使MnSO4的浓度为0.8M。Weigh a certain amount of Li 2 SO 4 and ZnSO 4 dissolved in deionized water, and make the concentrations of Li 2 SO 4 and ZnSO 4 are 1M and 2M, respectively, further add a certain amount of MnSO 4 to deionized water, and make MnSO The concentration of 4 is 0.8M.
电池的制备Battery preparation
采用与电池B1相同的正极、负极、隔膜，并以电解液2为电解液制备电池Swagelok电池，记为B5。A battery Swagelok battery was prepared using the same positive electrode, negative electrode, and separator as the battery B1, and the electrolyte 2 was used as an electrolyte, and it was designated as B5.
性能测试：Performance Testing:
将电池B5在常温下，以0.2C倍率充放电，其中充电截止电压为2.1V，放电截止电压为1.4、1.2、1.0、0.5直到0V。测定得到的电池的充放电曲线。The battery B5 was charged and discharged at a rate of 0.2 C at a normal temperature, wherein the charge cutoff voltage was 2.1 V, and the discharge cutoff voltage was 1.4, 1.2, 1.0, 0.5 up to 0 V. The charge and discharge curves of the obtained battery were measured.
针对实施例2的电池，从图4的放电曲线中可以看出，如果放电到1.4V，放电曲线有两个充放电平台，电池的比容量为110mAh/g。如果放电到0.5V左右，在小于1.4V时出现了一个新的放电平台，电池的比容量约为180mAh/g，可见添加了Mn离子后，电池可以实现深度放电。For the battery of Example 2, it can be seen from the discharge curve of Fig. 4 that if the discharge is 1.4 V, the discharge curve has two charge and discharge platforms, and the specific capacity of the battery is 110 mAh/g. If the discharge reaches about 0.5V, a new discharge platform appears at less than 1.4V. The specific capacity of the battery is about 180mAh/g. It can be seen that after the addition of Mn ions, the battery can achieve deep discharge.
电池B5在常温下以0.2C倍率充放电，测量电池循环性能。放电到0.5V的结果如图5所示。以0.2C倍率放电至0.5V，电池的容量保持在160-180mAh/g之间超过20个循环周期。The battery B5 was charged and discharged at a rate of 0.2 C at a normal temperature, and the battery cycle performance was measured. The result of discharging to 0.5 V is shown in Fig. 5. The battery was discharged to 0.5 V at a rate of 0.2 C, and the capacity of the battery was maintained at 160-180 mAh/g for more than 20 cycles.
将电池S1和B5在常温下以3C倍率充放电，测量电池充放电循环性能，结果分别如图6和7所示。The batteries S1 and B5 were charged and discharged at a normal temperature of 3 C, and the battery charge and discharge cycle performance was measured. The results are shown in Figs. 6 and 7, respectively.
根据图6和7可以知道，在50个循环之后，B5和S1的容量彼此接近。可见Mn离子加入电解液中时，所增加的额外容量会保持约50个循环。高的放电倍率下，加入Mn离子的电池的库伦效率更好，表明在高的放电倍率下的电池副反应减少了，正极活性材料LMO主要被还原为可逆产物。伴随着电解液中Mn离子的添加，固态LMO的反应速度没有电解液中的Mn离子的反应速度块，因此，在高倍率情况下，电解液中的Mn离子优先参与了反应。As can be seen from Figures 6 and 7, after 50 cycles, the capacities of B5 and S1 are close to each other. It can be seen that when Mn ions are added to the electrolyte, the additional capacity added will remain for about 50 cycles. At high discharge rates, the coulombic efficiency of the battery to which Mn ions are added is better, indicating that the side reaction at the high discharge rate is reduced, and the positive active material LMO is mainly reduced to a reversible product. With the addition of Mn ions in the electrolyte, the reaction rate of the solid LMO is not the reaction rate block of the Mn ions in the electrolyte. Therefore, at a high rate, the Mn ions in the electrolyte preferentially participate in the reaction.
实施例3Example 3
实施例3-1Example 3-1
将氧化镁(分析纯，20-30nm)与去离子水混合，并采用超声波搅拌。将混合物在回流装置中煮沸24小时。过滤并干燥后，将所获得的材料磨成细粉。最后将制得的粉末在500℃下煅烧30分钟去除水，获得具有多孔结构的层状 氧化镁。Magnesium oxide (analytically pure, 20-30 nm) was mixed with deionized water and stirred with ultrasonic waves. The mixture was boiled in a reflux apparatus for 24 hours. After filtration and drying, the obtained material was ground to a fine powder. Finally, the obtained powder was calcined at 500 ° C for 30 minutes to remove water to obtain a layered structure having a porous structure. Magnesium oxide.
将上述制备的氧化镁作为催化剂，垂直设置的石英管式炉在氩气氛围下预热到875℃后，将氧化镁催化剂投入反应器中，通入甲烷气体，气体流量为800毫升/分，通入10分钟。随后冷却至室温，取出所得的材料，通过盐酸洗涤刻蚀去除氧化镁，将产物过滤并在80℃下干燥过夜，即制得多孔的石墨烯，记作PG。The magnesium oxide prepared above was used as a catalyst, and the quartz tube furnace which was vertically arranged was preheated to 875 ° C under an argon atmosphere, and then the magnesium oxide catalyst was put into the reactor, and methane gas was introduced thereto, and the gas flow rate was 800 ml/min. Pass for 10 minutes. Subsequently, the mixture was cooled to room temperature, the obtained material was taken out, magnesium oxide was removed by washing with hydrochloric acid, and the product was filtered and dried at 80 ° C overnight to obtain a porous graphene, which was designated as PG.
对比例3-1Comparative example 3-1
对比例3-1中提供的是采用改良的hummers法制备的氧化还原石墨烯。具体的，将50毫升浓度为1mg/ml的石墨烯氧化物悬浮液超声分散1小时，加入0.5g的还原剂，将所得的混合物在60℃下超声处理12h，然后将制得的材料冷冻干燥12h得到氧化还原石墨烯，记作RGO。Provided in Comparative Example 3-1 is redox graphene prepared by the modified hummers method. Specifically, 50 ml of a graphene oxide suspension having a concentration of 1 mg/ml was ultrasonically dispersed for 1 hour, 0.5 g of a reducing agent was added, and the resulting mixture was ultrasonicated at 60 ° C for 12 hours, and then the obtained material was freeze-dried. Redox graphene was obtained for 12 h and was designated as RGO.
对比例3-2Comparative example 3-2
对比例3-2提供的是剥离石墨烯(Exfoliation graphene)。具体的，采用高速流体剪切辅助超临界CO2剥离法，将膨胀石墨进行剥离，即制得剥离石墨烯，记作EG。Comparative Example 3-2 provides exfoliation graphene. Specifically, the high-speed fluid shear-assisted supercritical CO 2 stripping method is used to peel off the expanded graphite to obtain a peeled graphene, which is referred to as EG.
图8中a、c和e分别为材料PG、RGO和EG的扫描电镜(SEM)照片；图8中b、d和f分别为材料PG、RGO和EG的透射电镜(TEM)照片。从图8中看出，实施例3-1中多孔石墨烯具有均匀的多孔网络结构，同时网络结构是连续的。相比之下，对比例3-1中氧化还原石墨烯尺寸不规则，并且出现了一定的聚集。对比例3-2中剥离石墨烯则为典型的平面结构，并且它们的厚度还很厚，很难将其分离成单层或少层。不同于实施例3-1中的多孔石墨烯，氧化还原石墨烯和剥离石墨烯中没有观察到多孔和皱褶结构。In Fig. 8, a, c and e are scanning electron microscope (SEM) photographs of the materials PG, RGO and EG, respectively; in Fig. 8, b, d and f are transmission electron microscope (TEM) photographs of the materials PG, RGO and EG, respectively. As seen from Fig. 8, the porous graphene in Example 3-1 had a uniform porous network structure while the network structure was continuous. In contrast, the redox graphene in Comparative Example 3-1 was irregular in size and showed some aggregation. The exfoliated graphene in Comparative Example 3-2 is a typical planar structure, and their thickness is still very thick, and it is difficult to separate them into a single layer or a few layers. Unlike the porous graphene in Example 3-1, no porous and wrinkled structures were observed in redox graphene and exfoliated graphene.
另外，实施例3-1中多孔石墨烯的比表面积为1500m2/g，平均孔径为4nm，这一数据与图8中多孔石墨烯的TEM结果也是对应的。Further, the porous graphene of Example 3-1 had a specific surface area of 1,500 m 2 /g and an average pore diameter of 4 nm. This data also corresponds to the TEM result of the porous graphene in Fig. 8.
将实施例3-1、对比例3-1和对比例3-2中多孔石墨烯PG、氧化还原石墨烯RGO和剥离石墨烯EG用作正极导电剂。Porous graphene PG, redox graphene RGO, and exfoliated graphene EG in Example 3-1, Comparative Example 3-1, and Comparative Example 3-2 were used as a positive electrode conductive agent.
实施例4Example 4
实施例4-1Example 4-1
将锰酸锂LiMn2O4(粒径约0.2μm，MTI有限公司)、多孔石墨烯PG、粘结剂聚偏氟乙稀(Kynar，HSV900)按照质量比83:10:7在N-甲基吡咯烷酮(NMP Sigma-Aldrich，纯度≥99.5％)中混合，形成均匀的正极浆料。将正极浆 料涂覆在正极集流体石墨箔(Alfa Aesar)上，60℃下真空干燥24h，裁剪成12mm直径的圆片，制得正极，记作C1。Lithium manganate LiMn 2 O 4 (particle size about 0.2 μm, MTI Co., Ltd.), porous graphene PG, binder polyvinylidene fluoride (Kynar, HSV900) at a mass ratio of 83:10:7 at N-A The pyrrolidone (NMP Sigma-Aldrich, purity ≥ 99.5%) was mixed to form a uniform positive electrode slurry. The positive electrode slurry was coated on a positive current collector graphite foil (Alfa Aesar), vacuum dried at 60 ° C for 24 hours, and cut into a 12 mm diameter disk to prepare a positive electrode, which was designated as C1.
对比例4-1Comparative Example 4-1
在对比例4-1中，正极导电剂采用氧化还原石墨烯RGO，正极其余构成和制备方法同实施例4-1，制得正极，记作C2。In Comparative Example 4-1, the positive electrode conductive agent was a redox graphene RGO, and the remaining composition of the positive electrode was prepared in the same manner as in Example 4-1 to obtain a positive electrode, which was designated as C2.
对比例4-2Comparative Example 4-2
在对比例4-2中，正极导电剂采用剥离石墨烯EG，正极其余构成和制备方法同实施例4-1，制得正极，记作C3。In Comparative Example 4-2, the positive electrode conductive agent was exfoliated graphene EG, and the remaining composition of the positive electrode was prepared in the same manner as in Example 4-1 to obtain a positive electrode, which was designated as C3.
图9为C1(2a，b)、C2(2c)和C3(2d)的SEM照片。从图中可以明显看出：C1中锰酸锂和多孔石墨烯均匀混合，颗粒之间紧密接触，多孔石墨烯没有出现聚集。相比之下，在C2和C3中由于RGO和EG难以在正极材料中分散可以看到明显的聚集。Figure 9 is a SEM photograph of C1 (2a, b), C2 (2c), and C3 (2d). It is apparent from the figure that lithium manganate and porous graphene are uniformly mixed in C1, and the particles are in close contact with each other, and the porous graphene does not aggregate. In contrast, significant aggregation can be seen in C2 and C3 due to the difficulty in dispersing RGO and EG in the positive electrode material.
将实施例4-1、对比例4-1和对比例4-2中正极C1、C2和C3分别组装成水系电池。The positive electrodes C1, C2, and C3 in Example 4-1, Comparative Example 4-1, and Comparative Example 4-2 were assembled into an aqueous battery, respectively.
实施例5Example 5
实施例5-1Example 5-1
电池正极为C1。负极采用12mm直径的锌片(Rotometals，厚度0.2mm)。电解液采用含有1mol/L硫酸锌(Alfa Aesar，纯度≥98％)和2mol/L硫酸锂(Sigma Aldrich，纯度≥98％)的水溶液。调节电解液pH值为4。隔膜采用AGM隔膜(NSG公司)。The positive electrode of the battery is C1. The negative electrode was a 12 mm diameter zinc sheet (Rotometals, thickness 0.2 mm). The electrolytic solution used was an aqueous solution containing 1 mol/L zinc sulfate (Alfa Aesar, purity ≥98%) and 2 mol/L lithium sulfate (Sigma Aldrich, purity ≥98%). Adjust the electrolyte pH to 4. The diaphragm was made of AGM diaphragm (NSG Corporation).
将正极、负极以及隔膜组装成电芯，装入壳体内，然后注入电解液，封口，组装成扣式电池，记作LiMn2O4/PG。The positive electrode, the negative electrode, and the separator were assembled into a battery cell, placed in a casing, and then an electrolyte was injected, sealed, and assembled into a button cell, which was designated as LiMn 2 O 4 /PG.
对比例5-1Comparative example 5-1
电池正极为C2，电池其余构成和制作方法同实施例5-1，制备的电池记作LiMn2O4/RGO。The positive electrode of the battery was C2, and the rest of the battery was constructed and fabricated in the same manner as in Example 5-1, and the battery prepared was designated as LiMn 2 O 4 /RGO.
对比例5-2Comparative Example 5-2
电池正极为C3，电池其余构成和制作方法同实施例5-1，制备的电池记作LiMn2O4/EG。The positive electrode of the battery was C3, and the rest of the battery was constructed and fabricated in the same manner as in Example 5-1, and the prepared battery was designated as LiMn 2 O 4 /EG.
将电池LiMn2O4/PG、LiMn2O4/RGO和LiMn2O4/EG在电压范围1.4-2.1V，以不同倍率(1C＝120mA/g)进行充放电循环测试，测试结果如图10所示。从图10中可以看出，在相同的倍率下，LiMn2O4/PG的放电比容量几乎没有出现衰减，随着倍率增加才出现衰减。另外，在相同的倍率下，LiMn2O4/PG的 放电比容量明显高于LiMn2O4/RGO和LiMn2O4/EG。这一结果说明LiMn2O4/PG的倍率性能明显优于LiMn2O4/RGO和LiMn2O4/EG，也进一步证明多孔石墨烯具有优异的导电子和导离子性能，亲水的多孔石墨烯的孔状结构中可以容纳水系电解液，便于电解液与正极活性物质接触，从而提高正极的倍率性能。The batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG were tested in the voltage range of 1.4-2.1V at different rates (1C=120mA/g). The test results are shown in the figure. 10 is shown. As can be seen from Fig. 10, at the same magnification, the discharge specific capacity of LiMn 2 O 4 /PG hardly attenuates, and attenuation occurs as the magnification increases. In addition, at the same rate, the discharge specific capacity of LiMn 2 O 4 /PG is significantly higher than that of LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG. This result indicates that the rate performance of LiMn 2 O 4 /PG is significantly better than that of LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG, which further proves that porous graphene has excellent conductivity and ion-conducting properties, and is hydrophilic and porous. The pore structure of the graphene can accommodate the aqueous electrolyte, which facilitates the contact between the electrolyte and the positive active material, thereby improving the rate performance of the positive electrode.
将电池LiMn2O4/PG、LiMn2O4/RGO和LiMn2O4/EG在电压范围1.4-2.1V，以4C倍率进行充放电循环测试，测试结果如图11所示。从图11中可以看出，电池LiMn2O4/PG具有很好的循环稳定性，电池循环300次后，放电容量依然有72mAh/g，同时库仑效率接近100％。相比之下，电池LiMn2O4/RGO和LiMn2O4/EG的循环稳定性则较差。The batteries LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG were subjected to a charge and discharge cycle test at a voltage range of 1.4-2.1 V at a rate of 4 C. The test results are shown in FIG. As can be seen from Fig. 11, the battery LiMn 2 O 4 /PG has good cycle stability, and after 300 cycles of the battery, the discharge capacity is still 72 mAh/g, and the coulombic efficiency is close to 100%. In contrast, the battery LiMn 2 O 4 /RGO and LiMn 2 O 4 /EG have poor cycle stability.
电池LiMn2O4/PG、LiMn2O4/RGO和LiMn2O4/EG在4C倍率下充放电循环300次后的电化学阻抗谱如图12所示。从图中可以看出：电池LiMn2O4/PG具有较小的电荷转移电阻，这一结果与其具有良好的倍率性能是吻合的。The electrochemical impedance spectrum of the battery LiMn 2 O 4 /PG, LiMn 2 O 4 /RGO, and LiMn 2 O 4 /EG after charging and discharging cycles at 4 C rate for 300 times is shown in FIG. 12 . It can be seen from the figure that the battery LiMn 2 O 4 /PG has a small charge transfer resistance, which is in good agreement with its good rate performance.
实施例5-2Example 5-2
实施例5-2中的正极，LiMn2O4、多孔石墨烯PG、粘结剂聚偏氟乙稀质量比为89.7:3.3:7。In the positive electrode of Example 5-2, the mass ratio of LiMn 2 O 4 , porous graphene PG, and binder polyvinylidene fluoride was 89.7:3.3:7.
正极、电池其余构成和制备方法同实施例5-1。The positive electrode and the remaining composition of the battery were prepared in the same manner as in Example 5-1.
实施例5-3Example 5-3
实施例5-3中的正极，LiMn2O4、多孔石墨烯PG、粘结剂聚偏氟乙稀质量比为91:2:7。In the positive electrode of Example 5-3, the mass ratio of LiMn 2 O 4 , porous graphene PG, and binder polyvinylidene fluoride was 91:2:7.
正极、电池其余构成和制备方法同实施例5-1。The positive electrode and the remaining composition of the battery were prepared in the same manner as in Example 5-1.
对比例5-3Comparative Example 5-3
对比例5-3中的正极，正极导电剂采用石墨KS-6，正极其余构成和制备方法同实施例5-1。In the positive electrode of Comparative Example 5-3, the positive electrode conductive agent was graphite KS-6, and the remaining composition of the positive electrode was prepared in the same manner as in Example 5-1.
对比例5-3中电池其余构成和制备方法同实施例5-1。The remaining composition and preparation method of the battery in Comparative Example 5-3 was the same as in Example 5-1.
对比例5-4Comparative Example 5-4
对比例5-4中的正极，正极导电剂采用乙炔黑，正极其余构成和制备方法同实施例5-1。For the positive electrode in Comparative Example 5-4, the positive electrode conductive agent was acetylene black, and the remaining composition and preparation method of the positive electrode were the same as those in Example 5-1.
对比例5-4中电池其余构成和制备方法同实施例5-1。The remaining composition and preparation method of the battery in Comparative Example 5-4 was the same as in Example 5-1.
将实施例5-2、5-3、对比例5-3和5-4中电池在电压范围1.4-2.1V，以不同倍率(1C、4C、10C和20C)(1C＝120mA/g)进行充放电循环测试，测试结果显示：实施例5-2中电池具有最好的倍率性能，其次是实施例5-3中电池。 具体在1C、4C或10C倍率下，实施例5-2中电池放电容量高出实施例5-3中电池放电容量约5-8mAh/g，高出对比例5-3和5-4中电池放电容量约10-20mAh/g，而在20C倍率下，实施例5-2中电池放电容量高出实施例5-3中电池放电容量约5mAh/g，高出对比例5-3和5-4中电池放电容量约20-40mAh/g。更佳的，实施例5-2中电池倍率性能优于实施例5-1中电池倍率性能。The batteries in Examples 5-2, 5-3, Comparative Examples 5-3 and 5-4 were subjected to voltages ranging from 1.4 to 2.1 V at different magnifications (1C, 4C, 10C and 20C) (1C = 120 mA/g). The charge and discharge cycle test showed that the battery of Example 5-2 had the best rate performance, followed by the battery of Example 5-3. Specifically, in the case of 1C, 4C or 10C, the discharge capacity of the battery in Example 5-2 is higher than that of the battery in Example 5-3 by about 5-8 mAh/g, which is higher than that in the comparative examples 5-3 and 5-4. The discharge capacity was about 10-20 mAh/g, and at 20C, the battery discharge capacity in Example 5-2 was higher than that in Example 5-3, and the discharge capacity was about 5 mAh/g, which was higher than the comparison ratios 5-3 and 5-. The discharge capacity of the battery in 4 is about 20-40 mAh/g. More preferably, the battery rate performance in Example 5-2 is superior to the battery rate performance in Example 5-1.
将实施例5-2、5-3、对比例5-3和5-4中电池在电压范围1.4-2.1V，以4C倍率进行充放电循环测试，测试结果显示：实施例5-2中电池循环300次后放电容量约为100mAh/g，实施例5-3中电池循环300次后放电容量约90mAh/g，对比例5-3和5-4中电池循环300次后放电容量约为65-75mAh/g。实施例5-2中电池显示了优异的循环性能。同样的，实施例5-2中电池循环性能略优于实施例5-1中电池倍率性能。The batteries in Examples 5-2, 5-3, Comparative Examples 5-3 and 5-4 were subjected to a charge and discharge cycle test at a voltage range of 1.4-2.1 V at a rate of 4 C. The test results showed that the battery of Example 5-2 The discharge capacity was about 100 mAh/g after 300 cycles, the discharge capacity was about 90 mAh/g after 300 cycles of the battery in Example 5-3, and the discharge capacity was about 65 after 300 cycles of the battery in Comparative Examples 5-3 and 5-4. -75 mAh/g. The battery of Example 5-2 showed excellent cycle performance. Also, the battery cycle performance in Example 5-2 was slightly better than that in Example 5-1.
还需要说明的是，在可实施且不明显违背本发明的主旨的前提下，在本说明书中作为某一技术方案的构成部分所描述的任一技术特征或技术特征的组合同样也可以适用于其它技术方案；并且，在可实施且不明显违背本发明的主旨的前提下，作为不同技术方案的构成部分所描述的技术特征之间也可以以任意方式进行组合，来构成其它技术方案。本发明也包含在上述情况下通过组合而得到的技术方案，并且这些技术方案相当于记载在本说明书中。It should also be noted that any technical feature or combination of technical features described in the specification as a component of a certain technical solution may also be applied to the embodiments that can be implemented without obscuring the gist of the present invention. Other technical solutions; and, while being able to implement and not clearly deviating from the gist of the present invention, the technical features described as the constituent parts of the different technical solutions may be combined in any manner to constitute other technical solutions. The present invention also encompasses the technical solutions obtained by the combination in the above case, and these technical solutions are equivalent to those described in the present specification.
以上通过具体实施方式和实施例对本发明进行了说明，但本领域技术人员应该理解的是，这些并非意图对本发明的范围进行限定，本发明的范围应由权利要求书确定。The invention has been described above by way of specific embodiments and examples, but it should be understood by those skilled in the art that the scope of the invention is defined by the scope of the invention.
工业实用性Industrial applicability
根据本发明的电解液及电池，可以实现良好的容量保持率，放电电容损失低，并且能够实现深度放电。 According to the electrolyte and the battery of the present invention, a good capacity retention ratio can be achieved, discharge capacitance loss is low, and deep discharge can be realized.

Claims (15)

  1. 一种用于电池的电解液，其特征在于：所述电解液包括An electrolyte for a battery, characterized in that the electrolyte comprises
    充放电过程中在负极能够还原沉积为金属且该金属能可逆氧化溶解的负极金属离子；a negative electrode metal ion capable of reducing and depositing as a metal in the charge and discharge process and capable of reversible oxidation dissolution of the metal;
    参与电池正极反应的正极离子；以及a positive electrode that participates in the positive electrode reaction of the battery;
    添加剂离子，所述添加剂离子选自Na、Mg、Al、NH4 +、Ni、Co、Ce、Fe、Pb、K或Mn离子中的至少一种，并且所述添加剂离子不同于负极金属离子和正极离子。An additive ion selected from at least one of Na, Mg, Al, NH 4 + , Ni, Co, Ce, Fe, Pb, K or Mn ions, and the additive ion is different from the negative electrode metal ion and Positive ion.
  2. 根据权利要求1所述的电解液，其特征在于，添加剂离子在电解液中的浓度为0.001M～8M。The electrolyte according to claim 1, wherein the concentration of the additive ions in the electrolyte is from 0.001 M to 8 M.
  3. 根据权利要求2所述的电解液，其特征在于，添加剂离子Mg离子在电解液中的浓度为0.001M～1M。The electrolytic solution according to claim 2, wherein the concentration of the additive ion Mg ions in the electrolytic solution is 0.001 M to 1 M.
  4. 根据权利要求1所述的电解液，其特征在于，添加剂离子Ce、Fe、Mn、Pb和/或Co离子在电解液中的浓度为0.1M～8M。The electrolytic solution according to claim 1, wherein the concentration of the additive ions Ce, Fe, Mn, Pb and/or Co ions in the electrolytic solution is from 0.1 M to 8 M.
  5. 根据权利要求1所述的电解液，其特征在于，所述负极金属离子为锌离子。The electrolytic solution according to claim 1, wherein the negative electrode metal ion is zinc ion.
  6. 根据权利要求1所述的电解液，其特征在于，所述正极离子选自锂离子、钠离子或者镁离子。The electrolyte according to claim 1, wherein the positive electrode ion is selected from the group consisting of lithium ion, sodium ion or magnesium ion.
  7. 根据权利要求1所述的电解液，其特征在于，所述负极金属离子为锌离子，所述正极离子为溴离子或钒离子。The electrolytic solution according to claim 1, wherein the negative electrode metal ion is a zinc ion, and the positive electrode ion is a bromide ion or a vanadium ion.
  8. 根据权利要求1所述的电解液，其特征在于，所述电解液的pH值为2～8。The electrolyte according to claim 1, wherein the electrolyte has a pH of from 2 to 8.
  9. 根据权利要求1～8中任一项所述的电解液，其特征在于，所述电解液还包括溶剂，所述溶剂为水和/或醇。The electrolyte according to any one of claims 1 to 8, wherein the electrolyte further comprises a solvent, and the solvent is water and/or an alcohol.
  10. 一种电池，其特征在于：所述电池包括：正极、负极、以及如权利要求1～9中任一项所述的电解液。A battery comprising: a positive electrode, a negative electrode, and the electrolytic solution according to any one of claims 1 to 9.
  11. 根据权利要求10所述的电池，其特征在于，所述正极包括正极材料，所述正极材料包括正极活性物质和正极导电剂，所述正极导电剂为石墨烯，所述石墨烯由单层或者多层石墨烯结构单元组成，所述石墨烯具有孔状结构，孔径分布范围为2-10nm。The battery according to claim 10, wherein the positive electrode comprises a positive electrode material, the positive electrode material comprises a positive electrode active material and a positive electrode conductive agent, the positive electrode conductive agent is graphene, and the graphene is composed of a single layer or A multi-layered graphene structural unit composed of the graphene having a pore-like structure with a pore size distribution ranging from 2 to 10 nm.
  12. 根据权利要求10所述的电池，其特征在于，所述石墨烯的平均孔径范围为3-5nm。The battery according to claim 10, wherein said graphene has an average pore diameter ranging from 3-5 nm.
  13. 根据权利要求10所述的电池，其特征在于，所述石墨烯的尺寸范围 为200-1000nm。The battery according to claim 10, wherein said graphene has a size range It is 200-1000 nm.
  14. 根据权利要求10所述的电池，其特征在于，所述石墨烯的比表面积为300-2000m2/g。The battery according to claim 10, wherein said graphene has a specific surface area of from 300 to 2,000 m 2 /g.
  15. 一种电池组，包括若干个电池，电池如权利要求10所述。 A battery pack comprising a plurality of batteries as claimed in claim 10.
PCT/CN2017/080546 2016-04-15 2017-04-14 Electrolyte solution, battery, and battery pack WO2017177960A1 (en)

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