CN110875473A - Positive electrode active material, preparation method thereof and sodium ion battery - Google Patents
Positive electrode active material, preparation method thereof and sodium ion battery Download PDFInfo
- Publication number
- CN110875473A CN110875473A CN201811019663.2A CN201811019663A CN110875473A CN 110875473 A CN110875473 A CN 110875473A CN 201811019663 A CN201811019663 A CN 201811019663A CN 110875473 A CN110875473 A CN 110875473A
- Authority
- CN
- China
- Prior art keywords
- active material
- positive electrode
- electrode active
- positive
- equal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/364—Composites as mixtures
-
- 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
- H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- 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
Abstract
The application discloses a positive active material, a preparation method thereof and a sodium-ion battery, wherein the molecular formula of the positive active material is AaMeb(PO4)cOxX3‑xWherein A is H, Li, Na, K and NH4Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X is one or more of F, Cl and Br, a is more than 0 and less than or equal to 4, b is more than 0 and less than or equal to 2, c is more than or equal to 1 and less than or equal to 3, and X is more than or equal to 0 and less than or equal to 2; and the thermal weight loss rate of the positive active material is less than or equal to 10% when the temperature is raised from 25 ℃ to 700 ℃. By adopting the positive active material provided by the application, the sodium-ion battery has higher initial capacity, first coulombic efficiency and cycle performance.
Description
Technical Field
The application belongs to the technical field of batteries, and particularly relates to a positive active material, a preparation method of the positive active material and a sodium ion battery.
Background
At present, lithium ion secondary batteries occupy the core position of power batteries, and meanwhile, the lithium ion secondary batteries also face great challenges, such as increasing shortage of lithium resources, increasing price of upstream materials, lagging development of recycling technology, and low recycling rate of old batteries, which all make the market demand for more economical and efficient replacement technology higher and higher. The reserve of sodium resources is far more abundant than that of lithium, the distribution is more extensive, and the cost is far lower than that of lithium, so that the sodium ion battery is a new generation electrochemical system with potential to replace the existing energy storage technology, and has received great attention in scientific research and industry in recent years.
The positive electrode active material is one of the key factors that restrict the performance of the sodium ion battery. The electrochemical performance of the sodium ion battery prepared by the positive active material for the sodium ion battery which is widely researched at present is far lower than that of the lithium ion battery which is commercialized, so that the market competitiveness is unavailable.
Disclosure of Invention
In view of the problems in the background art, the present application aims to provide a positive electrode active material, a method for preparing the same, and a sodium ion battery, which are capable of simultaneously achieving a higher initial capacity, a higher initial coulombic efficiency, and a higher cycle performance.
In order to achieve the above object, a first aspect of the present application provides a positive electrode active material having a formula of aaMeb(PO4)cOxX3-xWherein A is H, Li, Na, K and NH4Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X is one or more of F, Cl and Br, a is more than 0 and less than or equal to 4, b is more than 0 and less than or equal to 2, c is more than or equal to 1 and less than or equal to 3, and X is more than or equal to 0 and less than or equal to 2; and the thermal weight loss rate of the positive active material is less than or equal to 10% when the temperature is raised from 25 ℃ to 700 ℃.
A second aspect of the present application provides a method for preparing a positive electrode active material, the method comprising the steps of:
providing a reaction solution, wherein the reaction solution contains an A source, a Me source, a phosphorus source and an X source;
reacting the reaction solution to obtain a precursor of the positive active material;
carrying out heat treatment on the precursor of the positive electrode active material to obtain the positive electrode active material;
wherein the molecular formula of the positive active material is AaMeb(PO4)cOxX3-xWherein A is H, Li, Na, K and NH4Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X is one or more of F, Cl and Br, a is more than 0 and less than or equal to 4, b is more than 0 and less than or equal to 2, c is more than or equal to 1 and less than or equal to 3, and X is more than or equal to 0 and less than or equal to 2; the thermal weight loss rate of the positive active material is less than or equal to 10% when the temperature is raised from 25 ℃ to 700 ℃.
This application third aspect provides a sodium ion battery, and sodium ion battery includes positive pole piece, negative pole piece, barrier film and electrolyte, and positive pole piece includes the anodal mass flow body and sets up the anodal active material layer on the anodal mass flow body, and anodal active material layer includes the anodal active material of this application first aspect.
Compared with the prior art, the method has the following beneficial effects:
the positive active material provided by the application has a specific chemical composition, and the thermal weight loss rate of the positive active material from 25 ℃ to 700 ℃ is less than or equal to 10%, so that the capacity exertion and the cycle performance of the positive active material can be effectively improved, and the sodium-ion battery has higher initial capacity, first coulombic efficiency and cycle performance.
Detailed Description
In order to make the purpose, technical solution and advantageous technical effects of the present invention clearer, the present invention is described in detail with reference to specific embodiments below. It should be understood that the embodiments described in this specification are only for the purpose of explaining the present application and are not intended to limit the present application.
For the sake of brevity, only some numerical ranges are explicitly disclosed herein. However, any lower limit may be combined with any upper limit to form ranges not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and similarly any upper limit may be combined with any other upper limit to form a range not explicitly recited. Also, although not explicitly recited, each point or individual value between endpoints of a range is encompassed within the range. Thus, each point or individual value can form a range not explicitly recited as its own lower or upper limit in combination with any other point or individual value or in combination with other lower or upper limits.
In the description herein, it is to be noted that, unless otherwise specified, "above" and "below" are inclusive, and "one or more" means "a plurality of" is two or more.
The above summary of the present application is not intended to describe each disclosed embodiment or every implementation of the present application. The following description more particularly exemplifies illustrative embodiments. At various points throughout this application, guidance is provided through a list of embodiments that can be used in various combinations. In each instance, the list is merely a representative group and should not be construed as exhaustive.
Positive electrode active material
The positive electrode active material according to the first aspect of the present application is first explained. The molecular formula of the positive active material is AaMeb(PO4)cOxX3-xWherein A is H, Li, Na, K and NH4Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X is one or more of F, Cl and Br, a is more than 0 and less than or equal to 4, b is more than 0 and less than or equal to 2, c is more than or equal to 1 and less than or equal to 3, and X is more than or equal to 0 and less than or equal to 2; and the thermal weight loss rate of the positive active material is less than or equal to 10% when the temperature is raised from 25 ℃ to 700 ℃.
The cathode active material provided by the application has the advantages of small water content, and few surface-adsorbed functional groups and heteroatoms, can reduce the obstruction in the migration process of electrons and sodium ions, and reduces the side reaction of the cathode interface, thereby effectively improving the capacity exertion and the cycle performance of the cathode active material. In addition, the positive active material has higher crystallinity, and the diffusion and transmission channels of electrons and sodium ions are unobstructed, so that the intrinsic conductivity and the ion conductivity of the positive active material can be improved, and the capacity exertion and the cycle performance of the positive active material are further improved.
In addition, the positive active material provided by the application is beneficial to improving the loading capacity of the positive active material in the positive diaphragm and the compaction density of the positive diaphragm, and is beneficial to enabling the positive active material to be uniformly distributed in the positive diaphragm, so that the capacity exertion and the cycle performance of the battery are further improved.
By adopting the positive active material provided by the application, the sodium-ion battery has higher initial capacity, first coulombic efficiency and cycle performance, and particularly, the initial capacity of the sodium-ion battery can basically reach 100% of the theoretical level.
By adopting the anode active material provided by the application, the preparation processes of the anode slurry and the anode diaphragm can be simplified, and the process efficiency is improved.
Further preferably, the thermal weight loss rate of the positive electrode active material when the temperature is increased from 25 ℃ to 700 ℃ is 6% or less. More preferably, the thermal weight loss rate of the positive electrode active material when the temperature is raised from 25 ℃ to 700 ℃ is 3% or less.
The above-mentioned rate of thermal weight loss is a known meaning in the art, and can be measured by an apparatus and a method known in the art. For example, 20mg of the positive active material is weighed by using a thermal analyzer with the model of relaxation-resistant STA449F3, the positive active material is added into a corundum crucible, and the thermal weight loss rate of the positive active material is tested when the temperature is increased from 25 ℃ to 700 ℃ under the inert gas atmosphere, wherein the temperature increase rate can be 5 ℃/min to 10 ℃/min.
Average particle diameter D of positive electrode active material in the present applicationv50 is preferably 0.2 to 20 μm, more preferably 1 to 15 μm. The positive active material with the particle size distribution is beneficial to improving the capacity exertion, the rate capability and the cycle performance of the sodium-ion battery. If the average particle diameter D isvIf 50 is too small, the preparation of the positive electrode slurry becomes difficult, and the compacted density and porosity of the positive electrode plate are low, so that the electrolyte consumption of the sodium ion battery is high, and the energy density is low. Average particle diameter DvAnd if the content of the electrolyte is less than 50%, side reaction is easy to occur between the positive active material and the electrolyte, the polarization of the positive electrode is increased, the exertion of the material capacity is influenced, and undesirable agglomeration is easy to occur between positive active material particles, so that the rate capability and the cycle performance of the sodium-ion battery are reduced. If the average particle diameter D isvThe size of the particles is too large at 50,the path of ion diffusion is extended, resulting in a decrease in the rate performance of the battery.
Average particle diameter D of positive electrode active materialv50 is understood to mean those known in the art and can be determined by instruments and methods known in the art, for example by means of a laser particle size analyzer of the Mastersizer type 3000.
The BET specific surface area of the positive electrode active material in the present application is preferably 0.05m2/g～20m2(ii)/g, more preferably 1m2/g～15m2(ii) in terms of/g. The positive active material with the BET specific surface area is beneficial to improving the capacity exertion, rate capability and cycle performance of the sodium ion battery. If the BET specific surface area is too large, the contact area of the positive active material particles and the electrolyte is too large, side reactions are generated in the battery in the charging and discharging process, side reaction products are easily enriched on the surface of the material and undergo further oxidation reaction, and further generated products cover the surface of the material, so that the polarization of the positive electrode is increased, part of the positive active material loses activity, the capacity loss is caused, the capacity attenuation of the battery is quicker, and the cycle performance is quickly reduced. When the BET specific surface area is too large, particles of the positive active material are easily agglomerated during preparation of the positive slurry, and the dispersibility of the slurry is poor, so that the positive active material in the positive electrode plate is unevenly distributed and is unevenly contacted with the conductive agent, and the rate performance of the battery is poor. On the other hand, if the BET specific surface area is too small, the area of contact with the electrolyte is small, resulting in an increase in electron transfer resistance, which is manifested by a large internal resistance of the battery, and a significant decrease in cycle performance of the battery.
The BET specific surface area of the positive electrode active material is a value known in the art and can be measured by an apparatus and a method known in the art, for example, by a nitrogen adsorption specific surface area analysis test, which may be performed by a Tri Star type ii specific surface area and pore analyzer from Micromeritics, and calculated by a BET (brunauer emmettteller) method.
The tap density of the positive electrode active material in the present application is preferably 0.4g/cm3～1.8g/cm3More preferablyIs 0.7g/cm3～1.7g/cm3。
The tap density of the positive electrode active material can be conveniently determined using instruments and methods known in the art, for example, using a tap density meter, such as a FZS4-4B tap density meter.
The compacted density of the positive electrode active material at a pressure of 8 tons in the present application is preferably 1.5g/cm3～3.5g/cm3More preferably 2.0g/cm3～3.5g/cm3。
The compacted density of the positive electrode active material can be conveniently determined using instruments and methods known in the art, for example, using an electronic pressure tester, such as an electronic pressure tester model UTM 7305.
Preferably, the positive electrode active material in the present application has tetragonal symmetry, space group P42And/mnm, and contains a characteristic peak of a (211) crystal plane and a characteristic peak of a (301) crystal plane under X-ray diffraction. Meanwhile, the positive active material with the two characteristic peaks has higher crystallinity, better intrinsic conductivity and ion conductivity, and improved surface smoothness, fewer surface heteroatoms and functional groups, and is beneficial to further reducing the thermal weight loss rate of the positive active material and improving the electrochemical performance of the positive active material. The adoption of the positive active material is beneficial to better improving the initial capacity, the first coulombic efficiency and the cycle performance of the sodium-ion battery.
More preferably, the positive electrode active material herein further includes a characteristic peak of a (420) crystal plane under X-ray diffraction, and the half-width is 0.2 ° to 0.5 °.
The diffraction angle 2 θ of the characteristic peak of the (211) plane is, for example, 23.45 ° to 23.85 °. The diffraction angle 2 θ of the characteristic peak of the (301) plane is, for example, 30.60 ° to 31.15 °. The diffraction angle 2 θ of the characteristic peak of the (420) plane is, for example, 44.65 ° to 45.15 °.
The characteristic X-ray diffraction peaks can be determined by means of an X-ray powder diffractometer, for example, using a Brucker model D8A _ A25X-ray diffractometer, with CuKαThe radiation is radiation source, and the wavelength of the radiation
The angle range of the scanning 2 theta is 10-90 DEG, and the scanning speed is 4 DEG/min.
The pH of the positive electrode active material is preferably 3-9. The pH value of the positive active material is too high or too low, so that a gel phenomenon is generated during the preparation of the positive slurry, and the difficulty of the preparation process of the positive pole piece is increased; when the pH is too high or too low, the intrinsic bonding and structure of the material can be changed by the functional group on the surface of the positive active material, so that the exertion of the electrochemical performance of the positive active material is influenced.
In the present application, the powder resistivity of the positive electrode active material under a pressure of 20MPa is preferably 1 Ω · cm to 70000 Ω · cm, and more preferably 20 Ω · cm to 4000 Ω · cm. The positive active material has high intrinsic electronic conductivity, less sodium impurities and other impurities on the surface of the positive active material, and small interface resistance, and can greatly reduce the overall impedance of the battery, thereby improving the capacity exertion, rate capability and cycle performance of the battery.
The powder resistivity of the positive electrode active material under a pressure of 20MPa can be measured by a known powder resistivity test method. As an example, the powder resistivity of the positive active material under a pressure of 20MPa was tested using a four-probe method, which includes: adding the anode active material powder into a sample table, applying a pressure of 20MPa to the powder through a press, and reading the powder resistivity of the anode active material under the pressure of 20MPa through a resistivity meter after the pressure is stable.
Preferably, at least a part of the surface of the positive active material is provided with a carbon coating layer, which is beneficial to further improving the electronic conductivity of the positive active material and reducing the interface resistance, thereby being beneficial to improving the rate capability of the sodium-ion battery.
Further, the weight percentage of the carbon coating layer in the coated positive active material is preferably 0.1 wt% to 15 wt%.
As an example, the carbon coating layer may be one or more of a thermal decomposition product of an organic carbon source, superconducting carbon, acetylene black, carbon nanotube, carbon dot, graphene, ketjen black, and carbon nanofiber. Wherein the organic carbon source can be one or more of glucose, fructose, sucrose, maltose, starch, cellulose, polypyrrole, polyaniline, polythiophene, polyethylenedioxythiophene, polystyrene sulfonate and polyphenylene sulfide.
Method for preparing positive electrode active material
A second aspect of the present application provides a method of preparing a positive electrode active material. According to the production method of the present application, the positive electrode active material of the first aspect of the present application can be obtained.
The preparation method of the positive active material provided by the application comprises the following steps: a step of providing a reaction solution; a reaction step; and a heat treatment step.
As a specific example, the preparation method comprises the following steps:
step S10 of providing a reaction solution: dissolving the A source, the Me source, the phosphorus source and the X source in a solvent according to a stoichiometric ratio to prepare a reaction solution.
And a reaction step S20, transferring the reaction solution into a reaction kettle, reacting at a preset temperature, separating and collecting the obtained precipitation product to obtain the precursor of the positive active material.
And a heat treatment step S30, performing heat treatment on the positive electrode active material precursor to obtain the positive electrode active material.
At step S10, the A source may be a solution containing H, Li, Na, K, NH, as some examples4One or more of carbonate, nitrate, acetate, oxalate, hydroxide and halide; the Me source can be one or more of an inorganic substance containing Me and an organic substance containing Me, for example, when Me is V, the vanadium source can be one or more of vanadium trioxide, vanadium pentoxide, sodium metavanadate, ammonium metavanadate, vanadium trichloride, vanadyl sulfate, vanadyl oxalate, vanadium acetylacetonate and vanadyl acetylacetonate, and for example, when Me is Mn, the manganese source can be one or more of manganese acetate, manganese nitrate, manganese chloride and manganese sulfate; the phosphorus source can be one or more of ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate and phosphoric acid; the X source can be ammonium fluoride or lithium fluorideOne or more of sodium fluoride, potassium fluoride, hydrogen fluoride, ammonium chloride, lithium chloride, sodium chloride, potassium chloride, hydrogen chloride, ammonium bromide, lithium bromide, sodium bromide, potassium bromide, and hydrogen bromide; the solvent may be one or more of deionized water, methanol, ethanol, acetone, isopropanol, n-hexanol, dimethylformamide, ethylene glycol, and diethylene glycol.
It is understood that, in step S10, two or more than three of the a source, the Me source, the phosphorus source, and the X source may be a common source substance, or the a source, the Me source, the phosphorus source, and the X source may be different source substances.
In step S10, the concentration of Me element in the reaction solution is preferably 0.01mol/L to 1.4 mol/L.
When the high-valence Me source is used, a reducing agent (such as oxalic acid) is required to be reduced to a lower valence state, and the molar ratio of the reducing agent to the Me element in the reaction solution is preferably 1: 1-10: 1, and preferably 2: 1-5: 1.
The pH of the reaction solution generally affects the specific surface area, particle size and crystal structure of the reaction product, and optionally includes, in step S10: the pH of the reaction solution is adjusted to be controlled within a predetermined range.
Preferably, the pH of the reaction solution is controlled to be 3 to 9, such as 6 to 8.
The pH of the reaction solution is adjusted by a pH adjuster as necessary. As an example, the pH adjuster may be one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, ammonium bicarbonate, ammonium carbonate, urea, phosphoric acid, oxalic acid, citric acid, and hexamethylenetetramine (commonly known as urotropin). The pH regulator may be added directly to the reaction solution or may be added to the reaction solution in the form of a solution.
In step S20, the reaction temperature is preferably 60 ℃ to 200 ℃, more preferably 90 ℃ to 180 ℃; the reaction time is preferably 5 to 72 hours, more preferably 10 to 30 hours.
Preferably, step S20 further includes: the precipitated product is washed several times with an appropriate amount of solvent. The washing solvent is, for example, water.
Preferably, step S20 further includes: the precipitated product is subjected to a drying treatment at a predetermined temperature.
The drying treatment is performed in a vacuum environment, the drying temperature is preferably 80 ℃ to 140 ℃, and the drying time is preferably 2 hours to 48 hours.
In some embodiments, step S20 may further include: and crushing the dried precipitate.
The precipitation product after drying treatment is crushed to break physical agglomeration among particles caused in the drying process, and then heat treatment is carried out, so that the particles can be prevented from further agglomerating in the heat treatment process to cause agglomeration, and the thermal weight loss rate of the positive active material can be more effectively reduced.
The above-mentioned crushing treatment may be carried out by methods and apparatuses known in the art, for example, using a mechanical crusher.
Preferably, in step S30, the heat treatment temperature is 400 ℃ to 700 ℃ and the heat treatment time is 1 hour to 12 hours.
Further preferably, at step S30, the heat treatment is performed under an inert gas atmosphere, such as an argon atmosphere.
In some preferred embodiments, step S30 includes: and heating the precursor of the positive active material from room temperature to 400-700 ℃ under the atmosphere of inert gas, and carrying out heat treatment on the precursor of the positive active material for 1-12 hours to obtain the positive active material.
The temperature rise rate from room temperature to 400-700 deg.C is, for example, 2-8 deg.C/min, such as 5 deg.C/min; the cooling rate after the heat treatment of the precursor of the positive electrode active material for 1 to 12 hours is, for example, 2 to 8 ℃/min, for example, 5 ℃/min.
In some embodiments, step S30 may further include: and crushing the heat-treated product.
In the heat treatment process, the particles can be agglomerated and grow up, and the heat-treated product can be crushed according to requirements, so that the particle size of the particles is crushed to the micron level, and the positive electrode active material is obtained and has the particle size distribution and the BET specific surface area.
As an example, the crushing treatment of the heat-treated product may be performed by a combination of roll crushing and mechanical crushing, for example, using a ceramic roll crusher and a mechanical crusher, and the heat-treated product is firstly subjected to roll crushing using the ceramic roll crusher, and then the particles are mechanically crushed using the mechanical crusher to crush the particle size to the micrometer level, so as to obtain the positive electrode active material having the particle size distribution and BET specific surface area described above.
Compared with the preparation method, the preparation method of the positive active material with the carbon coating layer on the surface comprises the following steps: a carbon source is also added in step S10. The carbon source is, for example, one or more of an organic carbon source, superconducting carbon, acetylene black, carbon nanotubes, carbon dots, graphene, ketjen black, and carbon nanofibers. The organic carbon source may be one or more of glucose, fructose, sucrose, maltose, starch, cellulose, polypyrrole, polyaniline, polythiophene, polyethylenedioxythiophene, polystyrene sulfonate, and polyphenylene sulfide.
In the positive active material preparation process of this application, through the kind and the concentration of source material, the pH of reaction solution, the kind of pH regulator, reaction temperature and time, drying temperature and time, crushing degree and heat treatment temperature and time etc. carry out comprehensive control, can make positive active material have this application the characteristic, increase substantially positive active material's electrochemical performance, finally make sodium ion battery have higher comprehensive electrochemical performance, sodium ion battery can compromise higher initial capacity, first coulomb efficiency and cyclicity simultaneously.
Positive pole piece
A second aspect of the present application provides a positive electrode sheet, including a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.
The positive electrode current collector may be made of metal foil, carbon-coated metal foil, or porous metal plate, and preferably made of aluminum foil.
The positive electrode active material layer includes the positive electrode active material of the first aspect of the present application.
As an example, the positive electrode active material is Na3V2(PO4)2O2F、Na3V1.95Mn0.05(PO4)2F3、Na3V1.95Mn0.05(PO4)2O2F、Na3V2(PO4)2F3And Na2.95Li0.05V2(PO4)2O2And F is one or more.
The positive active material layer further includes a binder and a conductive agent. The application does not limit the types of the conductive agent and the binder, and can select the conductive agent and the binder according to actual requirements.
As an example, the binder may be one or more of an aqueous binder and an oily binder. The aqueous binder is, for example, one or more of styrene-butadiene rubber (SBR), aqueous-based acrylic resin (water-based acrylic resin), and carboxymethyl cellulose (CMC). The oily binder is, for example, one or more of polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), and polyvinyl alcohol (PVA).
As an example, the conductive agent may be one or more of graphite, superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
The positive electrode sheet can be prepared according to a conventional method in the field. Generally, a positive electrode active material, an optional conductive agent and a binder are dispersed in a solvent (such as N-methylpyrrolidone, abbreviated as NMP) to form uniform positive electrode slurry, the positive electrode slurry is coated on a positive electrode current collector, and the positive electrode sheet is obtained after the processes of drying, cold pressing and the like.
The positive pole piece of the application adopts the positive active material of the application, so that the electrochemical performance is obviously improved.
Sodium ion battery
A third aspect of the present application provides a sodium-ion battery comprising the positive electrode sheet of the second aspect of the present application.
The sodium ion battery also comprises a negative pole piece, a separation film and electrolyte.
The negative electrode plate may be a metal sodium plate, and may also include a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector.
The negative electrode current collector may be made of metal foil, carbon-coated metal foil, porous metal plate, or the like, and is preferably made of copper foil.
The negative electrode active material layer includes a negative electrode active material and optionally a conductive agent, a binder, and a thickener. The negative active material may be one or more of natural graphite, artificial graphite, mesophase micro carbon spheres (MCMB), hard carbon, and soft carbon, the conductive agent may be one or more of graphite, superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, the binder may be one or more of Styrene Butadiene Rubber (SBR), water-based acrylic resin (water-based acrylic resin), carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), and polyvinyl alcohol (PVA), and the thickener may be carboxymethyl cellulose (CMC). However, the present application is not limited to these materials, and other materials that can be used as a negative electrode active material, a conductive agent, a binder, and a thickener for a sodium ion battery may also be used.
The above negative electrode sheet may be prepared according to a conventional method in the art. Generally, a negative electrode active material, an optional conductive agent, a binder and a thickening agent are dispersed in a solvent, wherein the solvent can be deionized water or NMP, so as to form uniform negative electrode slurry, the negative electrode slurry is coated on a negative electrode current collector, and the negative electrode pole piece is obtained after the working procedures of drying, cold pressing and the like.
The separator is not particularly limited, and any known separator having a porous structure and electrochemical and chemical stability may be used, and may be, for example, a single-layer or multi-layer film of one or more of glass fiber, nonwoven fabric, Polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF).
The electrolyte comprises organic solvent and electricityThe electrolyte sodium salt is not limited by the application, and can be selected according to actual requirements. As an example, the organic solvent may be one or more of Ethylene Carbonate (EC), Propylene Carbonate (PC), Ethyl Methyl Carbonate (EMC), and diethyl carbonate (DEC). The sodium salt of the electrolyte may be NaPF6、NaClO4、NaBCl4、NaSO3CF3And Na (CH)3)C6H4SO3One or more of (a).
Stacking the positive pole piece, the isolating film and the negative pole piece in sequence, so that the isolating film is positioned between the positive pole piece and the negative pole piece to play an isolating role, and obtaining the battery cell, or obtaining the battery cell after winding; and (4) placing the battery core in a packaging shell, injecting electrolyte and sealing to obtain the sodium ion battery.
The sodium ion battery adopts the positive pole piece, so that the sodium ion battery has excellent comprehensive electrochemical performance, and has excellent initial capacity, first coulombic efficiency and cycle performance.
Examples
The present disclosure is more particularly described in the following examples that are intended as illustrative only, since various modifications and changes within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are on a weight basis, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and the equipment used in the examples is commercially available.
Example 1
Preparation of positive electrode active material
Step S10, mixing V2O5And an appropriate amount of oxalic acid in deionized water, and then adding NH according to a stoichiometric ratio4H2PO4And NaF to obtain a mixed solution, wherein V2O5The concentration of (A) is 0.4 mol/L;
with Na2CO3The pH of the mixed solution was adjusted to 7 with an aqueous solution to obtain a reaction solution.
And step S20, transferring the reaction solution into a reaction kettle for full reaction at the reaction temperature of 70 ℃ for 24 hours, separating and collecting the obtained precipitation product, washing the precipitation product for a plurality of times by using a proper amount of solvent, drying the precipitation product in a vacuum drying oven at the drying temperature of 120 ℃ for 12 hours, and crushing the precipitation product to ensure that the particle size of the particles is less than or equal to 20 microns to obtain the precursor of the positive active material.
Step S30, carrying out heat treatment on the precursor of the positive active material in a nitrogen atmosphere, wherein the temperature is increased to 550 ℃ at the temperature increase rate of 5 ℃/min, carrying out heat treatment for 4 hours, and then the temperature is decreased to room temperature at the temperature decrease rate of 5 ℃/min, so as to obtain the positive active material Na3V2(PO4)2O2F。
Preparation of button cell
1) Preparation of positive pole piece
Fully stirring and mixing the positive electrode active material prepared in the embodiment, conductive carbon black Super P and a binder polyvinylidene fluoride (PVDF) in a proper amount of N-methylpyrrolidone (NMP) solvent according to the weight ratio of 7:2:1 to form uniform positive electrode slurry; and coating the positive electrode slurry on an aluminum foil of a positive electrode current collector, drying and punching into a circular sheet with the diameter of 14 mm.
2) Preparation of negative pole piece
The metallic sodium sheet was punched into a circular piece with a diameter of 14 mm.
3) The isolating membrane adopts a glass fiber film.
4) Preparation of the electrolyte
Uniformly mixing Ethylene Carbonate (EC) and Propylene Carbonate (PC) with equal volumes to obtain an organic solvent, and then adding 1mol/L sodium perchlorate NaClO4Uniformly dissolved in the organic solvent.
5) Preparation of button cell
And (3) stacking the positive pole piece, the isolating membrane and the negative pole piece in sequence, wherein the isolating membrane is positioned between the positive pole piece and the negative pole piece to play an isolating role to obtain a battery cell, and injecting the electrolyte into the battery cell to finish the preparation of the button cell.
Examples 2 to 19 and comparative examples 1 to 6
Unlike example 1, process parameters during the preparation of the positive electrode active material were adjusted. Specific parameters are detailed in table 1 below.
Test section
1. Positive electrode active material test
(1) Thermogravimetric testing of rate of weight loss
Using a thermal analyzer with the model of relaxation-resistant STA449F3, weighing 20mg of the positive active material, adding into a corundum crucible, and testing the thermal weight loss rate of the positive active material when the temperature rises from 25 ℃ to 700 ℃ at the temperature rise rate of 10 ℃/min under the nitrogen atmosphere.
(2) pH measurement
Dispersing a predetermined amount of positive active material powder into a proper amount of deionized water, enabling the weight ratio of the positive active material to the deionized water to be 1:9, fully stirring for a certain time, standing, taking supernatant, and testing the pH at a constant temperature of 25 ℃ by using a thunder magnetic PHS-3C type pH meter and an E-201-C type glass electrode.
2. Battery performance testing
At 25 ℃, the batteries of the above examples and comparative examples were subjected to constant current charging at 0.1C rate until the voltage was 4.3V, the charging capacity at this time was recorded as the first charge capacity of the sodium ion battery, and then left to stand for 5min, and then subjected to constant current discharging at 0.1C rate until the voltage was 2.0V, and left to stand for 5min, which is a charge-discharge cycle, and the discharge capacity at this time was recorded as the first discharge capacity of the sodium ion battery, which is the initial capacity of the sodium ion battery. And (4) carrying out 100-circle charge-discharge cycle test on the sodium-ion battery according to the method, and recording the discharge capacity of the 100 th circle.
The first-turn coulombic efficiency (%) of the sodium-ion battery is equal to the first-turn discharge capacity/the first-turn charge capacity × 100%.
The capacity retention (%) of the sodium-ion battery after 100 cycles at 25 ℃ was equal to the discharge capacity/first-cycle discharge capacity × 100% at 100 th cycle.
The test results of examples 1 to 19 and comparative examples 1 to 6 are shown in Table 1 below.
TABLE 1
Note: the "/" in comparative examples 1 to 3 indicates that there is no heat treatment step in the preparation of the positive electrode active material.
Comparative example 4 and comparative example 1, comparative example 5 and comparative example 2, and comparative example 6 and comparative example 3, it can be seen that the heat treatment step is added in the preparation of the positive active material, the rate of thermal weight loss of the positive active material when the temperature rises from 25 ℃ to 700 ℃ is reduced, and the initial capacity, the first coulomb efficiency and the capacity retention rate after 100 cycles of circulation of the sodium ion battery are all improved, so that the heat treatment step is added in the preparation of the positive active material, the rate of thermal weight loss of the positive active material is reduced, and the initial capacity, the first coulomb efficiency and the cycle performance of the sodium ion battery can be improved.
Comparing and analyzing examples 1 to 10 and comparative example 4, example 18 and comparative example 5, and example 19 and comparative example 6, it can be seen that when the thermal weight loss rate of the positive active material is not more than 10% when the temperature is raised from 25 ℃ to 700 ℃, the initial capacity, the first coulombic efficiency and the cycle performance of the sodium ion battery are further improved, and the initial capacity of the sodium ion battery is improved from below 104mAh/g to above 110mAh/g, even to above 120 mAh/g; the coulomb efficiency of the first circle of the sodium ion battery is improved from below 85% to above 90%; the capacity retention rate of the sodium-ion battery after 100 cycles is improved from below 62% to above 85%, even to above 90%; therefore, the initial capacity, the first coulombic efficiency and the cycle performance of the sodium-ion battery are obviously improved by adopting the positive active material with the thermal weight loss rate of less than or equal to 10% when the temperature is increased from 25 ℃ to 700 ℃.
It can be known from comparative analysis examples 11 to 17 that the initial capacity, the first coulomb efficiency and the capacity retention rate after 100 cycles of the sodium ion battery can be improved by optimizing the particle size distribution of the positive electrode active material, so that the sodium ion battery has higher initial capacity, first coulomb efficiency and cycle performance.
As can be seen from examples 1 to 19, the positive active material provided by the present application allows a sodium ion battery to have a high initial capacity, a high first coulombic efficiency, and a high cycle performance at the same time.
While the invention has been described with reference to specific embodiments, the scope of the invention is not limited thereto, and those skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (12)
1. A positive electrode active material, characterized in that the molecular formula of the positive electrode active material is AaMeb(PO4)cOxX3-xWherein A is H, Li, Na, K and NH4Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X is one or more of F, Cl and Br, a is more than 0 and less than or equal to 4, b is more than 0 and less than or equal to 2, c is more than or equal to 1 and less than or equal to 3, and X is more than or equal to 0 and less than or equal to 2;
the thermal weight loss rate of the positive active material is less than or equal to 10% when the temperature is raised from 25 ℃ to 700 ℃.
2. The positive electrode active material according to claim 1, wherein the thermal weight loss rate of the positive electrode active material when the temperature rises from 25 ℃ to 700 ℃ is 6% or less, preferably 3% or less.
3. The positive electrode active material according to claim 1, wherein the average particle diameter D of the positive electrode active materialv50 is 0.2 to 20 μm, preferably 1 to 15 μm.
4. The positive electrode active material according to any one of claims 1 to 3, wherein the crystal structure of the positive electrode active material has fourSquare symmetry, space group P42A characteristic peak of a (211) crystal plane and a characteristic peak of a (301) crystal plane under X-ray diffraction;
preferably, the crystal structure of the positive electrode active material further includes a characteristic peak of a (420) crystal plane under X-ray diffraction, and a half-width is 0.2 ° to 0.5 °.
5. The positive electrode active material according to claim 1, wherein the positive electrode active material has a pH of 3 to 9.
6. The positive electrode active material according to claim 1, wherein the tap density of the positive electrode active material is 0.4g/cm3～1.8g/cm3Preferably 0.7g/cm3～1.7g/cm3(ii) a And/or the presence of a gas in the gas,
the positive electrode active material has a compacted density of 1.5g/cm at a pressure of 8 tons3～3.5g/cm3Preferably 2.0g/cm3～3.5g/cm3。
7. The positive electrode active material according to claim 1, wherein the BET specific surface area of the positive electrode active material is 0.05m2/g～20m2A/g, preferably 1m2/g～15m2/g。
8. The positive electrode active material according to any one of claims 1 to 7, wherein at least a part of the surface of the positive electrode active material has a carbon coating layer;
the carbon coating layer accounts for 0.1-15 wt% of the coated positive active material.
9. The positive electrode active material according to any one of claims 1 to 8, wherein the positive electrode active material has a powder resistivity of 1 Ω -cm to 70000 Ω -cm, preferably 20 Ω -cm to 4000 Ω -cm, under a pressure of 20 MPa.
10. A method for producing a positive electrode active material according to any one of claims 1 to 9, comprising the steps of:
providing a reaction solution, wherein the reaction solution contains an A source, a Me source, a phosphorus source and an X source;
reacting the reaction solution to obtain a precursor of the positive active material;
and carrying out heat treatment on the precursor of the positive electrode active material to obtain the positive electrode active material.
11. The method according to claim 10, wherein the heat treatment is performed at a temperature of 400 to 700 ℃ for 1 to 12 hours.
12. A sodium ion battery, comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the positive electrode plate comprises a positive current collector and a positive active material layer disposed on the positive current collector, and the positive active material layer comprises the positive active material according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811019663.2A CN110875473B (en) | 2018-09-03 | 2018-09-03 | Positive electrode active material, preparation method thereof and sodium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811019663.2A CN110875473B (en) | 2018-09-03 | 2018-09-03 | Positive electrode active material, preparation method thereof and sodium ion battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110875473A true CN110875473A (en) | 2020-03-10 |
| CN110875473B CN110875473B (en) | 2021-06-15 |
Family
ID=69716682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811019663.2A Active CN110875473B (en) | 2018-09-03 | 2018-09-03 | Positive electrode active material, preparation method thereof and sodium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110875473B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2748159C1 (en) * | 2020-12-11 | 2021-05-20 | Автономная некоммерческая образовательная организация высшего образования "Сколковский институт науки и технологий" (Сколковский институт науки и технологий) | Electrode material for sodium-ion batteries, method of its production, electrode and battery based on the electrode material |
| CN113437276A (en) * | 2021-06-26 | 2021-09-24 | 宁德时代新能源科技股份有限公司 | Positive electrode active material, electrochemical device, and electronic device |
| CN113614941A (en) * | 2020-10-19 | 2021-11-05 | 宁德新能源科技有限公司 | Electrochemical device and electronic device comprising same |
| CN113745507A (en) * | 2021-09-02 | 2021-12-03 | 东北师范大学 | Vanadium-oxygen-sodium chlorophosphate cathode material, preparation method and sodium ion battery |
| CN114023921A (en) * | 2021-11-01 | 2022-02-08 | 惠州亿纬锂能股份有限公司 | Positive pole piece of sodium-ion battery and preparation method and application thereof |
| WO2022177246A1 (en) * | 2021-02-19 | 2022-08-25 | 전남대학교산학협력단 | Carbon-coated nmtvp nanocomposite positive electrode material, method for manufacturing same, and positive electrode and sodium ion battery comprising same |
| WO2023093180A1 (en) * | 2021-11-26 | 2023-06-01 | 广东邦普循环科技有限公司 | Nickel-rich high-voltage sodium-ion positive electrode material for battery, preparation method therefor, and application thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1723578A (en) * | 2001-04-06 | 2006-01-18 | 威伦斯技术公司 | Sodium ion batteries |
| CN106299299A (en) * | 2016-09-21 | 2017-01-04 | 哈尔滨工业大学 | A kind of anode material for lithium-ion batteries with surface hydrophobic and preparation method thereof |
| CN107895789A (en) * | 2017-11-28 | 2018-04-10 | 武汉理工大学 | Micron ball nano material of redox graphene cladding vanadium phosphate sodium and its preparation method and application |
-
2018
- 2018-09-03 CN CN201811019663.2A patent/CN110875473B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1723578A (en) * | 2001-04-06 | 2006-01-18 | 威伦斯技术公司 | Sodium ion batteries |
| CN106299299A (en) * | 2016-09-21 | 2017-01-04 | 哈尔滨工业大学 | A kind of anode material for lithium-ion batteries with surface hydrophobic and preparation method thereof |
| CN107895789A (en) * | 2017-11-28 | 2018-04-10 | 武汉理工大学 | Micron ball nano material of redox graphene cladding vanadium phosphate sodium and its preparation method and application |
Non-Patent Citations (2)
| Title |
|---|
| R. A. SHAKOOR等: "A combined first principles and experimental study on Na3V2(PO4)2F3 for rechargeable Na batteries", 《J. MATER. CHEM.》 * |
| WEIXIN SONG等: "Multifunctional dual Na3V2(PO4)2F3 cathode for both lithium-ion and sodium-ion batteries", 《RSC ADV.》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113614941A (en) * | 2020-10-19 | 2021-11-05 | 宁德新能源科技有限公司 | Electrochemical device and electronic device comprising same |
| WO2022082355A1 (en) * | 2020-10-19 | 2022-04-28 | 宁德新能源科技有限公司 | Electrochemical device and electronic device containing same |
| CN113614941B (en) * | 2020-10-19 | 2024-02-20 | 宁德新能源科技有限公司 | Electrochemical device and electronic device comprising same |
| RU2748159C1 (en) * | 2020-12-11 | 2021-05-20 | Автономная некоммерческая образовательная организация высшего образования "Сколковский институт науки и технологий" (Сколковский институт науки и технологий) | Electrode material for sodium-ion batteries, method of its production, electrode and battery based on the electrode material |
| WO2022177246A1 (en) * | 2021-02-19 | 2022-08-25 | 전남대학교산학협력단 | Carbon-coated nmtvp nanocomposite positive electrode material, method for manufacturing same, and positive electrode and sodium ion battery comprising same |
| CN113437276A (en) * | 2021-06-26 | 2021-09-24 | 宁德时代新能源科技股份有限公司 | Positive electrode active material, electrochemical device, and electronic device |
| WO2022267550A1 (en) * | 2021-06-26 | 2022-12-29 | 宁德时代新能源科技股份有限公司 | Positive electrode active material, electrochemical apparatus and electronic device |
| CN113745507A (en) * | 2021-09-02 | 2021-12-03 | 东北师范大学 | Vanadium-oxygen-sodium chlorophosphate cathode material, preparation method and sodium ion battery |
| CN113745507B (en) * | 2021-09-02 | 2024-01-30 | 东北师范大学 | Sodium vanadyl chlorophosphate positive electrode material, preparation method and sodium ion battery |
| CN114023921A (en) * | 2021-11-01 | 2022-02-08 | 惠州亿纬锂能股份有限公司 | Positive pole piece of sodium-ion battery and preparation method and application thereof |
| WO2023093180A1 (en) * | 2021-11-26 | 2023-06-01 | 广东邦普循环科技有限公司 | Nickel-rich high-voltage sodium-ion positive electrode material for battery, preparation method therefor, and application thereof |
| GB2619230A (en) * | 2021-11-26 | 2023-11-29 | Guangdong Brunp Recycling Technology Co Ltd | Nickel-rich high-voltage sodium-ion positive electrode material for battery, preparation method therefor, and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110875473B (en) | 2021-06-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110875473B (en) | Positive electrode active material, preparation method thereof and sodium ion battery | |
| CN111554919B (en) | Positive electrode active material, preparation method thereof and sodium ion battery | |
| Qu et al. | Porous LiMn 2 O 4 as cathode material with high power and excellent cycling for aqueous rechargeable lithium batteries | |
| Tang et al. | An aqueous rechargeable lithium battery of excellent rate capability based on a nanocomposite of MoO 3 coated with PPy and LiMn 2 O 4 | |
| CN111435740B (en) | Positive electrode active material, positive plate and sodium ion battery | |
| KR101494715B1 (en) | Negative active material for rechargeable lithium battery, method of preparing the same, and negative electrode and rechargeable lithium battery including the same | |
| CN115472818A (en) | Positive active material, positive pole piece and sodium ion battery | |
| CN111525099B (en) | Sodium ion battery | |
| EP2648250B1 (en) | Lithium manganese oxide positive active material for lithium ion secondary battery and lithium ion secondary battery including the same | |
| Li et al. | High performance porous MnO@ C composite anode materials for lithium-ion batteries | |
| CN104507865A (en) | Cathode active material and method of preparing the same | |
| CN101826617B (en) | Preparation method of lithium iron phosphate | |
| CN111435742A (en) | Positive active material, positive pole piece and sodium ion battery | |
| CN102637873A (en) | Lithium ion battery cathode material and method for preparing same | |
| JPWO2015141853A1 (en) | Carbonaceous molded body for electrode and method for producing the same | |
| CN104979541A (en) | Lithium titanate composite material and preparation method thereof | |
| WO2016158823A1 (en) | Carbonaceous molding for cell electrode, and method for manufacturing same | |
| CN111554905B (en) | Preparation method, product and application of zinc oxide-based carbon composite nano material | |
| CN109449440B (en) | Microporous ultrathin soft carbon nanosheet and preparation method and application thereof | |
| CN110931726A (en) | Lithium titanate negative electrode composite material, preparation method thereof and lithium ion battery | |
| CN113207315A (en) | Composite graphite material, secondary battery, device and preparation method | |
| CN110649261B (en) | Positive electrode active material, positive electrode sheet and sodium ion secondary battery | |
| Minakshi et al. | Multi-component olivine for lithium-ion hybrid capacitor | |
| CN113506867A (en) | MoS for lithium ion battery2N/N doped composite material and preparation method thereof | |
| KR20220064385A (en) | Composite graphite material and manufacturing method thereof, secondary battery and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |