CN117080430A - Sodium ion positive electrode material, sodium ion battery, and preparation methods and applications thereof - Google Patents

Sodium ion positive electrode material, sodium ion battery, and preparation methods and applications thereof Download PDF

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Publication number
CN117080430A
CN117080430A CN202311254813.9A CN202311254813A CN117080430A CN 117080430 A CN117080430 A CN 117080430A CN 202311254813 A CN202311254813 A CN 202311254813A CN 117080430 A CN117080430 A CN 117080430A
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positive electrode
sodium ion
heat treatment
sodium
lithium
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郭金泽
冯丽华
查惟伟
周晓崇
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Huzhou Chaona New Energy Technology Co ltd
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Huzhou Chaona New Energy Technology Co ltd
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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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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 invention discloses a sodium ion positive electrode material, a sodium ion battery and a preparation method and application thereof, and relates to the technical field of sodium ion batteries. The inventors creatively caused a certain amount of lithium to exist in the sodium ion battery system, and caused lithium to occupy sodium sites, and energy storage and conversion are performed in parallel with sodium. Compared with sodium ions, lithium ions have smaller radius size, and the migration rate in the anode and the cathode is faster, so that the energy storage and conversion device taking sodium as a main body can obtain higher discharge rate performance.

Description

Sodium ion positive electrode material, sodium ion battery, and preparation methods and applications thereof
Technical Field
The invention relates to the technical field of sodium ion batteries, in particular to a sodium ion positive electrode material, a sodium ion battery and a preparation method and application thereof.
Background
At present, lithium batteries are widely applied to the fields of mobile electronic equipment, electric automobiles and the like, and further application of the lithium ion batteries in the field of large-scale energy storage systems is limited to a certain extent due to extremely limited lithium resource reserves and uneven distribution in the crust. The sodium ion battery has a working principle similar to that of a lithium ion battery, and the sodium resource is rich and low in price, so that the requirement of a large-scale energy storage market can be met. Compared with a lithium ion battery, the sodium ion battery can theoretically exert higher multiplying power performance, and is extremely suitable for application scenes of high-power supplies.
However, the existing sodium ion battery technology cannot meet the requirement of high-rate charge and discharge performance, and is not particularly suitable for application in high-power working conditions of 10 ℃ or more. The positive electrode material is used as a key component of the sodium ion battery and plays a decisive role in the electrochemical performance of the sodium ion battery. The positive electrode materials of the sodium ion battery at present mainly comprise polyanions, prussian and layered oxides. Among them, layered oxide materials have higher theoretical specific capacity and energy density, and are attracting attention of researchers. Compared with other main stream sodium ion positive electrode materials, the layered oxide has wider interlayer spacing, and the intrinsic structure is favorable for meeting the rapid migration of sodium ions in a bulk phase structure.
At present, the technical research on layered oxides mainly focuses on modification of transition metal layers, which have the general formula Na x MO 2 M comprises Li + ，Ni 2+ ，Mg 2+ ，Zn 2+ ，Co 2+ ，Ca 2 +，Ba 2+ ，Sr 2+ ，Al 3+ ，B 3+ ，Cr 3+ ，Co 3+ ，V 3+ ，Zr 4+ ，Ti 4+ ，Sn 4 + ，V 4+ ，Mo 5+ ，Mo 6+ ，Ru 4+ ，Nb 5+ ，Si 4+ ，Sb 5+ ，Nb 5+ ，Mo 6+ ，Te 6+ One or more of (a) and (b). The ion doping of the transition metal layer can improve the stability of the structure of the layered oxide anode material, adjust the chemical bond energy between the transition metal and oxygen, and realizeLong cycle life of sodium ion batteries. In addition, the migration speed of sodium ions in the sodium layer is closely related to the rate capability of the sodium ion battery, and the migration speed of sodium ions in the sodium layer is mainly improved by improving the spacing of the sodium layer at present.
In addition, another way to design high power batteries is to adjust the appropriate process parameters. It is well known that the coating quality and the compaction density of electrode sheets are closely related to the transport of ions. The ion transport rate can be greatly improved by adopting the ultra-low coating amount and the low compaction density, which is beneficial to obtaining the high power performance of the battery. For example, patent CN 113745639a uses small particles of lithium nickel cobalt manganese oxide positive electrode material for manufacturing a start-stop battery, D 50 The size is 2-8.5 mu m, and the single-sided coating density of the positive electrode is 5.1-9.5 mg/cm 2 The single-sided coating of the cathode is 2.8-5.2 mg/cm 2 . Besides, the adoption of the high-porosity diaphragm and the high-conductivity electrolyte is also beneficial to realizing the rapid transportation of sodium ions and obtaining the sodium ion battery with high power performance.
However, the positive electrode material of the sodium ion battery obtained by the existing improved method cannot better meet the requirement of a high-power battery, and the multiplying power performance is still to be improved.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to provide a sodium ion positive electrode material, a sodium ion battery and a preparation method and application thereof, and aims to enable the sodium ion battery to obtain higher rate capability and meet the requirement of a high-power battery.
The invention is realized in the following way:
in a first aspect, the present invention provides a sodium ion positive electrode material having the general formula Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element.
In an alternative embodiment, the ion corresponding to M in the formula is selected from Li + 、Ni 2+ 、Mg 2+ 、Zn 2+ 、Co 2+ 、Ca 2+ 、Ba 2 + 、Sr 2+ 、Al 3+ 、B 3+ 、Cr 3+ 、Co 3+ 、V 3+ 、Zr 4+ 、Ti 4+ 、Sn 4+ 、V 4+ 、Mo 5+ 、Mo 6+ 、Ru 4+ 、Nb 5+ 、Si 4+ 、Sb 5+ 、Nb 5+ 、Mo 6+ And Te (Te) 6+ At least one of (a) and (b);
preferably, the ion corresponding to M in the formula is selected from Ni 2+ And Mg (magnesium) 2+ At least one of (a) and (b);
preferably, the particle size of the sodium ion positive electrode material is 1 to 20 μm.
In a second aspect, the present invention provides a method for preparing a sodium ion positive electrode material according to the foregoing embodiment, including: and carrying out heat treatment on the mixed material formed by the lithium source, the M source and the sodium source.
In an alternative embodiment, the heat treatment comprises: carrying out primary heat treatment on the mixed material, grinding the material obtained by the primary heat treatment, and then carrying out secondary heat treatment;
preferably, the treatment temperature of the primary heat treatment is 750-800 ℃ and the treatment time is 10-15h;
preferably, the treatment temperature of the secondary heat treatment is 750-800 ℃ and the treatment time is 10-15h.
In an alternative embodiment, the process for preparing the mixture comprises: mixing and ball milling a lithium source, an M source and a sodium source in proportion;
preferably, the solvent is added before ball milling for stirring;
more preferably, the solvent comprises ethanol and water.
In a third aspect, the invention provides a sodium ion battery, comprising a positive electrode plate, wherein the general formula of a sodium ion positive electrode material on the positive electrode plate is Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element.
In a fourth aspect, the present invention provides a method for preparing a sodium ion battery according to the foregoing embodiment, including: preparing a sodium ion positive electrode material meeting the general formula, and preparing a positive electrode plate by using the prepared sodium ion positive electrode material;
preferably, the preparation process of the sodium ion positive electrode material comprises the following steps: carrying out heat treatment on a mixed material formed by a lithium source, an M source and a sodium source;
more preferably, the heat treatment comprises: carrying out primary heat treatment on the mixed material, grinding the material obtained by the primary heat treatment, and then carrying out secondary heat treatment; further preferably, the treatment temperature of the primary heat treatment is 750-800 ℃ and the treatment time is 10-15h; further preferably, the treatment temperature of the secondary heat treatment is 750-800 ℃ and the treatment time is 10-15h; further preferably, in the primary heat treatment and the secondary heat treatment, the dew point temperature of the environment where the material is located is less than or equal to-25 ℃;
more preferably, the process for preparing the mixture comprises: mixing and ball milling a lithium source, an M source and a sodium source in proportion; further preferably, the solvent is added before ball milling for stirring; the solvent includes ethanol and water.
In a fifth aspect, the present invention provides a method for preparing a sodium ion battery according to the foregoing embodiment, including: mixing a carbon material and a lithium source, performing heat treatment to obtain a mixed sample, and coating the mixed sample, a conductive agent and a binder on a negative current collector to form a negative electrode plate;
coating a layered oxide, a conductive agent and a binder on a positive current collector to form a positive electrode plate; wherein the general formula of the lamellar oxide is Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, M represents a metal element;
assembling the obtained positive pole piece and negative pole piece to form a battery;
preferably, the preparation process of the mixed sample comprises: the carbon material and the lithium source are mixed according to the mass ratio of (10-15): 1, and preserving the temperature for 12-24 hours at 600-800 ℃; more preferably, the carbon material is selected from at least one of hard carbon and soft carbon; more preferably, the lithium source is selected from at least one of lithium oxalate, lithium carbonate, lithium squarate, and lithium nitrate;
preferably, the positive electrode current collector is an aluminum foil;
preferably, the negative electrode current collector is selected from at least one of aluminum foil and copper foil.
In a sixth aspect, the present invention provides a method for preparing a sodium-ion battery according to the foregoing embodiment, comprising: coating a layered oxide, a conductive agent and a binder on a positive current collector to form a positive electrode plate; wherein the general formula of the lamellar oxide is Na 1- x MO 2 X is more than 0 and less than or equal to 0.2, M represents a metal element;
assembling the positive electrode plate, the negative electrode plate and the electrolyte to form a battery;
wherein the electrolyte contains LiPF 6 And NaPF (NaPF) 6 ；
Preferably, the anode active material on the anode tab is selected from at least one of hard carbon and soft carbon.
In a seventh aspect, the present invention provides an electrical energy storage device comprising a sodium-ion battery according to the foregoing embodiment or a sodium-ion battery prepared by the method of any one of the foregoing embodiments.
The invention has the following beneficial effects: the inventors creatively caused a certain amount of lithium to exist in the sodium ion battery system, and caused lithium to occupy sodium sites, and energy storage and conversion are performed in parallel with sodium. Compared with sodium ions, lithium ions have smaller radius size, and the migration rate in the anode and the cathode is faster, so that the energy storage and conversion device taking sodium as a main body can obtain higher discharge rate performance.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a diagram of Li provided in example 1 of the present invention 0.1 Na 0.9 Ni 1/3 Fe 1/3 Mn 1/3 O 2 An XRD pattern of (a);
FIG. 2 is a diagram of Li provided in example 2 of the present invention 0.1 Na 0.9 Zn 0.05 Ni 0.317 Mn 0.317 Fe 0.317 O 2 SEM images of (a);
fig. 3 is a high-power charge-discharge graph provided in embodiment 3 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The embodiment of the invention provides a sodium ion positive electrode material, which has a general formula of Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element. Lithium is introduced into the sodium ion positive electrode material, part of sodium sites are occupied by the lithium, and because the radius of lithium ions is smaller, the material structure change caused when the positive and negative electrode materials are subjected to deintercalation is smaller, so that the high-power sodium ion battery has better cycle life.
Specifically, the value of x may be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, etc.
Further, the ion corresponding to M in the general formula is selected from Li + 、Ni 2+ 、Mg 2+ 、Zn 2+ 、Co 2+ 、Ca 2+ 、Ba 2+ 、Sr 2+ 、Al 3+ 、B 3+ 、Cr 3+ 、Co 3+ 、V 3+ 、Zr 4+ 、Ti 4+ 、Sn 4+ 、V 4+ 、Mo 5+ 、Mo 6+ 、Ru 4+ 、Nb 5+ 、Si 4+ 、Sb 5+ 、Nb 5+ 、Mo 6+ And Te (Te) 6+ The ion corresponding to M can be any one or more of the above. Preferably, the ion corresponding to M in the formula is selected from Ni 2+ And Mg (magnesium) 2+ By preference for M, it is advantageous to further improve the electrochemical properties of the material.
In some embodiments, the particle size of the sodium ion positive electrode material is 1-20 μm, such as may be 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, 20 μm, etc. The sodium ion positive electrode material may be monocrystalline or polycrystalline.
The embodiment of the invention also provides a sodium ion battery, which comprises a positive electrode plate, wherein the general formula of the sodium ion positive electrode material on the positive electrode plate is Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element. By introducing a certain amount of lithium into the battery system, energy storage and conversion are performed in parallel with sodium. Compared with sodium ions, lithium ions have smaller radius size, and the migration rate in the anode and the cathode is faster, so that the energy storage and conversion device taking sodium as a main body can obtain higher discharge rate performance.
The ion species corresponding to M are referred to above, and will not be repeated here.
The embodiment of the invention also provides a preparation method of the sodium ion battery, wherein the general formula of the sodium ion positive electrode material on the positive electrode plate in the prepared sodium ion battery is Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element. The preparation method mainly comprises the following three types:
in a first method, lithium is directly introduced into the positive electrode material.
Firstly, preparing a positive electrode material meeting the general formula of a sodium ion positive electrode material, and then forming a battery structure. The method comprises the following specific steps:
(1) Preparation of sodium ion cathode Material
And carrying out heat treatment on a mixed material formed by the lithium source, the M source and the sodium source, wherein the dosage proportion of the lithium source, the M source and the sodium source meets the requirement of a general formula.
In some embodiments, the process for preparing the mixture comprises: mixing and ball milling a lithium source, an M source and a sodium source according to a proportion so as to uniformly mix the components. The ball milling can be carried out by adopting a wet ball milling mode, and a solvent is added for stirring before the ball milling; the solvent can comprise ethanol and water, the proportion of the ethanol and the water is not limited, and the volume ratio can be 1:0.5-1.5; the total dosage of the solvent is not limited, and the mass ratio of the mixed solvent to the solid raw material can be controlled to be 0.8:1-1:1.5.
In some embodiments, the heat treatment comprises: and (3) carrying out primary heat treatment on the mixed material, grinding the material obtained by the primary heat treatment, and then carrying out secondary heat treatment. After the primary heat treatment, the materials may have caking and the like, and the secondary heat treatment is carried out after grinding, so that the reaction is more complete.
Further, the treatment temperature of the primary heat treatment is 750-800 ℃ and the treatment time is 10-15h; the treatment temperature of the secondary heat treatment is 750-800 ℃ and the treatment time is 10-15h. The temperature of the primary heat treatment may be the same or different, and is preferably controlled within the above range, and specifically 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃, 800 ℃ and the like; the treatment time of the primary heat treatment and the secondary heat treatment may be the same or different, and the treatment time may be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, or the like, while controlling the above-mentioned range.
Further, the primary heat treatment and the secondary heat treatment can be carried out in an air atmosphere, the dew point temperature of the environment where the materials are positioned is less than or equal to minus 25 ℃, and the sodium ion positive electrode material is suitable for being prepared in a dry environment due to special properties, so that the reaction is prevented from being interfered by moisture.
(2) Forming a battery
And preparing the prepared sodium ion positive electrode material to form a positive electrode plate, and assembling the positive electrode plate, the negative electrode plate and the electrolyte to form the battery. The process of preparing the positive electrode plate can refer to the prior art, and the positive electrode plate can be obtained by mixing and homogenizing a sodium ion positive electrode material, a conductive agent and a binder, coating the mixture on a positive electrode current collector (such as aluminum foil), and drying the mixture to form an active coating.
The types of the negative electrode sheet and the electrolyte are not limited, and the negative electrode sheet and the electrolyte of the existing sodium ion battery can be adopted.
And secondly, introducing lithium into the negative electrode plate.
And the layered oxide with sodium deficiency is used as an anode active material, lithium is introduced into a cathode pole piece, and lithium can enter sodium position through electrochemical reaction in the use process of the battery, so that the anode material of the sodium ion battery meeting the general formula requirement is formed. The method comprises the following specific steps:
(1) Preparation of negative electrode sheet
And mixing the carbon material with a lithium source, performing heat treatment to obtain a mixed sample, and coating the mixed sample, the conductive agent and the binder on the negative current collector to form a negative electrode plate. In preparing the mixed sample, lithium in the lithium source can be reduced during heat treatment by utilizing the reducibility of the carbon material; the carbon material also has the properties of conductivity and sodium storage during use.
In some embodiments, the process of preparing the mixed sample comprises: mixing the carbon material and the lithium source according to the mass ratio (10-15) of 1, and then preserving the heat for 12-24 hours at 600-800 ℃ to fully carry out the reaction. Specifically, the mass ratio of the carbon material to the lithium source may be 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, etc., the heat treatment temperature may be 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, etc., the heat preservation time may be 12 hours, 15 hours, 20 hours, 24 hours, etc., and the heating rate in the heating process may be about 5 ℃/min.
In some embodiments, the carbon material is selected from at least one of hard carbon and soft carbon, either hard carbon or soft carbon, or a mixture of both. The lithium source is at least one selected from lithium oxalate, lithium carbonate, lithium squarate and lithium nitrate, and can be any one or more of the above.
In some embodiments, the negative electrode current collector is selected from at least one of aluminum foil and copper foil, and may be any of the above.
In some embodiments, the specific types of the conductive agent and the binder are not limited, and may be general raw material types, for example, the conductive agent may be carbon nanotubes, graphene, ketjen black, etc., and the binder may be polyvinylidene fluoride (PVDF), etc.
(2) Preparation of positive electrode sheet
Coating a layered oxide, a conductive agent and a binder on a positive current collector to form a positive electrode plate; wherein the general formula of the lamellar oxide is Na 1-x MO 2 0 < x.ltoreq.0.2, M represents a metal element (for specific species, refer to the above). And the layered oxide with sodium deficiency is used as an anode active material, and lithium on a cathode plate of the finally obtained battery can enter the anode material to occupy sodium in the use process.
In some embodiments, the positive electrode current collector is at least one of aluminum foils, and may be any of the above.
In some embodiments, the specific kind and amount of the conductive agent and the binder are not limited, and may be a common raw material type, for example, the conductive agent may be carbon nanotubes, graphene, ketjen black, etc., and the binder may be polyvinylidene fluoride (PVDF), etc.
(3) Assembled battery
The battery is assembled by using the obtained positive electrode plate, negative electrode plate, electrolyte and the like, and the specific type of the electrolyte is not limited. Cutting the electrode plate, and sequentially filling the electrode plate into gaskets according to the negative electrode, the diaphragm and the positive electrode to obtain Li x Na 1-x MO 2 And a soft package battery.
And thirdly, introducing lithium into the electrolyte.
By using a layered oxide lacking sodium as a positive electrode active material, lithium occupies the sodium site during use of the battery by introducing lithium into the electrolyte. Specifically, the method comprises the following steps:
s1, preparing a positive pole piece
Coating a layered oxide, a conductive agent and a binder on a positive electrode current collector to form a positive electrode plate, wherein the general formula of the layered oxide is Na 1-x MO 2 0 < x.ltoreq.0.2, M represents a metal element (for specific species, refer to the above). And the layered oxide with sodium deficiency is used as an anode active material, and lithium on electrolyte of the finally obtained battery can enter the anode material to occupy sodium position in the using process.
In some embodiments, the positive current collector is aluminum foil.
In some embodiments, the specific kind and amount of the conductive agent and the binder are not limited, and may be a common raw material type, for example, the conductive agent may be carbon nanotubes, graphene, ketjen black, etc., and the binder may be polyvinylidene fluoride (PVDF), etc.
S2, assembled battery
Assembling the positive electrode plate, the negative electrode plate and the electrolyte to form a battery; wherein the electrolyte contains LiPF 6 The specific content is not limited, and the lithium content is sufficient to increase the lithium content, and the LiPF 6 The ratio of (c) may be 0% to 100% (excluding the end point values).
The specific type of the negative electrode sheet is not limited, and the negative electrode active material on the negative electrode sheet is at least one selected from hard carbon and soft carbon, and can be any one or more of the above.
It should be noted that the above three methods for preparing sodium ion batteries are provided, which can effectively improve the rate performance of the battery. If the lithium-containing layered oxide positive electrode and the sodium-containing layered oxide positive electrode are mixed for pulping and coating, sodium ions are easy to enter the lithium-containing layered oxide material, collapse of the material structure is caused, and rapid decay of electrochemical performance occurs. In addition, when the lithium-containing layered oxide and the sodium-containing layered oxide are mixed as a positive electrode active material, the mixed layered oxide has a large number of interfaces, and side reactions with the electrolyte are increased. In the three methods provided by the embodiment of the invention, lithium ions are inserted into the existing sodium ion battery material and structure system, which is beneficial to the stabilization of the sodium-containing layered anode material and hard carbon structure. And the layered oxide containing sodium and the hard carbon have larger interlayer spacing than the layered oxide containing lithium and the graphite respectively, so that the resistance of lithium ions in a bulk phase is smaller, more lithium ions can be accommodated for intercalation and deintercalation, and the rate capability is higher.
The embodiment of the invention also provides an electric device which comprises the sodium ion battery and can also comprise an electric device, wherein the sodium ion battery is used for supplying power to the electric device, and the specific type of the electric device is not limited.
The features and capabilities of the present invention are described in further detail below in connection with the examples.
Example 1
The embodiment provides a preparation method of a sodium ion battery, which comprises the following steps:
(1) Selecting layered oxide Na 0.9 Ni 1/3 Fe 1/3 Mn 1/3 O 2 As a positive electrode material. The preparation process comprises the following steps: mixing sodium carbonate, nickel oxide, ferric oxide and manganese oxide according to a mole ratio, adding a mixed solvent formed by ethanol and water, uniformly stirring, transferring into a ball milling tank, performing high-energy ball milling at a rotating speed of 1200r/min for 2h; wherein, the dosage of the mixed solvent and the mixed raw materialThe mass ratio of the materials is 0.8:1, and the volume ratio of the ethanol to the water is 1:1; carrying out primary heat treatment on the mixed material, grinding the material obtained by the primary heat treatment, and then carrying out secondary heat treatment; the treatment temperature of the primary heat treatment is 800 ℃ and the treatment time is 15 hours; the treatment temperature of the secondary heat treatment is 750 ℃ and the treatment time is 15 hours, and finally the anode material Na is obtained 0.9 Ni 1/3 Fe 1/ 3 Mn 1/3 O 2 。
(2) The hard carbon and lithium oxalate were put into a mortar, and ground to obtain a mixture.
(3) And (3) putting the mixture obtained in the step (2) into a tubular furnace, performing heat treatment under the condition of continuously introducing protective gas, wherein the heat treatment temperature is 600 ℃, the heat preservation time is 12h, the heating rate is 5 ℃/min, and then cooling along with the furnace.
(4) Na is mixed with 0.9 Ni 1/3 Fe 1/3 Mn 1/3 O 2 Mixing with conductive agent (carbon nano tube) and binder (PVDF) according to the mass ratio of 96% to 2%, adding N-methyl pyrrolidone to obtain positive electrode slurry, coating the positive electrode slurry on the front and back surfaces of aluminium foil with thickness of 15 μm, and controlling surface density to 280g/m 2 And drying to form the positive pole piece. Meanwhile, mixing the material obtained in the step (3) with a conductive agent (conductive carbon black), a binder (CMC and SBR) according to the mass ratio of 95.5 percent to 1.5 percent to 1 percent to 2 percent, adding deionized water to obtain negative electrode slurry, homogenizing, coating the negative electrode slurry on the front side and the back side of an aluminum foil with the thickness of 15 mu m, and controlling the areal density to be 120g/m 2 And drying to form the negative electrode plate.
(5) Cutting the electrode sheet obtained in the step (4), and sequentially forming a 2Ah soft-packaged battery according to a negative electrode, a diaphragm (PP+single-sided coated ceramic) and a positive electrode;
performance test:
(1) The 2Ah soft package battery is subjected to formation and capacity division by adopting 0.05C current, and the positive electrode is Li after the formation 0.1 Na 0.9 Ni 1/3 Fe 1/3 Mn 1/3 O 2 The XRD patterns of the positive electrode materials of the high-power soft-package battery are shown in figure 1 after the positive electrode materials are stripped.
(2) Tested by testingIn this embodiment, li is prepared in situ electrochemically 0.1 Na 0.9 Ni 1/3 Fe 1/3 Mn 1/3 O 2 The battery has a discharge capacity of 90% in 40C discharge capacity retention rate.
Example 2
The embodiment provides a preparation method of a sodium ion battery, which comprises the following steps:
(1) Lithium carbonate, nickel oxide, ferric oxide, manganese oxide, zinc oxide and sodium carbonate are weighed and mixed according to the mol ratio of 0.05:0.317:0.317:0.317:0.05:0.45, added into a mixed solvent of ethanol and water, stirred and transferred into a ball milling tank, and subjected to high-energy ball milling at the rotating speed of 1200r/min for 2 hours, so as to obtain a mixed sample. Wherein the mass ratio of the dosage of the mixed solvent to the mixed raw materials is 1:1, and the volume ratio of the ethanol to the water is 1:1.
(2) And (3) placing the mixed sample obtained in the step (1) into a muffle furnace, and performing heat treatment at 800 ℃ in an air atmosphere, wherein the heating rate is 5 ℃/min, the heat preservation time is 12h, and cooling along with the furnace to obtain an initial sample, and the temperature of the environment is required to be not higher than-25 ℃.
(3) Grinding the powder sample obtained in the step (2), repeating the second operation to finally obtain the positive electrode Li 0.1 Na 0.9 Zn 0.05 Ni 0.317 Mn 0.317 Fe 0.317 O 2 Positive electrode material for high-power sodium ion battery.
Performance test: SEM images of the positive electrode materials prepared in this example were tested, and the results are shown in fig. 2. This example can successfully prepare Li 0.1 Na 0.9 Zn 0.05 Ni 0.317 Mn 0.317 Fe 0.317 O 2 Layered oxide positive electrode, single crystal structure, P 2 /O 3 Phase mixed phase, uniform particles, and dimension of 2-15 μm, d 50 The material can be used as a positive electrode material of a sodium ion battery, has a 40C discharge capacity retention rate of 88%, and has good cycle life.
Example 3
The embodiment provides a preparation method of a sodium ion battery, which comprises the following steps:
(1) Selecting layered oxide Na 0.8 Ni 1/3 Fe 1/3 Mn 1/3 O 2 As a positive electrode material. The preparation process comprises the following steps: mixing sodium carbonate, nickel oxide, ferric oxide and manganese oxide according to a mole ratio, adding a mixed solvent formed by ethanol and water, uniformly stirring, transferring into a ball milling tank, performing high-energy ball milling at a rotating speed of 1200r/min for 2h; the mass ratio of the consumption of the mixed solvent to the mixed raw materials is 1.5:1, the volume ratio of the ethanol to the water is 1:1, the mixed raw materials are subjected to primary heat treatment, the materials obtained by the primary heat treatment are ground, and then the secondary heat treatment is carried out; the treatment temperature of the primary heat treatment is 750 ℃ and the treatment time is 12 hours; the treatment temperature of the secondary heat treatment is 800 ℃ and the treatment time is 15 hours, and finally the anode material Na is obtained 0.8 Ni 1/3 Fe 1/ 3 Mn 1/3 O 2 。
(2) Na is mixed with 0.8 Ni 1/3 Fe 1/3 Mn 1/3 O 2 Mixing with conductive agent (Ketjen black) and binder (PVDF) at a mass ratio of 96% to 2%, adding N-methyl pyrrolidone, homogenizing to obtain positive electrode slurry, coating the positive electrode slurry on the front and back surfaces of aluminum foil with thickness of 15 μm, and controlling surface density to 280g/m 2 And drying to form the positive pole piece.
(3) The method comprises the steps of taking hard carbon as an anode active material, mixing the hard carbon with a conductive agent (conductive carbon black) and a binder (CMC+SBR) according to the mass ratio of 95.5 percent to 1.5 percent to 1 percent to 2 percent, adding deionized water for homogenating to obtain anode slurry, coating the anode slurry on the front side and the back side of an aluminum foil with the thickness of 15 mu m, and controlling the surface density to be 120g/m 2 And drying to form the negative electrode plate.
(4) Containing LiPF 6 Sodium ion electrolyte of (3), liPF 6 The mass ratio of the electrolyte in the total electrolyte is 20%, and the balance is 5%.
(5) The electrode plate is cut, and the 2Ah soft package battery is formed by sequentially forming a negative electrode, a diaphragm (PP+single-sided ceramic) and a positive electrode.
Performance test: the battery prepared in this example was tested for a high power charge-discharge curve as shown in fig. 3. The implementation isThe lithium-containing high-power sodium ion battery system can be successfully realized by the method, and the positive electrode material for completing the first-circle charge and discharge is converted into Li 0.2 Na 0.8 Ni 1/3 Fe 1/3 Mn 1/3 O 2 The discharge reaches 92% at a large rate of 40C, and the high-efficiency high-power discharge lamp has good cycle stability.
Comparative example 1
The only difference from example 1 is that: the positive electrode material is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Lithium is not introduced in the preparation process of the negative electrode plate.
Performance test: the battery has a discharge capacity of up to 75% in 40C discharge capacity retention rate.
Comparative example 2
The only difference from example 2 is that: lithium is not introduced during the preparation of the positive electrode material, and the chemical formula of the prepared positive electrode material is NaZn 0.05 Ni 0.317 Mn 0.317 Fe 0.317 O 2 。
Performance test: the 40C discharge capacity retention rate reaches 60 percent
Comparative example 3
The only difference from example 3 is that: the chemical formula of the positive electrode material is NaNi 1/3 Fe 1/3 Mn 1/3 O 2 。
Performance test: discharge reaches 80% under 40C high multiplying power
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A sodium ion positive electrode material is characterized in that the general formula is Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element.
2. The positive electrode material according to claim 1, wherein the ion corresponding to M in the formula is selected from Li + 、Ni 2+ 、Mg 2+ 、Zn 2+ 、Co 2+ 、Ca 2+ 、Ba 2+ 、Sr 2+ 、Al 3+ 、B 3+ 、Cr 3+ 、Co 3+ 、V 3+ 、Zr 4+ 、Ti 4+ 、Sn 4+ 、V 4+ 、Mo 5+ 、Mo 6+ 、Ru 4+ 、Nb 5+ 、Si 4+ 、Sb 5+ 、Nb 5+ 、Mo 6+ And Te (Te) 6+ At least one of (a) and (b);
preferably, the ion corresponding to M in the formula is selected from Ni 2+ And Mg (magnesium) 2+ At least one of (a) and (b);
preferably, the particle size of the sodium ion positive electrode material is 1-20 μm.
3. A method for preparing the sodium ion positive electrode material according to claim 1 or 2, comprising: and carrying out heat treatment on the mixed material formed by the lithium source, the M source and the sodium source.
4. A method of preparing according to claim 3, wherein the heat treatment comprises: carrying out primary heat treatment on the mixed material, grinding the material obtained by the primary heat treatment, and then carrying out secondary heat treatment;
preferably, the treatment temperature of the primary heat treatment is 750-800 ℃ and the treatment time is 10-15h;
preferably, the treatment temperature of the secondary heat treatment is 750-800 ℃ and the treatment time is 10-15h.
5. A method of preparing a mixture according to claim 3, wherein the process of preparing the mixture comprises: mixing and ball milling a lithium source, an M source and a sodium source in proportion;
preferably, the solvent is added before ball milling for stirring;
more preferably, the solvent includes ethanol and water.
6. A sodium ion battery is characterized by comprising a positive electrodeThe general formula of the sodium ion positive electrode material on the positive electrode sheet is Li x Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, and M represents a metal element.
7. A method of making a sodium ion battery of claim 6, comprising: preparing a sodium ion positive electrode material meeting the general formula, and preparing the positive electrode plate by using the prepared sodium ion positive electrode material;
preferably, the preparation process of the sodium ion positive electrode material comprises the following steps: carrying out heat treatment on a mixed material formed by a lithium source, an M source and a sodium source;
more preferably, the heat treatment includes: carrying out primary heat treatment on the mixed material, grinding the material obtained by the primary heat treatment, and then carrying out secondary heat treatment; further preferably, the treatment temperature of the primary heat treatment is 750-800 ℃ and the treatment time is 10-15h; further preferably, the treatment temperature of the secondary heat treatment is 750-800 ℃ and the treatment time is 10-15h; further preferably, in the primary heat treatment and the secondary heat treatment, the dew point temperature of the environment where the material is located is less than or equal to-25 ℃;
more preferably, the process for preparing the mixture comprises: mixing and ball milling a lithium source, an M source and a sodium source in proportion; further preferably, the solvent is added before ball milling for stirring; the solvent includes ethanol and water.
8. A method of making a sodium ion battery of claim 6, comprising: mixing a carbon material and a lithium source, performing heat treatment to obtain a mixed sample, and coating the mixed sample, a conductive agent and a binder on a negative current collector to form a negative electrode plate;
coating a layered oxide, a conductive agent and a binder on a positive current collector to form a positive electrode plate; wherein the general formula of the layered oxide is Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, M represents a metal element;
assembling the obtained positive electrode plate and the obtained negative electrode plate to form a battery;
preferably, the preparation process of the mixed sample comprises the following steps: the carbon material and the lithium source are mixed according to the mass ratio of (10-15): 1, and preserving the temperature for 12-24 hours at 600-800 ℃; more preferably, the carbon material is selected from at least one of hard carbon and soft carbon; more preferably, the lithium source is selected from at least one of lithium oxalate, lithium carbonate, lithium squarate, and lithium nitrate;
preferably, the positive electrode current collector is aluminum foil;
preferably, the negative electrode current collector is selected from at least one of aluminum foil and copper foil.
9. A method of making a sodium ion battery of claim 6, comprising: coating a layered oxide, a conductive agent and a binder on a positive current collector to form a positive electrode plate; wherein the general formula of the layered oxide is Na 1-x MO 2 X is more than 0 and less than or equal to 0.2, M represents a metal element;
assembling the positive electrode plate, the negative electrode plate and the electrolyte to form a battery;
wherein the electrolyte contains LiPF 6 And NaPF (NaPF) 6 ；
Preferably, the negative active material on the negative electrode sheet is selected from at least one of hard carbon and soft carbon.
10. An electrical device comprising the sodium ion battery of claim 6 or the sodium ion battery prepared by the preparation method of any one of claims 7-9.
CN202311254813.9A 2023-09-26 2023-09-26 Sodium ion positive electrode material, sodium ion battery, and preparation methods and applications thereof Pending CN117080430A (en)

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