CN115148989A - Lithium ion battery positive electrode active material based on low-valence multi-electron transfer redox active metal element and preparation method and application thereof - Google Patents

Lithium ion battery positive electrode active material based on low-valence multi-electron transfer redox active metal element and preparation method and application thereof Download PDF

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CN115148989A
CN115148989A CN202210978353.3A CN202210978353A CN115148989A CN 115148989 A CN115148989 A CN 115148989A CN 202210978353 A CN202210978353 A CN 202210978353A CN 115148989 A CN115148989 A CN 115148989A
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lithium ion
ion battery
active material
valence
positive electrode
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纪效波
梅雨
侯红帅
邹国强
邓文韬
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Central South University
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Central South University
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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
    • 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
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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 provides a lithium ion battery anode active material based on a low-valence multi-electron transfer redox active metal element, which is characterized in that the lithium ion battery anode active material has a structural general formula as follows: li x (M 1 M 2 ) 2‑x O 2 Wherein, M is 1 A metal element having a multiple electron redox activity which is in a low valence state; m 2 The metal element is high-valence redox inert metal element, x is more than 0 and less than 2, the crystal structure of the lithium ion battery anode active material is a rock salt structure, the space point group is Fm-3m, and the anion and cation of the lithium ion battery anode active material are separatedThe total number of sub-charges is balanced. The lithium ion battery anode active material has high specific capacity and energy density, has excellent cycle performance, can be used in the fields of 3C products, electric automobiles and the like, and has good application prospect.

Description

Lithium ion battery positive electrode active material based on low-valence multi-electron transfer redox active metal element and preparation method and application thereof
Technical Field
The invention relates to the technical field of lithium ion battery anode materials, in particular to a lithium ion battery anode active material based on low-valence multi-electron transfer redox active metal elements and a preparation method and application thereof.
Background
The dependence of the 19 th century, fossil energy sources such as coal, petroleum and natural gas support the progress of human civilization and the development of economy and society. However, the non-regenerability of fossil energy and its enormous human consumption have made fossil energy gradually exhausted, with increasingly serious ecological problems. Under such an era background, it has become common human beings to develop new renewable, sustainable, and environmentally friendly energy sources. Among them, lithium ion batteries have been widely used in the fields of 3C products and electric vehicles because of their advantages of high specific energy, no memory effect, small self-discharge, long cycle life, and environmental friendliness. However, the capacity of the current lithium ion battery is limited by the anode material, and the demand of the development of the long-endurance electric vehicle is difficult to be well met. Therefore, the development of high capacity positive electrode materials is of great significance.
The energy storage and release of the lithium ion battery are realized in the form of oxidation-reduction reaction of an electrode material, and along with the insertion and extraction of lithium ions in the electrode material, the electrode material plays dual roles of electron migration and lithium ion transmission in the charge and discharge processes. Taking the positive electrode material as an example, during the charging process of the battery, lithium ions are extracted from the crystal lattice of the positive electrode material, and the valence state of the active element is increased along with the oxidation reaction to provide charge compensation. At the same time, electrons flow from the positive electrode to the negative electrode through an external circuit. When the battery is discharged as a power source after the battery is charged, lithium ions are inserted into the positive electrode material, electrons flow from the negative electrode to the positive electrode through an external circuit, and the reduction reaction of the active element in the positive electrode material is accompanied by a decrease in the valence. It can be seen that reversible redox of the active element provides storage and release of electrons for the positive electrode, which is a source of the capacity of the positive electrode material. The currently studied or widely used lithium ion battery positive electrode material only has high valence active elements, such as: the valence states of Ni, co and Mn elements in the ternary material are respectively 3+,3+ and 4+, mn in the lithium manganate material is a 3+/4+ mixed valence state, co in the lithium cobaltate material is 3+, and the lithium cobaltate material only has single electron transfer capacity, so that the capacity improvement of the anode material is limited.
Disclosure of Invention
Based on the above technical problems in the prior art, the inventors found in their research that the cation disordered rock salt structure has the advantage of wide composition space, and can accommodate lithium ions and low-valent transition metal ions with small radius difference at a cation site, so that the low-valent transition metal ions can be used as redox active centers to realize multi-electron transfer. Based on the above, one of the objects of the present invention is to provide a lithium ion battery positive electrode active material based on a low-valence multi-electron transfer redox active metal element, wherein the structural general formula of the lithium ion battery positive electrode active material is Li x (M 1 M 2 ) 2-x O 2 Wherein M is 1 A metal element having a multiple electron redox activity which is in a low valence state; m is a group of 2 The lithium ion battery anode active material is a high-valence redox inert metal element, x is more than 0 and less than 2, the crystal structure of the lithium ion battery anode active material is a rock salt structure, the space point group is Fm-3m, and the total number of the charges of anions and cations of the metal oxide is balanced.
In some embodiments, 1 ≦ x < 1.5.
In some embodiments, said M 1 Is Co 2+ 、Mn 2+ 、Ni 2+ 、Cr 3+ 、V 3+ 、 Mo 3+ 、Fe 2+ At least one of; said M 2 Is Ti 4+ 、Zr 4+ 、Mn 4+ 、Nb 5+ 、Ta 5+ 、W 6+ 、Mo 6+ At least one of (1).
In some embodiments, the M is 1 Is Co 2+ 、Mn 2+ 、Ni 2+ 、Cr 3+ 、V 3+ 、 Mo 3+ 、Fe 2+ One of (1), M 2 Is Ti 4 + 、Zr 4+ 、Mn 4+ 、Nb 5+ 、Ta 5+ 、W 6+ 、Mo 6+ And M is one of 1 And M 2 Are different elements.
A second object of the present invention is to provide a method for preparing a lithium ion battery positive electrode active material based on a low-valence multiple-electron transfer redox active metal element according to any of the above embodiments, the method comprising the steps of:
s1, will have M 1 、M 2 Fully mixing the element compound and a lithium source to obtain a precursor;
s2, fully mixing the precursor with molten salt, sintering at high temperature, and cooling to obtain the lithium ion battery anode active material;
wherein, the high-temperature sintering specifically comprises the following steps: firstly, the temperature is raised to 300-600 ℃ for presintering, and then the temperature is raised to 900-1200 ℃ for sintering.
In some embodiments, the ratio of the amounts of substance of the molten salt and the precursor is 1 to 10:1.
in some embodiments, the molten salt is NaCl, KCl, na 2 SO 4 、K 2 SO 4 、 NaNO 3 、KNO 3 At least one of (1).
In some embodiments, the lithium source is Li 2 CO 3 、LiOH、Li 2 At least one of O.
In some embodiments, said M 1 、M 2 Including but not limited to compounds containing only M 1 Elemental compounds, containing only M 2 A compound of the element containing M 1 And M 2 Compounds of elements, specifically including but not limited to M 1 、M 2 At least one of carbonate, nitrate, chloride and oxide; more specifically, including but not limited to M 1 At least one of carbonate, nitrate, chloride and oxide of the element; m 2 At least one of carbonate, nitrate, chloride and oxide of the element; simultaneously contain M 1 、M 2 And the like.
In some embodiments, the pre-sintering time is 2 to 6 hours; the sintering time is 6-24 h.
In some embodiments, the temperature is raised to the pre-sintering temperature at a rate of 3 to 5 ℃/min, and after the pre-sintering is completed, the temperature is raised to the sintering temperature at a rate of 3 to 5 ℃/min.
In some embodiments, after sintering is complete, the furnace is cooled to room temperature.
In some embodiments, after cooling, the method further comprises the steps of: and washing, separating and drying the obtained product to obtain the lithium ion battery anode active material.
The invention also aims to provide a positive pole piece, which comprises the positive active material of the lithium ion battery.
The fourth purpose of the present invention is to provide a lithium ion battery, which includes the above-mentioned positive electrode sheet.
Compared with the prior art, the invention has the following beneficial effects:
the lithium ion metal oxide prepared by combining low-valence metal ions with multi-electron redox activity and high-valence metal ions without redox activity is used as the lithium ion battery positive electrode active material, wherein the low-valence metal ions with multi-electron transfer activity are used as carriers for electron storage and release, multi-electron transfer can be realized in the charging and discharging process, nearly double capacity output under the condition of the same active element content is ensured, the high-valence redox inert metal ions and the low-valence metal can form a stable space three-dimensional structure, and the space group of crystals is Fm-3m, so that the lithium ion battery positive electrode active material has higher stability in the using process, and the lithium ion battery positive electrode active material has excellent cycle stability while having high capacity output.
The invention breaks through the composition design limitation of the traditional lithium ion battery anode active material, and provides a novel high-capacity lithium ion battery anode active material which has high specific capacity and energy density, excellent cycle performance, can be used in the fields of 3C products, electric automobiles and the like, and has good commercial application prospect.
According to the preparation method provided by the invention, the low-melting-point molten salt is used as a reaction medium, a liquid-phase reaction environment is formed in the high-temperature treatment process, and a part of dissolved reactants can be rapidly transferred in the liquid-phase reaction environment, so that the reaction speed is greatly increased, the reaction temperature is reduced, and the controllable growth of crystal nuclei can be realized by regulating the type-to-mass ratio of the molten salt.
In addition, the preparation method can prepare the spherical single crystal metal oxide and effectively avoid particle agglomeration, so that the particle size of the obtained lithium ion battery anode active material is 1-5 mu m, and the grain size is uniform. Compared with the traditional solid phase reaction synthesis method, the molten salt is assisted to provide a liquid environment for multiphase solid phase reaction, so that the grain boundary spreading growth is blocked, the single crystal appearance is modified, the grain size is reduced and homogenized, and the subsequent grinding treatment is avoided. In addition, the fused salt can isolate air, and avoid the oxidation of low-valence active elements into high-valence state by air in the calcining process.
Drawings
FIG. 1 is a process flow for preparing a lithium ion battery positive active material of the present invention;
FIG. 2 shows Li in example 1 1.2 Co 0.4 Nb 0.4 O 2 XRD pattern of (a);
FIG. 3 shows Li in example 1 1.2 Co 0.4 Nb 0.4 O 2 SEM picture of (1);
FIG. 4 shows Li in example 1 1.2 Co 0.4 Nb 0.4 O 2 The charge-discharge curve chart of (1);
FIG. 5 shows Li in example 1 1.2 Co 0.4 Nb 0.4 O 2 A cycle performance map of (a);
FIG. 6 shows Li in example 2 1.2 Ni 0.4 Nb 0.4 O 2 XRD pattern of (a);
FIG. 7 shows Li in example 2 1.2 Ni 0.4 Nb 0.4 O 2 SEM picture of (1);
FIG. 8 shows Li in example 2 1.2 Ni 0.4 Nb 0.4 O 2 The charge-discharge curve chart of (1);
FIG. 9 shows Li in example 2 1.2 Ni 0.4 Nb 0.4 O 2 A cycle performance map of (a);
FIG. 10 is LiCoO in comparative example 1 2 SEM picture of (g);
FIG. 11 is LiCoO in comparative example 1 2 XRD pattern of (a);
FIG. 12 is LiCoO in comparative example 1 2 The charge-discharge curve of (1.5-4.4V);
FIG. 13 is LiCoO in comparative example 1 2 Cycle performance plot (1.5-4.4V);
FIG. 14 is LiCoO in comparative example 1 2 The charge-discharge curve of (1.5-4.3V);
FIG. 15 is LiCoO in comparative example 1 2 Cycle performance diagram (1.5-4.3V).
Detailed Description
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Example 1
The embodiment provides a lithium ion battery anode active material based on a low-valence multi-electron transfer redox active metal element, and the chemical formula of the lithium ion battery anode active material is Li 1.2 Co 2+ 0.4 Nb 5+ 0.4 O 2 The preparation method of the lithium ion battery positive electrode active material is shown in figure 1 and comprises the following steps:
s1, respectively weighing Li according to stoichiometric ratio requirements 2 CO 3 、CoCO 3 、Nb 2 O 5 Mixing to obtain a precursor, wherein Li 2 CO 3 、CoCO 3 Respectively excessive by 10 percent and 5 percent to prevent loss in the high-temperature sintering process; uniformly mixing the precursor by adopting a ball milling method to obtain precursor powder;
s2, weighing the precursor powder, adding the precursor powder and Li 2 CO 3 KCl molten salt with the molar ratio of 1:1 is uniformly mixed; then placing the mixture into a tube furnace, and sintering the mixture at high temperature under the protection of argon atmosphere; wherein, the high-temperature sintering is carried out in two steps, the first step is carried out with the presintering temperature of 600 ℃ and the presintering time of 3h; the second step sintering temperature is 1000 ℃, and the sintering time is 6h; the heating rates of the two-step sintering are controlled at 3 ℃/min; the temperature reduction process adopts furnace cooling;
s3, washing the obtained product distilled water, performing suction filtration and separation, then washing with distilled water and ethanol for 3 times respectively, and performing vacuum drying for 6 hours at 80 ℃ to obtain Li 1.2 Co 2+ 0.4 Nb 5+ 0.4 O 2 A positive electrode active material for lithium ion batteries.
The XRD spectrum of the lithium ion battery anode active material obtained in the embodiment is shown in figure 2, and the XRD spectrum shows that the lithium ion battery anode active material is in a salt rock structure, and the space point group is Fm-3m; the SEM image is shown in figure 3, and the prepared lithium ion battery anode active material is spherical, and the particle size is distributed in the range of 1-5 μm.
Li prepared as described above 1.2 Co 2+ 0.4 Nb 5+ 0.4 O 2 The positive pole piece is made of the positive active material of the lithium ion battery, and the specific mode is as follows: li to be prepared 1.2 Co 2+ 0.4 Nb 5+ 0.4 O 2 Mixing the powder with acetylene black and polyvinylidene fluoride (PVDF, adhesive) according to the mass ratio of 70; and then coating the slurry on an aluminum foil current collector, carrying out vacuum drying at 120 ℃ for 8h, and transferring to an Ar atmosphere glove box for later use.
Assembling a half cell in an Ar atmosphere glove box, taking metal lithium as a counter electrode and LiPF 6 Ethylene carbonate (EC: DMC:DEC = 1). A charge-discharge test was carried out at a current density of C/10 (20 mA/g) using a constant current charge-discharge mode, with a charge cut-off voltage set at 4.4V and a discharge cut-off voltage set at 1.5V.
The electrochemical performance test results of the lithium ion battery cathode active material prepared in this example are shown in fig. 4 and 5.
Example 2
The embodiment provides a lithium ion battery anode active material based on a low-valence multi-electron transfer redox active metal element, which has a chemical formula of Li 1.2 Ni 2+ 0.4 Nb 5+ 0.4 O 2 The preparation method of the lithium ion battery positive electrode active material is shown in figure 1 and comprises the following steps:
s1, respectively weighing Li according to stoichiometric ratio requirements 2 CO 3 、NiCO 3 、Nb 2 O 5 Mixing to obtain a precursor, wherein Li 2 CO 3 、NiCO 3 Respectively excessive by 10 percent and 5 percent to prevent loss in the high-temperature sintering process; uniformly mixing the precursor by adopting a ball milling method to obtain precursor powder;
s2, weighing the precursor powder, adding the precursor powder and Li 2 CO 3 KCl molten salt with the molar ratio of 1:1 is uniformly mixed; then placing the mixture into a tube furnace, and sintering the mixture at high temperature under the protection of argon atmosphere; wherein, the high-temperature sintering is carried out in two steps, the first step is carried out with the presintering temperature of 600 ℃ and the presintering time of 3h; the second step sintering temperature is 1000 ℃, and the sintering time is 6h; the heating rates of the two-step sintering are controlled at 3 ℃/min; the temperature reduction process adopts furnace cooling;
s3, washing the obtained product with distilled water, performing suction filtration and separation, then washing with distilled water and ethanol for 3 times respectively, and performing vacuum drying at 80 ℃ for 6 hours to obtain Li 1.2 Ni 2+ 0.4 Nb 5+ 0.4 O 2 A positive electrode active material for a lithium ion battery. The XRD spectrum of the lithium ion battery positive active material of this example is shown in fig. 6, and the SEM image is shown in fig. 7.
This embodiment will be describedPrepared Li 1.2 Ni 2+ 0.4 Nb 5+ 0.4 O 2 The positive pole piece is made of the positive active material of the lithium ion battery and the lithium ion half battery is assembled. A constant current charge/discharge mode was used to conduct a charge/discharge test at a current density of C/10 (20 mA/g), with a charge cut-off voltage of 4.3V and a discharge cut-off voltage of 1.5V.
The results of the electrochemical performance test of the lithium ion battery cathode active material prepared in this example are shown in fig. 8 and 9.
Comparative example 1
The comparative example provides LiCo which is the cathode active material of the traditional lithium ion battery 3+ O 2 The preparation method comprises the following steps: respectively weighing Li according to the stoichiometric ratio requirement 2 CO 3 、CoCO 3 Wherein Li 2 CO 3 、CoCO 3 Respectively excessive by 10 percent and 5 percent to prevent loss in the high-temperature sintering process; uniformly mixing the precursors by adopting a ball milling method to obtain precursor powder; then heating to 1000 ℃ at the heating rate of 2 ℃/min under the pure oxygen atmosphere, preserving the heat for 12 hours, and then cooling along with the furnace to obtain the LiCo serving as the lithium ion battery anode active material 3+ O 2 . The obtained LiCo serving as the positive electrode active material of the lithium ion battery 3+ O 2 XRD patterns of the resulting LiCo are shown in FIG. 11, which shows 3+ O 2 Is R-3m type structure; the SEM image is shown in FIG. 10.
LiCo to be prepared 3+ O 2 The material is made into a positive pole piece and assembled into a lithium ion half cell. The charge and discharge test was performed at a current density of 20mA/g using the constant current charge and discharge mode, the charge cut-off voltage was set to 4.4V, and the discharge cut-off voltage was set to 1.5V, and the test results are shown in fig. 12 and 13. The charge and discharge test was performed at a current density of 20mA/g using the constant current charge and discharge mode, the charge cut-off voltage was set to 4.3V, and the discharge cut-off voltage was set to 1.5V, and the test results are shown in fig. 14 and 15.
Comparing fig. 3, fig. 7 and fig. 10, the molten salt assisted solid phase reverse phase can modify the morphology of the precursor and obstruct the grain boundary propagation growth in the high temperature reaction process, so as to obtain a spherical-like single crystal with uniform morphology, the grain size is 1-3 microns, and the grain size distribution of the material synthesized by the solid phase method is wider after grinding, which shows that the molten salt method can effectively homogenize the grain size.
Comparing fig. 4 and 12, the oxidation active element Co based on the lower valence multiple electron transfer at the charge cut-off voltage of 4.4V 2+ Li of (2) 1.2 Co 2+ 0.4 Nb 5+ 0.4 O 2 The specific discharge capacity of the first ring is 210.8 mAh/g, which is higher than that of the traditional LiCoO 2 181.1mAh/g. Comparing FIG. 5 with FIG. 13, li 1.2 Co 2+ 0.4 Nb 5+ 0.4 O 2 The 30-turn specific capacity retention rate reaches 87.9 percent, which is far higher than that of the traditional LiCoO 2 The 30-cycle specific capacity retention rate is 77.7%.
Comparing fig. 8 and 14, fig. 9 and 15, the charge cut-off voltage was set to 4.3V, and Ni, an active element, was oxidized based on multiple electron transfer in the case where the initial specific capacity was not much different 2+ Li of (2) 1.2 Ni 2+ 0.4 Nb 5+ 0.4 O 2 The 30-ring cyclic specific capacity retention rate is 89.2 percent, which is much higher than that of the traditional LiCoO 2 The 30-turn cyclic specific capacity retention rate is 79.8 percent.
The results show that the lithium ion battery cathode active material based on the low-valence multi-electron transfer redox active metal element provided by the invention is applied to a secondary battery, and has ultrahigh capacity and good cycle performance.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The lithium ion battery positive electrode active material based on the low-valence multi-electron transfer redox active metal element is characterized in that the structural general formula of the lithium ion battery positive electrode active material is as follows: li x (M 1 M 2 ) 2-x O 2 Wherein M is 1 A metal element having a multiple electron redox activity which is in a low valence state; m 2 The lithium ion battery anode active material is a high-valence oxidation-reduction inert metal element, x is more than 0 and less than 2, the crystal structure of the lithium ion battery anode active material is a rock salt structure, the space point group is Fm-3m, and the total number of the charges of anions and cations of the lithium ion battery anode active material is balanced.
2. The lithium ion battery positive electrode active material based on a low-valence multiple electron transfer redox active metal element according to claim 1, characterized in that 1 ≦ x < 1.5.
3. The lithium ion battery positive electrode active material based on a low valence multiple electron transfer redox active metal element according to claim 1, wherein the M is 1 Is Co 2+ 、Mn 2+ 、Ni 2+ 、Cr 3+ 、V 3+ 、Mo 3+ 、Fe 2+ At least one of; the M is 2 Is Ti 4+ 、Zr 4+ 、Mn 4+ 、Nb 5+ 、Ta 5+ 、W 6+ 、Mo 6+ At least one of (a).
4. The lithium ion battery positive electrode active material based on a low-valence multiple electron transfer redox active metal element according to claim 1, wherein M is 1 Is Co 2+ 、Mn 2+ 、Ni 2+ 、Cr 3+ 、V 3+ 、Mo 3+ 、Fe 2+ One of (1), M 2 Is Ti 4+ 、Zr 4+ 、Mn 4+ 、Nb 5+ 、Ta 5+ 、W 6+ 、Mo 6+ And M is one of 1 And M 2 Are different elements.
5. The method for preparing a positive active material for a lithium ion battery according to any one of claims 1 to 4, comprising the steps of:
s1, will have M 1 、M 2 Fully mixing the element compound with a lithium source to obtain a precursor;
s2, fully mixing the precursor with molten salt, sintering at high temperature, and cooling to obtain the lithium ion battery anode active material;
wherein, the high-temperature sintering specifically comprises the following steps: firstly, the temperature is raised to 300-600 ℃ for presintering, and then the temperature is raised to 900-1200 ℃ for sintering.
6. The method for producing a positive electrode active material for a lithium ion battery according to claim 5, wherein the ratio of the amounts of the molten salt and the precursor substance is 1 to 10:1.
7. the method for preparing the positive active material of the lithium ion battery according to claim 5, wherein the molten salt is NaCl, KCl, na 2 SO 4 、K 2 SO 4 、NaNO 3 、KNO 3 At least one of (1).
8. The method for preparing the positive electrode active material of the lithium ion battery according to claim 5, wherein the temperature is raised to the pre-sintering temperature at a rate of 3-5 ℃/min, and after the pre-sintering is finished, the temperature is raised to the sintering temperature at a rate of 3-5 ℃/min; and/or the presintering time is 2-6 h; the sintering time is 6-24 h.
9. The positive pole piece is characterized by comprising the lithium ion battery positive active material in any one of claims 1 to 4 or the lithium ion battery positive active material prepared by the preparation method in any one of claims 5 to 8.
10. An electrochemical energy storage device comprising the positive electrode sheet of claim 9.
CN202210978353.3A 2022-08-16 2022-08-16 Lithium ion battery positive electrode active material based on low-valence multi-electron transfer redox active metal element and preparation method and application thereof Pending CN115148989A (en)

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CN202210978353.3A Pending CN115148989A (en) 2022-08-16 2022-08-16 Lithium ion battery positive electrode active material based on low-valence multi-electron transfer redox active metal element and preparation method and application thereof

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