A method for simultaneous regulation of surface structure and chemical composition of layered lithium-rich cathode materials

A lithium-rich cathode material and surface structure technology, applied in structural parts, electrochemical generators, battery electrodes, etc., can solve the problems of excellent comprehensive electrochemical performance, inability to obtain, etc., achieve excellent electrochemical performance, good application prospects, Effect of stabilizing cycle life

Active Publication Date: 2020-12-15
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Common surface modification methods, such as surface coating, surface doping, acid treatment, etc., can effectively improve the performance of materials, but often can only change one aspect alone, so that better comprehensive electrochemical performance cannot be obtained.
How to change the surface structure or chemical composition of materials at the same time is still a huge challenge

Method used

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  • A method for simultaneous regulation of surface structure and chemical composition of layered lithium-rich cathode materials
  • A method for simultaneous regulation of surface structure and chemical composition of layered lithium-rich cathode materials
  • A method for simultaneous regulation of surface structure and chemical composition of layered lithium-rich cathode materials

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] (1) Weigh the spherical Mn obtained by hydrothermal synthesis 0.6 Ni 0.2 co 0.2 CO 3 Put 2.0g of carbonate precursor in a 50mL beaker, measure 30mL of 3.0mol / L ammonia solution into the beaker containing carbonate precursor, stir magnetically for 10min, then wash and filter with distilled water several times , and finally placed in a blast drying oven at 80° C. for 12 hours to obtain a carbonate precursor treated with ammonia water. For comparison, using the same method, change the ammonia water treatment time to 5min, 20min and 40min, respectively to obtain the corresponding carbonate precursor after treatment.

[0028] (2) The carbonate precursors treated with ammonia water obtained in step (1) for 5 min, 10 min, 20 min, and 40 min were respectively calcined at 500° C. for 6 h to obtain oxides.

[0029](3) Mix the oxides obtained in the above steps with lithium carbonate respectively in the ratio of [Li]:[M]=1.42:1 ([Li] is the number of moles of lithium, [M] is t...

Embodiment 2

[0036] (1) Weigh the spherical Mn obtained by hydrothermal synthesis 0.6 Ni 0.2 co 0.2 CO 3 Put 2.0g of the carbonate precursor in a 50mL beaker, measure 30mL of 2.0mol / L ammonium sulfate solution and pour it into the beaker containing the carbonate precursor, stir it magnetically for 20min, and then wash it several times with distilled water, Filter, and finally place in a blast drying oven at 80° C. for 12 hours to obtain the treated carbonate precursor.

[0037] (2) Calcinate the untreated carbonate precursor and the ammonium sulfate solution obtained in step (1) for 20 minutes at 500° C. for 6 hours to obtain the oxide.

[0038] (3) Mix the oxide and lithium carbonate obtained in the above steps uniformly at a ratio of [Li]:[M]=1.42:1, and place them in a muffle furnace for calcination at 750° C. for 12 hours to obtain a lithium-rich cathode material.

[0039] Electrochemical tests show that the lithium-rich cathode material obtained after ammonium sulfate treatment ha...

Embodiment 3

[0041] (1) Weigh the spherical Mn synthesized by co-precipitation method 0.75 Ni 0.25 CO 3 Carbonate precursor 3.0g is placed in a 50mL beaker, and 30mL of 2.0mol / L ammonium carbonate solution is poured into the beaker containing the carbonate precursor, mechanically stirred for 30min, and then washed several times with distilled water, Filter, and finally place in a blast drying oven at 80° C. for 12 hours to obtain an ammonia-treated carbonate precursor.

[0042] (2) The untreated carbonate precursor treated with the ammonium carbonate solution obtained in step (1) for 30 minutes was calcined at 400° C. for 8 hours to obtain an oxide precursor.

[0043] (3) Mix the oxide precursor and lithium hydroxide obtained in the above steps uniformly at a ratio of [Li]:[M]=1.55:1, and place them in a muffle furnace for calcination at 700°C for 24 hours to obtain a lithium-rich positive electrode Material.

[0044] Electrochemical tests show that the lithium-rich cathode material ob...

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Abstract

The invention discloses a synchronous control method for a surface structure and a chemical composition of a layered lithium-rich cathode material, wherein the cathode material has the general formulaof xLi2MnO3.(1-x)LiMO2 or Li1+x[M]1-xO2, and M is one or a plurality of Mn, Co, and Ni. The method comprises the steps of: 1) placing a carbonate precursor in a treating agent solution for surface treatment; and 2) burning the treated carbonate precursor into an oxide for uniform mixing with the lithium source compound, and obtaining a surface-modified layered lithium-rich cathode material by high temperature calcination. The main body of the material is of a layered structure with a spinel phase on the surface, a transitional mixed phase is provided between the layered structure and the spinel phase, and the chemical composition of the surface is different from that of the host. The invention has simple and easy operation, and is capable of imparting excellent electrochemical performances such as rapid lithium ion diffusion channel, stable cycle life and weak voltage decay of the positive electrode material.

Description

technical field [0001] The invention relates to a method for synchronous regulation and control of the surface structure and chemical composition of a layered lithium-rich positive electrode material, which belongs to the field of energy materials and electrochemistry. Background technique [0002] Lithium-ion battery has become the most widely developed and applied power system due to its advantages of large specific energy, high working voltage, low self-discharge rate and light weight. However, the current energy density, power characteristics, safety performance and cost issues of lithium-ion batteries still restrict its further development, especially it is difficult to meet the application requirements of high-energy-density power supplies for strategic emerging industries such as electric vehicles. The energy density of lithium-ion batteries mainly depends on the positive electrode material, and improving the specific capacity or working voltage of the positive electr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/505H01M4/525H01M10/0525
CPCH01M4/505H01M4/525H01M10/0525Y02E60/10
Inventor 杨秀康吴炳姜霞王先友舒洪波刘黎高平余睿智
Owner XIANGTAN UNIV
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