Positive electrode active material and preparation method thereof, all-solid lithium battery

A positive electrode active material and a positive electrode technology are applied in the fields of all-solid-state lithium batteries, positive-electrode active materials and their preparation, and can solve the problem of decreasing the ion conductivity of all-solid-state lithium batteries, reducing the reversibility of all-solid-state lithium batteries, and reducing the capacity of all-solid-state lithium batteries. and other problems, to achieve the effect of improving the specific capacity and cycle stability of the battery, improving the cycle stability and specific capacity, and improving the cycle stability

Active Publication Date: 2020-11-20
SOUNDON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] But ferrous sulfide can have following technical problem in carrying out redox reaction process: one, there is volume expansion effect; Two, there is the Li generated in reaction process 2 S is easy to migrate to the negative electrode, leading to the problem of rapid decline in the capacity of the all-solid-state lithium battery, that is, there is a shuttle effect; 3. Li 2 S is an insulator, which will lead to a decrease in the ionic conductivity of the all-solid-state lithium battery; four, Li 2 S does not have electrochemical activity, which will reduce the reversibility of all-solid-state lithium batteries

Method used

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  • Positive electrode active material and preparation method thereof, all-solid lithium battery
  • Positive electrode active material and preparation method thereof, all-solid lithium battery

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preparation example Construction

[0040] According to a second aspect of the present invention, the present invention provides a method for preparing a positive electrode active material, comprising the steps of:

[0041] Mixing nano-ferrous sulfide and carbon-containing high polymer to obtain nano-ferrous sulfide coated with carbon-containing high polymer, and sintering to obtain positive electrode active material;

[0042] Wherein, the positive electrode active material includes nano ferrous sulfide and a carbon layer covering the nano ferrous sulfide.

[0043] The preparation method of the positive electrode material of the all-solid-state lithium battery provided by the invention has simple process, convenient operation, can carry out large-scale industrial production, improves production efficiency, and reduces preparation cost.

[0044] In a preferred embodiment of the present invention, the carbon-containing high polymer includes but not limited to one or more of polyvinylpyrrolidone, polyethylene glyco...

Embodiment 1

[0070] This embodiment provides a positive electrode material for an all-solid-state lithium battery, including nano-ferrous sulfide and a carbon layer coated with nano-ferrous sulfide, which is prepared according to the following steps:

[0071] (1) Place commercialized ferrous sulfide with a particle size of more than 10 microns in a zirconia ball mill tank under the protection of argon, and ball mill it for 32 hours at a speed of 700 rpm to obtain nanometer ferrous sulfide particles with a particle size of 100-500 nm ;

[0072] (2) Dissolve polyvinylpyrrolidone (PVP) in N,N dimethylformamide (DMF) and disperse evenly, then add nano ferrous sulfide particles, stir magnetically for 6 hours, and distill under reduced pressure to remove DMF to obtain PVP coated nano The precursor particle of ferrous sulfide; Wherein, the mass ratio of nano ferrous sulfide and PVP is 95:5;

[0073] (3) The precursor particles were heated at 400° C. for 1 hour, and then sintered at 800° C. for 1...

Embodiment 2

[0075] This embodiment provides a positive electrode active material, including nano-ferrous sulfide and a carbon layer coated with nano-ferrous sulfide. The difference between its preparation method and Example 1 is that in step (1), a 10-micron The above ferrous sulfide is ball milled into nano ferrous sulfide with a particle size of 50-300nm.

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Abstract

The invention provides a positive electrode active material as well as a preparation method thereof, and an all-solid-state lithium battery. The positive electrode active material comprises nano-ferrous sulfide and a carbon layer coating nano-ferrous sulfide. The positive electrode active material provided by the invention, firstly, inhibits the volume expansion of ferrous sulfide during a redox reaction; secondly, the active material suppresses a shuttle effect of Li2S generated during the reaction to migrate to a negative electrode; thirdly, Li2S is an insulator which causes the ionic conductivity of the all-solid-state lithium battery to decrease, however, after coating with the carbon layer, the ionic conductivity of the all-solid-state lithium battery is improved due to the relativelyhigh ionic conductivity of the carbon layer; and fourthly, Li2S has no electrochemical activity, and Li2S is further electrochemically active after nano-ferrous sulfide is coated with the carbon layer, the polarization is reduced, and the reversibility of the battery is enhanced, thereby improving the cycle stability and battery specific capacity of the all-solid-state lithium battery comprisingthe positive electrode active material.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a positive electrode active material, a preparation method thereof, and an all-solid lithium battery. Background technique [0002] Based on LiMO 2 (M=transition metal) lithium-ion batteries with positive electrodes and graphite negative electrodes, the energy density has reached the upper limit at present. [0003] In order to increase the energy density of lithium-ion batteries and meet the needs of electric vehicles and large-scale energy storage, transition metal compounds have received more and more attention as cathode materials. Several types of transition metal compounds such as oxides, sulfides, and fluorides can provide multiple electrons during redox reactions, thereby enabling lithium-ion batteries to have higher capacities. [0004] Among the above-mentioned transition metal compounds, ferrous sulfide (FeS) is due to its low price, environmental friendliness, and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/052
CPCH01M4/366H01M4/5815H01M4/62H01M4/625H01M4/628H01M10/052Y02E60/10
Inventor 刘茜陈渊周美丽倪海芳
Owner SOUNDON NEW ENERGY TECH CO LTD
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