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Silicon-base cathode material for lithium ion battery and preparation method of silicon-base cathode material

A silicon-based negative electrode material, lithium-ion battery technology, applied in battery electrodes, electrolyte battery manufacturing, secondary batteries, etc., can solve the problems of serious volume expansion effect, decreased battery cycle stability, high volume expansion rate, etc., and achieve excellent structure Stability, improved stability, high capacity effect

Inactive Publication Date: 2017-05-24
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the volume expansion rate of silicon-based materials is higher than 300% under the condition of high-level deintercalation of lithium, and the volume expansion effect is serious, resulting in a significant decrease in the cycle stability of the battery.

Method used

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  • Silicon-base cathode material for lithium ion battery and preparation method of silicon-base cathode material
  • Silicon-base cathode material for lithium ion battery and preparation method of silicon-base cathode material
  • Silicon-base cathode material for lithium ion battery and preparation method of silicon-base cathode material

Examples

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Effect test

Embodiment 1

[0038] A silicon-based negative electrode material for a lithium ion battery, the preparation steps of which are as follows:

[0039] 1) Mix 0.1g of nano-silicon powder (100-120nm in particle size) with 90mL of concentrated hydrochloric acid with a concentration of 37wt%, and magnetically stir it at room temperature for 1h, then suction filter and wash until the filtrate is neutral and the particles The zeta potential of the surface is negative, and the surface-treated nano-silicon powder is obtained;

[0040]2) Add 0.1211g of tris to a beaker containing 100mL of deionized water to prepare a Tris solution, add 0.2g of dopamine monomer to the obtained Tris solution under nitrogen, and stir fully to obtain dopamine Solution, test the pH value of the solution with pH test paper, and adjust the pH value of the solution to 8.5 with 37wt% hydrochloric acid;

[0041] 3) Pour the dopamine mixed solution obtained in step 2) into the constant pressure titration funnel quickly, isolate ...

Embodiment 2

[0051] A method similar to that of Example 1 is used to prepare silicon-based negative electrode materials for lithium-ion batteries. The difference is that step 1) processes the nano silicon powder with concentrated hydrochloric acid for 0.5h, and step 2) Tris solution is made of 0.6g trimethylol It is prepared by mixing methylaminomethane with 100mL deionized water.

[0052] After testing, the performance of the silicon-based negative electrode material prepared in this example is close to that of the silicon-based negative electrode material obtained in Example 1.

Embodiment 3

[0054] A method similar to that of Example 1 was used to prepare a silicon-based negative electrode material for lithium-ion batteries, except that the volume of concentrated hydrochloric acid used in step 1) was 60 mL.

[0055] The silicon-based negative electrode powder obtained above is prepared as a lithium-ion battery, and the specific steps are as follows:

[0056] a) Dissolve CMC with deionized water first, wherein CMC is 3.5 mg, it is advisable to add deionized water to make the solution reach a suitable viscosity, and stir magnetically for 10 hours until a homogeneous solution is obtained;

[0057] b) 35 mg of the silicon-based active material prepared in this embodiment and 5.25 mg of acetylene black were mixed and ground for half an hour, and poured into the homogeneous solution obtained in the previous step, so that the mass ratio of the silicon-based negative electrode material, acetylene black and CMC was: 80:12:8, add 3 drops of 2.5wt% Tween20 solution dropwise,...

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Abstract

The invention relates to a silicon-base cathode material for a lithium ion battery and a preparation method of the silicon-base cathode material. The preparation method of the silicon-base cathode material comprises the steps that 1) nano silicon powder and hydrochloric acid are mixed, stirred at a room temperature, and then subjected to suction filtration to obtain surface-treated nano silicon powder; 2) a Tris solution is prepared; a dopamine monomer is added to the obtained Tris solution under a nitrogen supply condition; and sufficient stirring is performed to obtain a dopamine solution; and 3) the surface-treated nano silicon powder and the dopamine solution are mixed and sufficiently stirred under a vacuum condition; and then a polymerization reaction is performed in atmosphere to obtain the silicon-base cathode material. According to the method, the nano silicon powder is treated with concentrated hydrochloric acid, a silica oxidation layer is introduced on the surface of the nano silicon powder, and the mechanical strength of the oxidation layer is high, so that a buffer effect is exerted on expansion of the silicon powder. In addition, the silicon powder coating more complete polydopamine is obtained after hydrochloric acid treatment, and CMC (carboxy methylated cellulose) serving as a binding agent and the silicon-base cathode material are used cooperatively, so that the obtained lithium ion battery has better cycle efficiency and initial efficiency.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a silicon-based negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] With the miniaturization, high-energy, and portable development of electronic appliances, the development of large-scale energy storage equipment, space technology, and the research and development of electric vehicles, people have higher and higher requirements for the performance of lithium-ion batteries, and the performance of lithium-ion batteries such as The improvement of capacity, cycle performance and rate performance mainly depends on the improvement of energy density and cycle life of lithium intercalation electrode materials. At present, the theoretical lithium storage capacity of graphite-based carbon-based anode materials widely used in lithium-ion batteries is low, and its maximum theoretical capacity is 372m...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/36H01M4/60H01M4/62H01M10/0525H01M10/058
CPCH01M4/366H01M4/386H01M4/602H01M4/621H01M10/0525H01M10/058Y02E60/10Y02P70/50
Inventor 王雅东张勇郭彬林吴静李珊珊张悦
Owner WUHAN UNIV OF TECH
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