A kind of preparation method of silicon negative electrode material coated with carbon and lithium titanate double layer

A double-layer coating and lithium titanate technology, which is applied to battery electrodes, electrical components, electrochemical generators, etc., can solve problems such as hindering lithium ion intercalation and extraction, affecting battery performance, and low conductivity. The effect of uniformity, large specific capacity and long cycle life

Inactive Publication Date: 2016-01-20
SHANGHAI NAT ENG RES CENT FORNANOTECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Silicon and lithium titanate have the same disadvantages, that is, the conductivity is not high, and it is easy to cause electron enrichment during charging and discharging, which hinders the insertion and extraction of lithium ions, and affects the performance of the battery at high rates.

Method used

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  • A kind of preparation method of silicon negative electrode material coated with carbon and lithium titanate double layer

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Experimental program
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Effect test

Embodiment 1

[0021] The soluble compounds of Li and Ti are compounded according to the mol ratio of Li:Ti=0.84:1, and 25.52g of tetra-n-butyl titanate (analytical pure), 2.33g of lithium carbonate (analytical pure), 20g Add EDTA and 30g of citric acid to 300ml of absolute ethanol, stir evenly with a magnetic heating stirrer to form a sol; then add 0.2g of nano-silica powder, and heat and stir at 80°C until a gel with fully dispersed silicon sources is obtained ;Dried in a blast oven at 240°C to obtain a black and fluffy lithium titanate-coated silicon precursor; then put the precursor into a high-energy ball mill for ball milling for 1~10h, where the mass ratio of balls to materials is 2:1 , to obtain a fine-grained lithium titanate-coated silicon precursor; finally, put the fine-grained precursor into a tube furnace, pass through Ar gas, and calcinate at 750 ° C for 5 hours to obtain the finished carbon and lithium titanate double-layer coating Silicon anode material.

Embodiment 2

[0023] The soluble compounds of Li and Ti are compounded according to the mol ratio of Li:Ti=0.84:1, and 21.31g of tetraisopropyl titanate (analytical pure), 6.43g of lithium acetate (analytical pure), 20g Add EDTA and 40g of citric acid into 300ml of absolute ethanol, and stir evenly with a magnetic heating stirrer to form a sol; then add 0.2g of mesoporous silicon nanoparticles, and heat and stir at 80°C until the silicon source is fully dispersed. Gel; dry in a blast oven at 240°C to obtain a black fluffy lithium titanate-coated silicon precursor; then put the precursor into a high-energy ball mill for 1-10 hours, where the mass ratio of balls to materials is 2 : 1, to obtain a fine-grained lithium titanate-coated silicon precursor; finally put the fine-grained precursor into a tube furnace, and pass through 95%Ar+5%H 2 , and calcined at 750°C for 5h to obtain the finished carbon and lithium titanate double-layer coated silicon negative electrode material.

Embodiment 3

[0025] The soluble compounds of Li and Ti are compounded according to the molar ratio of Li:Ti=0.88:1, and 25.52g of tetra-n-butyl titanate (analytical pure), 4.55g of lithium nitrate (analytical pure), 20g Add EDTA and 60g of citric acid to 300ml of absolute ethanol, stir evenly with a magnetic heating stirrer to form a sol; then add 0.6g of nano-silica powder, and heat and stir at 80°C until a gel with fully dispersed silicon sources is obtained ;Dried in a blast oven at 240°C to obtain a black and fluffy lithium titanate-coated silicon precursor; then put the lithium titanate precursor into a high-energy ball mill for 1-10h, and the mass ratio of the ball to the material is 2:1, to obtain a fine-grained lithium titanate-coated silicon precursor; finally, put the fine-grained precursor into a tube furnace, pass through Ar gas, and calcinate at 750 ° C for 5 hours to obtain the finished carbon, lithium titanate bis layer covering the silicon negative electrode material.

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Abstract

The invention belongs to the secondary lithium ion battery key material technical field, and provides a method for preparing a carbon-lithium titanate double-layer coated silicon negative electrode material. With chelating agents as carbon sources, a soluble Ti compound as a titanium source, a nano silicon source and various lithium compounds as lithium sources, the carbon-lithium titanate double-layer coated silicon negative electrode material is synthesized by a double-chelating-agent sol-gel method. Through combination of advantages of lithium titanate and the silicon material, a prepared lithium ion battery has high specific capacity, excellent cycling stability and quite high consistency, allows the high specific capacity and the high stability to be organically gathered together, and has wide application prospects.

Description

technical field [0001] The invention relates to a preparation method of a battery negative electrode material, in particular to a preparation method of a silicon negative electrode material coated with carbon and lithium titanate double layers. Background technique [0002] In the context of environmental pollution and energy shortage, lithium-ion batteries have become the first consideration for many manufacturers when choosing power because of their clean, pollution-free, high-efficiency and recyclable characteristics. The development of new lithium-ion batteries with larger specific capacity, better cycle performance, faster and safer charge and discharge has also become the goal of many scientific and technological workers. [0003] Silicon has the largest theoretical specific capacity (3572mAh / g) among known negative electrode materials for lithium-ion batteries, and a low delithiation potential (<0.5V) at room temperature, and has become the next-generation high-cap...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/485
CPCH01M4/366H01M4/485H01M4/625H01M10/0525Y02E60/10
Inventor 张春明黄昭王丹吴晓燕严鹏何丹农
Owner SHANGHAI NAT ENG RES CENT FORNANOTECH
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