High-first-effect silicon-based negative electrode material and preparation method thereof

A silicon-based negative electrode material, first-effect technology, applied in negative electrodes, battery electrodes, active material electrodes, etc., can solve the problems of reducing the first Coulomb efficiency, increasing the application cost of lithium ion supply end materials, etc., to improve cycle stability, Reduce build time and cost, and improve the effectiveness of constructing buffer layers

Inactive Publication Date: 2020-05-08
苏州宇豪纳米材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the formation of this buffer layer also consumes a large amount of lithium ions, which leads to a decrease in the first coulombic efficiency, which

Method used

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  • High-first-effect silicon-based negative electrode material and preparation method thereof
  • High-first-effect silicon-based negative electrode material and preparation method thereof
  • High-first-effect silicon-based negative electrode material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0036] (1) Put 0.3gliOH into an agate vacuum tank, add 10ml of absolute ethanol, dissolve it, then add 5g of 5um SiO, then add 25g of zirconium balls, vacuumize and fill with hydrogen-argon mixed gas; perform high-energy ball milling and upper ball milling for 30min , the speed is 500r / min;

[0037] (2) transfer the above-mentioned material through ball milling to a quartz crucible ( figure 1 The indicated SiO to be reacted) was vacuum-dried and placed in a rotary furnace. Under the protection of Ar, it was raised to 800°C at 5°C / min and then kept for 10min to produce nano-silicon crystal grains for disproportionation reaction ( figure 1 Schematic "disproportionation"); then rise to 900°C at 5°C / min, pass the organic carbon source isopentane into the rotary furnace under the protection gas, adjust the air flow to 150ml / min, and pyrolyze at high temperature for 30min ( figure 1 Schematic "coating"); After the reaction, the protective gas was changed to room temperature;

[0...

Embodiment 2

[0043] (1) Put 0.5gCa(OH)2 into an agate vacuum tank, add 10ml of absolute ethanol, dissolve and then add 5g5um of SiO, then add 25g of zirconium balls, vacuumize and fill with hydrogen-argon mixed gas; And upper ball milling for 30min, the speed is 500r / min;

[0044] (2) Transfer the ball-milled materials to a quartz crucible, put them into a rotary furnace after vacuum drying, raise them to 750°C at 5°C / min under the protection of Ar, and then keep them warm for 30min to produce nano-silicon grains by disproportionation reaction ; Then rise to 800°C at 5°C / min, pass the organic carbon source p-xylene into the rotary furnace under the protection gas, adjust the gas flow to 200ml / min, and pyrolyze at high temperature for 30min; The protective gas is lowered to room temperature;

[0045] (3) Put the carbon-coated material into a beaker, add 50ml of 1M HCl, stir and wash for 10min, wash with deionized water until neutral, and vacuum dry to obtain the SiOx / C negative electrode m...

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Abstract

The invention relates to a high-first-effect silicon-based negative electrode material and a preparation method thereof. The preparation method comprises: firstly, ball-milling, mixing and drying rawmaterials SiO and hydroxide according to a certain ratio; putting the dried mixed material into a quartz crucible, transferring into a rotary furnace, heating and carrying out heat treatment for a certain time; heating to a certain temperature at a certain rate, introducing a carbon source, carrying out carbon coating for a certain time, cooling to room temperature, and taking out the material; and pickling the material to be neutral, and drying to obtain the material. The invention discloses a high-first-effect negative electrode material. The weakly alkaline hydroxide is utilized to corrodethe SiO surface at a high temperature to form a Si-SiO-SiO<2> core-shell structure; meanwhile, a layer of inert silicate product is used as a buffer layer, so that on one hand, the consumption of lithium ions caused by SEI film formation in the first charge-discharge process can be reduced, the first effect of the material is improved, andrelatively high first charge-discharge capacity and cyclingstability can be maintained; and on the other hand, the disproportionation reaction of SiO and carbon coating are completed by a one-step method, so that the production time and cost are greatly reduced, and industrialization is easy.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a high-first-efficiency silicon-based negative electrode material and a preparation method thereof. Background technique [0002] With the rapid development of electric vehicles, the demand for energy density of batteries is increasing day by day. Due to its low specific capacity (372mAh / g), the existing graphite anode is difficult to meet the needs of future long-range electric vehicles. Due to its high theoretical specific capacity and low lithium-ion potential (0.1V vs Li / Li+), silicon materials show high application prospects in the field of lithium-ion battery anodes. [0003] However, pure silicon materials have inevitable huge volume expansion and poor cycle stability. Silicon monoxide (SiO) has become a new generation of favored anode materials due to its smaller volume expansion and relatively excellent cycle stability. During the first lithium intercalation proces...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/48H01M4/587H01M4/62H01M10/0525
CPCH01M4/366H01M4/483H01M4/628H01M4/587H01M4/386H01M10/0525H01M2004/027H01M2004/021Y02E60/10
Inventor 李敏柳盼盼
Owner 苏州宇豪纳米材料有限公司
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