Preparation method of porous silicon/graphene composite material

A composite material and graphene technology, applied in the field of lithium-ion batteries, can solve the problems of low capacity and low overall capacity of composite materials, and achieve the effects of high capacity density, stable cycle performance and high Coulombic efficiency

Inactive Publication Date: 2014-08-27
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Chinese Patent Application Publication No. CN103579596A discloses a preparation method of lithium-ion battery negative electrode materials, using rice husk as raw material, and preparing silicon / carbon composite materials through metallothermic reduction. Lower, resulting in a lower overall capacity of the composite (<750mAh / g)

Method used

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Experimental program
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Effect test

Embodiment 1

[0027] The preparation method of this porous silicon / graphene composite material, its specific steps are as follows:

[0028] (1) Firstly pickling, washing, filtering and drying 500g of rice husks to obtain rice husks free of alkali metal oxide impurities, wherein the rice husks include the following mass percentage components: crude fiber 45%, lignin 26%, ash 11.4% %, silicon dioxide 10%; the acid in the pickling process is HCl, its concentration is 5wt%, the pickling time is 10h, and the washing is deionized water until the pH is 6-7;

[0029] (2) Pyrolyzing the rice husk obtained in step (1) with the alkali metal oxide impurities removed at low temperature under anaerobic conditions to obtain pyrolyzed rice husk, wherein the pyrolysis temperature is 600°C, and the pyrolysis time is 0.1h;

[0030] (3) The pyrolyzed rice husk obtained in step (2) was added to the precursor salt solution according to the liquid-solid ratio of 80:1ml / g, and then the high-temperature catalytic c...

Embodiment 2

[0037] The preparation method of this porous silicon / graphene composite material, its specific steps are as follows:

[0038] (1) First, 500g of rice husks were pickled, washed, filtered and dried to obtain rice husks free of alkali metal oxide impurities, wherein the rice husks contained the following mass percentage components: crude fiber 35.5%, lignin 21%, ash 22% %, silicon dioxide 21%; the acid in the pickling process is HNO 3 , the concentration is 40wt%, the pickling time is 1h, and the washing is deionized water until the pH is 6-7;

[0039] (2) Low-temperature pyrolysis of the rice husk obtained in step (1) from which alkali metal oxide impurities have been removed is performed under anaerobic conditions to obtain pyrolyzed rice husk, wherein the pyrolysis temperature is 300° C., and the pyrolysis time is 2 hours;

[0040] (3) The pyrolyzed rice husk obtained in step (2) was added to the precursor salt solution according to the liquid-solid ratio of 20:1ml / g, and th...

Embodiment 3

[0046] The preparation method of this porous silicon / graphene composite material, its specific steps are as follows:

[0047] (1) First, 500g of rice husks were pickled, washed, filtered and dried to obtain rice husks free of alkali metal oxide impurities, wherein the rice husks contained the following mass percentage components: crude fiber 40.3%, lignin 23.5%, ash 16.7% %, silicon dioxide 15.5%; the acid in the pickling process is H 2 SO 4 , the concentration is 20wt%, the pickling time is 9h, and the washing is deionized water until the pH is 6-7;

[0048] (2) Low-temperature pyrolysis of the rice husk obtained in step (1) from which alkali metal oxide impurities have been removed is performed under aerobic conditions to obtain pyrolyzed rice husk, wherein the pyrolysis temperature is 500° C., and the pyrolysis time is 1 h;

[0049] (3) The pyrolyzed rice husk obtained in step (2) was added to the precursor salt solution according to the liquid-solid ratio of 50:1ml / g, an...

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Abstract

The invention relates to a preparation method of a porous silicon/graphene composite material, and belongs to the technical field of lithium ion batteries. The method comprises: firstly, performing acid pickling of rice husks, then performing low-temperature aerobic or anaerobic pyrolysis to obtain pyrolyzed rice husks; dipping the pyrolyzed rice husks in a transition metal salt solution, performing high-temperature catalytic carbonization to obtain catalytically-carbonized rice husks; performing low-temperature oxidation of the catalytically-carbonized rice husks, mixing with reductive metal, performing high-temperature metal thermal reduction under an anaerobic condition, and then performing acid pickling of the reduction product to obtain the porous silicon/graphene composite material. The porous silicon/graphene composite material prepared by the method has the characteristics of large capacity density, good rate capability, high first coulombic efficiency, stable cycle performance, and the like.

Description

technical field [0001] The invention relates to a preparation method of a porous silicon / graphene composite material, belonging to the technical field of lithium ion batteries. Background technique [0002] With the rapid development of the electronics and information industries, mobile communications, digital cameras and portable computers are widely used, and the research and development of electric vehicles is also being carried out extensively and deeply, thus driving the rapid development of lithium-ion batteries, which provide energy for the above-mentioned equipment. develop. Compared with traditional nickel-metal hydride batteries and nickel-cadmium batteries, lithium-ion batteries have the advantages of high energy density, high working voltage, small self-discharge, fast charging and discharging, and good safety performance. They are the fastest growing and brightest market prospects. A secondary battery. [0003] At present, the focus of lithium-ion battery rese...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583H01M4/36
CPCH01M4/364H01M4/38H01M4/583H01M10/0525Y02E60/10
Inventor 刘树和赵淑春
Owner KUNMING UNIV OF SCI & TECH
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