Preparation method of nanoporous silicon of negative electrode material of lithium battery

Abstract

The invention relates to porous silicon or porous silicon metal and a preparation method thereof. The preparation method comprises the following steps of: 1) putting nanosilicon-based alloy in a vacuum heat treatment furnace, and maintaining the vacuum degree between -0.095-0Mpa; then heating, maintaining the temperature between 600-1300 DEG C for 0.1-10 hours; 2) after easily-volatile alloy elements of the nanosilicon-based alloy volatilize gradually under the vacuum condition, thus obtaining the nanoporous silicon of a negative electrode material of a lithium-ion battery. Compared with the prior art, the preparation method is simple, the prepared nanoporous silicon has the advantages of uniform pore-diameter dispersion, high specific energy, good cyclicity and rate performance, simple reaction process and less time consumption and the like; simultaneously, the preparation method is low in cost and high in preparation efficiency, can better meet the need of industrial production and realizes large-scale production.

Description

technical field [0001] The invention belongs to the technical field of preparation of negative electrode materials of lithium ion batteries, and in particular relates to a preparation method of nanoporous silicon, a negative electrode material of lithium batteries. Background technique [0002] Lithium batteries have become the most promising power system for electric vehicles and battery products due to their advantages such as high specific energy, small self-discharge, environmental protection, and long cycle life. At present, the commonly used negative electrodes for lithium batteries are mainly graphite materials. The theoretical capacity of this type of material is only 372mAh / g, and its low theoretical specific capacity limits the overall improvement of lithium battery performance. Therefore, it is particularly important to develop new high specific energy negative electrode materials. [0003] Metal silicon and lithium can form a silicon-lithium alloy (Li 4.4 Si), a...

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Problems solved by technology

[0009] Aiming at the problems of complex preparation methods, high cost, low efficiency, and low specific energy of the prepared porous silicon negative electrode material in the above-mentioned prior art, one of the purposes of the present invention is to provide a method for preparing nanoporous silicon as a lithium battery negative electrode material

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