Silicon-carbon composite material with high specific capacity, preparation method of silicon-carbon composite material, lithium ion battery anode material and lithium ion battery

Abstract

The invention discloses a silicon-carbon composite material for a lithium ion battery, a preparation method of the silicon-carbon composite material, and a lithium ion battery anode material and the lithium ion battery, which are prepared from the silicon-carbon composite material. The silicon-carbon composite material comprises a porous carbon matrix material with pores and nano silicon particles composited among the pores of the porous carbon matrix material. The particle diameter of each nano silicon particle in the silicon-carbon composite material is 5-100 nm, wherein the content of nano silicon is 10-90 wt%. The silicon-carbon composite material has a simple manufacturing process and is capable of obviously reducing a volume effect of a silicon-containing active substance in the process of being intercalated and de-intercalated with lithium, improving a diffusion behaviour of lithium in an active material and increasing the specific capacity of the lithium ion battery. The battery anode material prepared from the composite material has a good conductivity property. The prepared lithium ion battery has a good cycling property.

Description

technical field [0001] The invention belongs to the technical field of battery manufacturing, and in particular relates to a high-specific-capacity silicon-carbon composite material and a preparation method thereof, and a lithium-ion battery negative electrode material and a lithium-ion battery containing the silicon-carbon composite material. Background technique [0002] At present, the negative electrodes of commercial lithium-ion batteries use graphitized carbon, such as mesocarbon microspheres MCMB and CMS materials. The volume expansion of these materials is basically below 9% during the lithium intercalation and desorption process, showing high Coulombic efficiency and excellent performance. Cycle stability. However, the theoretical lithium intercalation capacity of graphite is 372mAh / g, which has actually reached 370mAh / g. Therefore, the low theoretical lithium storage capacity of the graphite electrode itself makes it difficult to make breakthroughs. Researchers hav...

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Problems solved by technology

People such as Wu Jishan (Hongfa Xiang, Kai Zhang, Ge Ji, Jim Yang Lee, Changji Zou, Xiaodong Chen, Jishan Wu, CARBON 49 (2011) 1787 1796) have reported that graphene directly mixes synthetic composite anode material with nano silicon powder method, the obtained material shows good cycle performance, and the specific capacity can still maintain 1600mAh / g after 30 cycles, but it still decays slowly

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