General Research Institute for Nonferrous Metals

China Automotive Battery Research Institute Co., Ltd.

Juanyu Yang

Shigang Lu

Xiangjun Zhang

Surong Kan

Xingming Wang

Zhefeng Gao

Haiyang Ding

The invention relates to a nano silicon-carbon composite negative material for lithium ion batteries and a preparation method thereof. A porous electrode composed of silica and carbon is taken as a raw material, and a nano silicon-carbon composite material of carbon-loaded nano silicon is formed by a molten salt electrolysis method in a manner of silica in-situ electrochemical reduction. Silicon and carbon of the material are connected by nano silicon carbide, and are metallurgical-grade combination, so that the electrochemical cycle stability of the nano silicon-carbon composite material is improved. The preparation method of the nano silicon-carbon composite material provided by the invention comprises the following steps: compounding a porous block composed of carbon and silica powder with a conductive cathode collector as a cathode; using graphite or an inert anode as an anode, and putting the cathode and anode into CaClelectrolyte or mixed salt melt electrolyte containing CaClto form an electrolytic cell; applying voltage between the cathode and the anode; controlling the electrolytic voltage, the electrolytic current density and the electrolytic quantity, so that silica in the porous block is deoxidized into nano silicon by electrolytic reduction, and the nano silicon-carbon composite material for lithium ion batteries is prepared at the cathode.

Nano silicon-carbon composite material and preparation method thereof

An electrochemical method for producing Si nanopowder, Si nanowires and/or Si nanotubes directly from compound SiX or a mixture containing a silicon compound SiX, the method comprises: providing an electrolysis cell having a cathode, an anode and an electrolyte, using the compound SiX or the mixture containing compound SiX as a cathode and immersing the cathode in an electrolyte comprising a metal compound molten salt, applying a potential between the cathode and the anode in the electrolysis cell, and forming one or more of Si nanopowder, Si nanowires and Si nanotubes on the cathode electrode. The method has advantages of: 1) shorter production processing, 2) inexpensive equipment, 3) convenient operation, 4) reduction of contaminate, 5) easily available feed materials, and 6) easy to achieve continuous production. This is a new field of using electrochemical method for producing one-dimensional Si nano material, and a new method of producing Si nanopowder, Si nanowires and Si nanotubes.

Electrochemical methods for making silicon nanopowder, silicon nanowires and silicon nanotubes

Growing community of inventors

Beijing, China

Juanyu Yang