Preparation and Electrochemical Performance of Polymer-derived SiCN-graphite Composite as Anode Material for Lithium Ion Batteries

摘要

The composite of silicon carbonitride and graphite (SiCN-graphite) composite was synthesized bypyrolyzing the mixture of polysilylethylenediamine-derived amorphous SiCN and graphite powder at atemperature of 1000 C for 1 h in argon. The as-prepared SiCN-graphite material, which was used asanode active substance in a lithium ion battery, showed excellent electrochemical properties. The-1 SiCN-graphite anode exhibited a high initial specific discharge capacity of 975.6 mAh g and a steady-1 specific discharge capacity of 425.0 mAh g after 30 charge-discharge cycles at a current density of 40-1 mA g . Both of the abovementioned values are higher than that of pure polymer-derived SiCN andcommercial graphite under the same charge-discharge condition. Additionally, the SiCN-graphiteanode showed good high charge-discharge rate capability, which met the standard of commercialanode materials. It is considered that the less voids and cracks at the interface of the SiCN-graphiteparticles benefit the electron transfer, resulting in the improvements of the capacity and cycle stability.