High capacity silicon nitride-based composite anodes for lithium ion batteries
By de Guzman, Rhet C.; Yang, Jinho; Ming-Cheng Cheng, Mark; Salley, Steven O. & Ng, K. Y. Simon
Published in J. Mater. Chem. A
The Royal Society of Chemistry
2014
Abstract
A new composite material comprised of Si nitride (SiNx) derived from Si nanoparticles (SiNPs) via a vacuum CVD approach within a graphene matrix was synthesized as a potential Li ion battery (LIB) anode material. The deposition technique generated an external composition of Si3N4 and SiN0.73 on the SiNP, with the overall N-levels increasing with deposition time. The SiNx electrochemical reaction can be attributed to a two-stage reversible mechanism: first the SiNx phase was converted to a matrix of Li3N with embedded nano Si, and then the Si content participates in the high capacity alloying/dealloying reactions. Galvanostatic cycling of the composite (50% Si w/w) using 500 mA g-1 displayed exceptionally stable capacity around 1400 mA h g-1 attributed to the improved stress management and conductivity of the Li3N matrix. SiNx is demonstrated to be a compelling anode for LIBs, and with further development and optimization this might become the leading contender for the high capacity anode to possibly succeed current graphitic electrodes.