A Low-Cost Nano/Micro Structured-Silicon-MWCNTs from Nano-Silica for Lithium Storage

Abstract

Despite the fact that silicon material can be synthesized from various sources, deriving them from silica resources is of strategic significance for the industrial processing. Here a low-cost nano/micro structure of Si-CNT was derived from nano-SiO2 and multiwall carbon nanotubes (MWCNTs) with simple methods. By employing table salt (NaCl) as a heat scavenger for the magnesiothermic reduction, the nano/micro structure of the material was remained effective. Comparing to ball milling, a combination of SiO2, MWCNTs and NaCl by spray drying achieved the long cycle life for Si-CNT composite. This material presented a stable capacity above 968.1mAh g-1 with excellent capacity retention of 85.4% at the 150th cycle versus the 2nd one. The Si nanoparticles, very small particle size in 10-20nm, homogenously dispersed in electronically conductive network of MWCNTS, which accommodate the volume change of Si and reinforce highly conductivity of the Si-CNT composite during repeated cycles. Combined with its low-cost and up-scaling technologies, Si-CNT composite is a promising anode material in rechargeable lithium batteries with high electrochemical performance.