Scalable synthesis of micrometer-sized porous silicon/carbon composites for high-stability lithium-ion battery anodes

Abstract

Although silicon is considered as one of the most promising anode materials, challenges related to the huge volume expansion, low conductivity, as well as tedious synthesis process hinder the practical applications. Herein, a micrometer-sized porous silicon/carbon composite (M-pSi@C) is synthesized via a spray drying process and magnesiothermic reduction method. The spherical M-pSi@C composite exhibits high porosity with rich interconnected channels under the protecting carbon shell, which can not only alleviate the volume expansion but also improve the electrode conductivity. The M-pSi@C electrode has demonstrated excellent electrochemical stability and rate performance, delivering a reversible capacity of 1702 mAh g−1 after 250 cycles at 1 A/g, and a high capacity of 1002 mAh g−1 after 500 cycles at 2 A/g with a capacity retention of 95%. This scalable preparation of micrometer-sized Si/C anode offers great potentials for next-generation lithium ion batteries.