Silicon nanoparticles embedded in a porous carbon matrix as a high-performance anode for lithium-ion batteries

Abstract

Silicon-based anodes have recently received increased attention due to their high theoretical capacity. However, the Si-based anodes always suffer from a large volume change during cycling and require expensive and multistep processes to prepare nano-sized Si. In this work, Si nanoparticles are successfully embedded in a carbon matrix by using NaCl particles as a hard template, which were prepared through magnesiothermic reduction of SiO₂ nanoparticles. Besides, NaCl particles also play an important role in absorbing the local heat accumulation generated from magnesiothermic reduction, thus preventing the agglomeration of Si particles and the formation of undesirable SiC. The as-prepared Si@PCM could not only provide fast electron diffusion through carbon networks, but also accommodate the stress–strain caused by the volume change. As a result, the Si@PCM composite demonstrates an excellent electrochemical performance as an anode material for lithium-ion batteries.