Porous silicon and Li-ion batteries

Abstract

Research for advanced Li-ion batteries (LIBs) has been following the direction toward higher energy and power densities. As an anode active material for LIBs, Si has a maximum theoretical capacity far greater than that of the currently commercial graphite anode. However, Si lithiation/de-lithiation is accompanied by large volume expansion/contraction, leading to mechanical instability and hence fast capacity fading. Significant advancement in overcoming this problem has been demonstrated by adopting nanostructured porous Si anode materials, which contain "preset" voids to accommodate volume expansion of the Si particles so that the dimensional variations of the entire electrode layer can be mitigated. This chapter reviews reports of porous Si anode materials synthesized by different methods, including etching, magnesiothermic reaction, templating, and electro-spraying, and the electrochemical performance of the resulting Si anode materials.