Etched Graphite with Internally Grown Si Nanowires from Pores as an Anode for High Density Li-Ion Batteries

Abstract

A novel architecture consisting of Si nanowires internally grown from porous graphite is synthesized by etching of graphite with a lamellar structure via a VLS (vapor-liquid-solid) process. This strategy gives the high electrode density of 1.5 g/cm3, which is comparable with practical anode of the Li-ion battery. Our product demonstrates a high volumetric capacity density of 1363 mAh/cm3 with 91% Coulombic efficiency and high rate capability of 568 mAh/cm3 even at a 5C rate. This good electrochemical performance allows porous graphite to offer free space to accommodate the volume change of Si nanowires during cycling and the electron transport to efficiently be improved between active materials.