Embedding silicon in biomass-derived porous carbon framework as high-performance anode of lithium-ion batteries

Abstract

Silicon (Si) is regarded as a promising anode material for lithium-ion batteries because of its ultrahigh theoretical specific capacity, appropriate potential, and abundant resources. However, its inherent insulation and large volume changes lead to inferior electrochemical activity and unsatisfactory cycling stability, thus limiting its practical applications. In this study, a grape stem-derived porous carbon framework (PCF) with slender through-holes in the interior and a large number of micropores on the carbon walls was prepared via a facile approach and employed as the Si matrix. The continuous through-holes and well-distributed oxygen-containing functional groups of the PCF provided the Si nanoparticles with sufficient space to accommodate volumetric expansion and abundant active sites for adsorption. Additionally, the porous structure and high conductivity of the PCF facilitated electrolyte penetration and electron transfer. Therefore, the PCF/Si composite exhibited a decent discharge capacity (1006 mA h g−1 at 0.2 A g−1) and robust cycling stability (891 mAh g−1 remaining after 400 cycles).