The robust carbon shell to improve stability of porous Si anodes for high-performance lithium-ion batteries

Abstract

Abstract Silicon (Si) anode with high theoretical capacity can meet the requirements of high energy density. However, Si anodes suffer from considerable volume expansion and low electron conductivity, resulting in low rate performance and poor cycle stability for Lithium-ion batteries (LIBs). Herein, the carbon coating porous Si (P-Si@C) materials are obtained via decomposition of C2H2 deposition on the surface of porous interconnected Si nanoparticles. Due to the porous structure mitigating Si expansion and the highly robust carbon shell enhancing overall electrical conductivity to improve Li+ diffusivity and ultra-high electron conductivity in Si electrodes. Therefore, the P-Si@C electrodes deliver a high initial Coulombic efficiency (defined as ICE= 83.2%) and long life (high discharge capacity of 1424\xa0mA\xa0h/g) at 4\xa0A/g after 600 cycles. As a result, the assembled P-Si@C // LiFePO4 full cell shows a high discharge capacity of 85\xa0mA\xa0h/g at 1\xa0C after 200 cycles, corresponding to high retention 88.5%.