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

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 mA h/g) at 4 A/g after 600 cycles. As a result, the assembled P-Si@C // LiFePO4 full cell shows a high discharge capacity of 85 mA h/g at 1 C after 200 cycles, corresponding to high retention 88.5%. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The carbon-coated porous silicon (P-Si@C) materials showed improved performance in lithium-ion batteries, with porous structure mitigating silicon expansion and robust carbon shell enhancing overall electrical conductivity. This led to a high initial Coulombic efficiency and long cycle life, demonstrating potential for high capacity and stability in LIBs.