Stress-Relief Network in Silicon Microparticles and Composite Anodes for Durable High-Energy-Density Batteries

Abstract

Silicon microparticles (SiMPs), which have a high capacity, a high initial Coulombic efficiency, and a low volume-to-surface ratio compared with nanosized materials, are promising anode materials for high-energy-density battery applications. However, SiMPs suffer from inevitable particle pulverization and electrode failure at the early cycle. In this study, we suggest the construction of a porous, stress-relief carbon network on the surface of each SiMP to alleviate particle degradation at the electrode level through a template-free co-reaction of thermal polymer pyrolysis and graphitization. The designed porous graphitic carbon network (pGN) structure features not only considerable electrical conductivity and expansion tolerance but also sturdy SiMP interconnection during cycling. This enables SiMPs to improve battery performance and achieve high Coulombic efficiency and a stable cycle life in fast-charging systems without particle dissipation. Moreover, the composite anode comprising a practical level of commercial graphite and SiMP contents with pGN operates effectively because of high cycle efficiency and structural integrity, which promises the realization of advanced battery applications.