To achieve controlled specific capacities of silicon-based anodes for high-performance lithium-ion batteries

Abstract

Silicon-based materials are expected to be the next generation of anode materials for lithium-ion batteries (LIBs). However, the electrode structure will be damaged due to large volume expansion during the lithiation process, resulting in a rapid decay of the battery performance. Nanostructures, porous structures, and carbon coatings have been shown to be effective in reducing the effect of volume expansion. In this work, porous carbon coated silicon (Si/PC) nanoparticles were prepared to suppress the effect of silicon volume expansion while improve the infiltration of electrolyte and the diffusion of lithium ions. The prepared Si/PC nanoparticles were mixed with commercial graphite in different mass ratios as anode materials for LIBs, which can effectively control the specific capacities of the anodes and help the practical applications by reducing the production cost. As the mass ratio of the prepared Si/PC nanoparticles to commercial graphite is 2:1, the first discharge specific capacity is 1586.3 mA h g−1 with an initial coulombic efficiency of 82.1% at a current density of 200 mA g−1. After 250 cycles at 1000 mA g−1, the capacity retention rate is 86.8%. The full cell with LiNi0.8Mn0.1Co0.1O2 as cathode shows an excellent cycle stability with a high stack cell energy density of 882.3 Wh/L.