Fabrication of ternary silicon-carbon nanotubes-graphene composites by Co-assembly in evaporating droplets for enhanced electrochemical energy storage

Abstract

Silicon (Si) particles are considered as promising anode electrode materials in lithium ion batteries (LIBs) because of high theoretical energy capacity of 3579 mA h/g. However, the large volume expansion of Si during the cycling process cause structural degradation and pulverization of the electrode, and this leads to solid electrolyte interphase (SEI) film reformation. In order to solve the problem, wrapping of Si particles with carbon materials is considered as an effective solution. In this study, we report ternary silicon core-carbon nanotubes winding-graphene shell (Si-CNTs-GR) nano-structured composites, which can cushion volume change of Si core particles by carbon nanotubes (CNTs) winding and protect SEI layer by graphene (GR) shell. The composites were fabricated using a facile aerosol process followed by heat-treament for anode materials of LIBs. The average particle size of ternary Si-CNTs-GR increased with respect to concentrations of CNTs at fixed other conditions. The as-prepared composites exhibited higher performance as LIB anodes such as capacity and coulombic efficiency than commercial Si particles or Si-GR composites. The ternary Si-CNTs-GR composites showed high capacity of 1700 mA h/g at 50 cycles.