Bilayer-graphene-coated Si nanoparticles as advanced anodes for high-rate lithium-ion batteries

Abstract

Silicon is a promising anode material for the next-generation of high-specific-energy lithium-ion batteries (LIBs), but commercial silicon still has difficulty in gaining both high rate capability and long cycle life for practical application due to poor electrical conductivity and an unstable solid electrolyte interface. Here, a simple electrode with bilayer-graphene-coated Si nanoparticles embedded in a porous current collector is adopted and exceptional electrochemical performance is obtained in lithium-ions batteries. A possible mechanism is analyzed from the insight provided from the conductivity balance between electrons and ions. Used as binder-free and additive-free anodes, the Si composite displays good rate capacity (up to 50 A g−1) and cycling stability (3000 cycles with ∼89% capacity retention). Coupled with a possible physical insight, economical and feasible fabrication process, the electrode designs developed are likely to stimulate more opportunities for the next-generation high-specific-energy LIBs with enhanced power. It is further demonstrated that even in a full-cell electrochemical test, it is stable for 260 cycles and 87% capacity retention is achieved.