Synergistic double-shell coating of graphene and Li 4 SiO 4 on silicon for high performance lithium-ion battery application

We demonstrate that the double-shell coating of graphene and Li4SiO4 on commercial Si nanoparticles as an effective strategy for improving the anode of lithium ion batteries to overcome the two critical concerns, i.e. rapid capacity decay and inferior coulombic efficiency caused by the large-volume changes. It is proven that the double-shell coating enables the formation of a stable hybrid solid electrolyte interphase, leading to much higher coulombic efficiency and longer cycling stability of the Si anodes. Furthermore, the rate performance of Si is significantly enhanced by the outstanding electrical conductivity of inner graphene layers and the excellent ionic conductivity of Li4SiO4 out-shell. The overall results suggest that this new strategy holds promising perspectives in optimizing electrochemical performances of Si anodes, which should promote their practical applications for next-generation lithium ion batteries with increasingly demanded energy density.