Porous SnO2@C/graphene nanocomposite with 3D carbon conductive network as a superior anode material for lithium-ion batteries

Abstract

Porous nano-sized SnO2@C/graphene electrode material with three-dimensional carbon conductive network was designed and prepared. The carbon shell was introduced to suppress the aggregation of nanoparticles and undesired reactions. The excellent electronic conductivity can be guaranteed by a 3D carbon conductive network consisted of graphene sheets and carbon shell. The porous structure can facilitate liquid electrolyte diffusion into the bulk materials. As a result, the as-prepared SnO2@C/graphene nanocomposite as an anode material for lithium-ion batteries exhibits high reversible specific capacity, outstanding cyclability and good rate capability. The first reversible specific capacity is as high as 1115 mAh g−1 at a specific current of 100mAg−1. After 100 cycles at different specific currents from 100 to 1000mAg−1, the reversible specific capacity was still maintained at 1015 mAh g−1 at the specific current of 100mAg−1. Even at the high specific current of 1000mAg−1, the reversible specific capacity is still as high as 499 mAh g−1, higher than the theoretical specific capacity of the commonly used graphite anode material (372 mAh g−1). The results give the clear evidence that the electrochemical performance of graphene-based electrode materials can be improved by designing proper structure. The preparation approach of porous SnO2@C/graphene nanocomposite reported in this paper may also be applied to fabricate other porous metal oxide@C/graphene electrode materials for high performance lithium-ion batteries.