Highly monodispersed graphene/SnO2 hybrid nanosheets as bifunctional anode materials of Li-ion and Na-ion batteries

Abstract

Metal oxides/graphene hybrid materials have been widely considered as promising anodes for next-generation lithium/sodium ion batteries. However, their performance enhancement is always hindered by the unavoidable π-π restacking of graphene nanosheets (GNs) during solution removal processes. To address this issue, we develop a monodispersed GN/SnO2 hybrid material basing on a facile cold-quenching technology. Due to the distinctly wrinkled surface feature of the hybrid graphene nanosheets, their restacking behavior is inhibited and the monodispersed state is well maintained. It is also found the content of SnO2 in the hybrid plays a critical role in the evolvement of the wrinkled structure of GNs. Benefiting from the rational structure design featured with the monodispersed state of GNs and the homogenous dispersion of SnO2 nanoparticles (NPs), the hybridized electrode material exhibits a high reversible capacity of 1147 mAh g−1 at 100 mA g−1 after 200 cycles and favorable rate capability (759 mAh g−1 at 1000 mA g−1) when employed as anode material of Li-ion batteries. While for the application in Na-ion batteries, this GN/SnO2 electrode can perform a high reversible capacity (314 mAh g−1 at 100 mA g−1) and present a stable long-term cycling stability with a favorable capacity retention of 77% after 500 cycles. This work provides an effective route to solve the commonly existed restacking issue of graphene-based composites, which is universal to explore other NPs/graphene materials for the applications in catalysis, gas sensors and electrochemical energy storage, etc.