Facile Preparation of Graphene/SnO₂ Xerogel Hybrids as the Anode Material in Li-Ion Batteries

SnO₂ has been considered as one of the most promising anode materials for Li-ion batteries due to its theoretical ability to store up to 8.4 Li⁺. However, it suffers from poor rate performance and short cycle life due to the low intrinsic electrical conductivity and particle pulverization caused by the large volume change upon lithiation/delithiation. Here, we report a facile synthesis of graphene/SnO₂ xerogel hybrids as anode materials using epoxide-initiated gelation method. The synthesized hybrid materials (19% graphene/SnO₂ xerogel) exhibit excellent electrochemical performance: high specific capacity, stable cyclability, and good rate capability. Even cycled at a high current density of 1 A/g for 300 cycles, the hybrid electrode can still deliver a specific capacity of about 380 mAh/g, corresponding to more than 60% capacity retention. The incorporation of graphene sheets provides fast electron transfer between the interfaces of the graphene nanosheets and the SnO₂ and a short lithium ion diffusion path. The porous structure of graphene/xerogel and the strong interaction between SnO₂ and graphene can effectively accommodate the volume change and tightly confine the formed Li₂O and Sn nanoparticles, thus preventing the irreversible capacity degradation.