SnO₂/Graphene Nanocomposite Coated by Carbonized Polyacrylic Acid Hydrogel as a High-Performance Anode for Lithium-Ion Batteries

Tin oxide is regarded as one of the most promising anode materials for lithium-ion batteries. However, the large volume change and low electrical conductivity during charge-discharge process hinder its practical application. In this work, carbon-coated SnO₂/graphene nanocomposite is synthesized by in-situ polymerization of acrylic acid monomer and in-situ carbonization of polyacrylic acid hydrogel on the surface of three-dimensional porous structure SnO₂/graphene. This unique structure ensures the stable combination of SnO₂ nanoparticles with graphene and simultaneously avoids the agglomeration of SnO₂ nanoparticles. Thus, the nanocomposite exhibits stable structure and excellent ionic/electronic conductivity during long-term lithiation/delithiation process. The discharge capacity of carbon-coated SnO₂/graphene nanocomposite remains at 968 mAh g⁻¹ after 50 cycles at 100 mA g⁻¹ and 480 mAh g⁻¹ after 500 cycles at 1000 mA g⁻¹, which exhibits a significant improvement in both cyclability and rate capability for SnO₂-based anode materials.