Bi-functional nitrogen-doped carbon protective layer on three-dimensional RGO/SnO2 composites with enhanced electron transport and structural stability for high-performance lithium-ion batteries
Three-dimensional reduced graphene oxide@SnO2@nitrogen-doped carbon (3DG@SnO2@N-C) composites are designed as high efficiency anode materials for lithium-ion batteries. The SnO2 particle size, surface area and pore size distribution of the 3DG@SnO2@N-C could be simply controlled by altering the GO dosages. The optimized 3DG@SnO2@N-C electrode demonstrates a reversible capacity of 1349.5 mAh g-1 after 100 cycles at the current density of 100 mA g-1. Based on the structural and electrochemical dynamic tests, the bi-functional N-doped carbon coating layer could serve as both conductive channel for electron transport and as buffer layer to alleviate the volume change of embedded SnO2 NPs. In addition, the cross-linked conducting 3DG with porous structure attributes to the reduced electron transport and Li ion diffusion resistances, which finally leads to the enhanced cycling stability and rate performances.