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. (C) 2019 Elsevier Inc. All rights reserved.