Laser in-situ synthesis of SnO₂/N-doped graphene nanocomposite with enhanced lithium storage properties based on both alloying and insertion reactions

Highlights: • The SnO₂/N-Gr electrode is prepared by a laser in-situ synthesis method. • The SnO₂/N-Gr shows improved lithium storage capacities and rate performance. • Mechanisms of alloying and insertion are related to performance enhancement. - Abstract: This paper reported a SnO₂/N-doped graphene nanocomposite (SnO₂/N-Gr) electrode which was prepared by a laser in-situ synthesis method. When demonstrated as anodes for lithium storage, the SnO₂/N-Gr electrode showed improved lithium storage capacities and rate performance. In details, a reversible capacity of 830 mAh g⁻¹ was obtained after 300 cycles at a current density of 300 mA g⁻¹, and when the current density increased up to 3 A g⁻¹, the SnO₂/N-Gr electrode revealed a high reversible capacity of 600 mAh g⁻¹. It was proven that the excellent electrochemical performance mainly related to a hybrid lithium storage mechanism which combined with alloying and insertion reactions. By introducing huge numbers of micropores and defects on graphene sheets, N-doping increased the number of hosts for lithium insertion and enhanced the Li⁺ diffusion rate in graphene sheets, so both of lithium storage capacities and rate performance were effectively improved. The SnO₂/N-Gr electrode had a short preparing procedure and good electrochemical performance, which hold potential for development of next generation lithium ion batteries with high specific capacities and good rate performance.