In situ fabrication of nitrogen-doped carbon-coated SnO2/SnS heterostructures with enhanced performance for lithium storage

Tin-based compounds have incurred tremendous attention due to their higher specific capacities than their analogues for lithium storage. Unfortunately, the undesirable electrical conductivities and huge volume variations during cycling processes coupled with Li+ intercalation and de-intercalation will lead to severe capacity fading and poor cycling stability. To address these problems, nitrogen-doped carbon-coated SnO2/SnS (SnO2/SnS@N-C) composite was in situ synthesized by virtue of a simple solvothermal reaction and subsequent post-treatment. Herein, the heterostructures between SnO2 and SnS were designed to accelerate charge transfer by using the effect of internal electric field and improve the dispersion among particles. While coating the nitrogen-doped carbon on heterostructures aimed to improve electrical conductivities and relieve huge volume alterations during the processes of Li+ insertion and de-insertion. To our satisfactory, the as-prepared SnO2/SnS@N-C composite as anodes for lithium-ion batteries can display a high specific capacity (1050 mAh g−1 at 100 mA g−1), enhanced rate capability, and long cycle life (550 mAh g−1 after 100 cycles), which outperforms both SnO2@N-C and SnS@N-C. The promotion of electrochemical performance demonstrates that Tin-based anode materials with such optimized structures have broad prospects in the applications of energy storage field.