Phosphorus doping induced the co-construction of sulfur vacancies and heterojunctions in tin disulfide as a durable anode for lithium/sodium-ion batteries

Abstract

The reasonable design of electrode materials with heterojunctions and vacancies is a promising strategy to elevate their electrochemical performances. Herein, tin-based sulfide composites with heterojunctions and sulfur vacancies encapsulated by reduced graphene oxide (SnS_2−xP_x/RGO) were successfully designed and synthesized via a facile hydrothermal assisted phosphating method. The introduction of sulfur vacancies and construction of SnS–SnS₂ heterojunctions were realized simultaneously by the phosphating process. The synergistic effect of the heterojunction, sulfur vacancy and phosphorus-doping could improve the conductivity, accelerate the ion transport dynamics, and enhance structural stability. Thus, high-rate, long-term cycling stability was observed for Li-half cells (337 mA h g⁻¹ maintained after 3000 cycles at 10 A g⁻¹) and Na-half cells (199 mA h g⁻¹ maintained after 4000 cycles at 2 A g⁻¹). The design strategy can effectively improve the energy storage performance of tin based sulfides and can be extended to other metal sulfides.