Sodium storage performance and mechanism of Ag2S nanospheres as electrode material for sodium-ion batteries

Metal sulfides have attracted tremendous attention as electrode materials for sodium-ion batteries due to their high theoretical capacity. In this article, Ag2S nanospheres with 70 nm diameter were prepared by a hydrothermal method. Compared with the bulk Ag2S, the as-prepared Ag2S nanospheres deliver the capacity of 198 mAh/g after 100 cycles at 1C, exhibiting excellent cycling and rate performance as the electrode material for sodium-ion batteries. The remarkable electrochemical performance can be attributed to the shorter Na+ diffusion path in Ag2S nanospheres. Structural characterization reveals that the sodiation processes of Ag2S include intercalation and conversion reactions, which were confirmed by potential relaxation technique (PRT) measurements. •Ag2S nanospheres were prepared with a hydrothermal method.•Ag2S electrode for sodium-ion batteries is firstly investigated.•Ag2S nanospheres exhibit excellent cycle and rate performance for sodium-ion batteries.•Sodiation mechanism of Ag2S is a multi-step reaction, including intercalation and conversion reaction.