As a potential anode material for potassium-ion batteries (PIBs), bimetallic sulfides are favored by researchers for their high specific capacity, low cost, and long cycle life. However, the non-ideal diffusion rate and poor cycle stability pose significant challenges in practical applications. In this work, bimetallic sulfide CuSbSy@C with a yolk-shell structure was synthesized by in situ precipitation and carbonization. When CuSbSy is applied in the anode of PIBs, it can provide the desired capacity and reduce the volume expansion of the compound through the synergistic effect between copper and antimony. At the same time, the existence of the nitrogen-doped carbon shell confines the material within the shell while improving its electrical conductivity, inhibiting its volume expansion and aggregation. Therefore, CuSbSy@C exhibits a satisfactory capacity (438.8 mAh g−1 at 100 mA g−1 after 60 cycles) and an excellent long cycle life (174.5 mAh g−1 at 1000 mA g−1 after 1000 cycles).
