S-Doped Carbon-Coated FeS₂/C@C Nanorods for Potassium Storage

Potassium-ion batteries (PIBs) are promising scalable energy storage system; however, one of the challenges for its potential application is the huge volume variations during cycling due to the insertion/extraction of large size potassium ions. Here, we fabricated the S-doped carbon-coated rod-like FeS /C@C, which not only effectively alleviate the volume variations upon cycling but also can improve electrical conductivity and maintain the structural integrity. As an anode material for PIBs, the rod-like FeS /C@C electrodes delivered excellent rate performance (175 mA h g at 0.5 A g ) and stable cycle performance (262 mA h g after 100 cycles at 0.1 A g ). The superior excellent performance is associated with the unique structure of FeS /C@C. The as-synthesized FeS /C@C is demonstrated to be a potential anode for PIBs. 2 2 2 2 −1 −1 −1 −1