Reduced graphene oxide doping flower-like Fe7S8 nanosheets for high performance potassium ion storage

Finding easy-to-operate strategy to obtain anode material with well-designed structure and excellent electrochemical performance is necessary to promote the development of the future potassium-ion batteries (PIBs). In this work, we synthesized reduced graphene oxide doping flower-like Fe 7 S 8 nanosheets electrode materials using one-step hydrothermal strategy. The rGO@Fe 7 S 8 composite is composed of homogeneous Fe 7 S 8 and reduced graphene oxide thin nanosheets. This unique structure not only promotes the penetration of electrolyte and increases the conductive of the pure Fe 7 S 8 electrode materials, but also relieves the volume expansion of K + during charge/discharge process. When applied this interesting anode electrode for PIBs, the rGO@Fe 7 S 8 exhibits excellent electrochemical performance. It delivers a high reversible specific capacity of 445 mAh g −1 at 50 mA g −1 , excellent rate performance (284 mAh g −1 at 500 mA g −1 and 237 mAh g −1 at 1000 mA g −1 ), and a high cycling stability at 100 mA g −1 (maintained 355 mAh g −1 after 300 cycles).