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 Fe7S8 nanosheets electrode materials using one-step hydrothermal strategy. The [email protected]7S8 composite is composed of homogeneous Fe7S8 and reduced graphene oxide thin nanosheets. This unique structure not only promotes the penetration of electrolyte and increases the conductive of the pure Fe7S8 electrode materials, but also relieves the volume expansion of K+ during charge/discharge process. When applied this interesting anode electrode for PIBs, the [email protected]7S8 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).