Reduced graphene oxide doping flower-like Fe_(7)S_(8) nanosheets for high performance potassium ion storage

摘要

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 mAhg^(-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).