An Ultra−Stable Anode Material for High/Low−Temperature Workable Super−Fast Charging Sodium−Ion Batteries

Abstract An ideal rechargeable battery will possess the merits of high specific capacity, long cycling stability, short charging time, high initial coulombic efficiency, wide working temperature range, and low cost. Sodium−ion batteries (SIBs) are expected as the next generation of energy storage devices, but achieving the above features is still a major challenge. Herein, we have developed the 3D hierarchical FeSe2/rGO hybrids by a rational hydrothermal method for anodes in SIBs. The FeSe2/rGO hybrid SIBs exhibit high rate capacity (205.0 mAh g−1 at 75 A g–1 vs 458.6 mAh g–1 at 0.5 A g–1), ultra−stable cycling life (417.7 mAh g–1 after 6000 cycles at 5 A g–1 with a rather low decay rate of only 0.0006% per cycle), extremely high initial columbic efficiency (∼98.6%), and excellent feasibility in a wide temperature range (–40 to 60 °C). Besides, the FeSe2/rGO// Na3V2(PO4)3/C full cell delivers an energy density about 145 Wh kg-1 after 200 cycles at 0.15 A g-1 (286 W kg-1). The excellent electrochemical performances of FeSe2/rGO hybrid SIBs as an ideal rechargeable battery for the next−generation energy storage system.