An ultra-stable anode material for high/low-temperature workable super-fast charging sodium-ion batteries

Abstract

• Develop a strategy of 3D hierarchical FeSe 2 /rGO hybrids for anodes in SIBs. • The FeSe 2 /rGO anode exhibits extraordinary rate capacity and stable cycling life. • The FeSe 2 /rGO anode has excellent feasibility from –40℃ to 60℃. • FeSe 2 /rGO//Na 3 V 2 (PO 4 ) 3 /C full-cell delivers a high and stable energy density. 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 FeSe 2 /rGO hybrids by a rational hydrothermal method for anodes in SIBs. The FeSe 2 /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℃). Besides, the FeSe 2 /rGO// Na 3 V 2 (PO 4 ) 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 FeSe 2 /rGO hybrid SIBs as an ideal rechargeable battery for the next-generation energy storage system.