Self-assembled monodisperse FeSe2 microflowers as an advanced anode material for sodium ion batteries

Abstract

Transition metal selenides have aroused increasing interest for application in sodium ion batteries (SIBs) due to their high theoretical capacities and good cycling stability. Here, monodisperse FeSe₂ microflowers assembled from closely aligned nano/microrods are synthesized by a simple solvothermal method and used as an anode material in SIBs. The monodisperse FeSe₂ microflowers show excellent sodium storage performance with a large reversible capacity of 372.7 mA h g⁻¹ at 10 A g⁻¹ and a long-term cycling capacity of 397.4 mA h g⁻¹ at 1.0 A g⁻¹ after 1600 cycles (91% capacity retention). Moreover, the electrochemical kinetic analysis confirms that the excellent pseudocapacitive behavior accounts for the superior sodium storage performance facilitated by the unique micro-nano hierarchical structure.