Nano-sized FeSe2 anchored on reduced graphene oxide as a promising anode material for lithium-ion and sodium-ion batteries

High-performance transition metal selenides are considered as promising electrode materials in alkali-ion batteries. However, the poor conductivity limits their further application. Herein, FeSe2 nanoparticles anchored on reduced graphene oxide (FeSe2@rGO) hybrid composites are prepared by a simple hydrothermal method and designed as promising anodes for lithium/sodium-ion batteries. The as-prepared FeSe2@rGO hybrids exhibit superior electrochemical performance with large reversible capacity and excellent cycling stability. In particular, the FeSe2@rGO electrodes deliver a specific capacity of 945.8 mAh g−1 for LIBs and a reversible capacity of 468.8 mAh g−1 for SIBs after 100 cycles at a current density of 100 mA g−1. Besides, the FeSe2@rGO electrodes demonstrate impressed rate capability and high ion diffusion coefficient. The results could enrich electrode materials synthesis methodologies and understand the complex charge–discharge process of metal selenides for next-generation batteries.