A High-Performance and Fast-Charging Rechargeable Iron-Ion Battery Using V2O5 Porous Microspheres Cathode

Owing to iron's natural abundance, low cost, and affordability, nonaqueous rechargeable iron-ion (Fe-ion) batteries have the potential for alternative rechargeable energy-storage devices. However, developing cathodes with adequate superior Fe2+ storage during charge-discharge is a major challenge. Herein, V2O5 porous microspheres (V2O5-PMS) are synthesized as efficient cathodes due to their unique characteristics, including high surface area and large interlayer spacing, which provide high electrochemical performance and fast charge kinetics. The nonaqueous Fe-ion battery is fabricated under ambient conditions using mild steel as an anode and a V2O5-PMS cathode. The cyclic voltammetry measurements suggests a high diffusion coefficient of Fe2+ ions in the redox process during charge-discharge. The V2O5-PMS-based cathode shows approximate to 205 mAh g(-1) gravimetric capacity at 33 and approximate to 70 mAh g(-1) at 1 A g(-1) (approximate to 15 C). It exhibits capacity retention of approximate to 70% in 600 cycles at a very high current rate of 3 A g(-1). The impedance spectroscopy measurements are carried out between the cell's cycling to understand the electrode-electrolyte interface resistance over cycling. The four CR-2032 coin cells are assembled in series to glow a white and red light-emitting diode to demonstrate its potential as an alternative energy-storage system.