All layered iron vanadate (FeV₃O₉.2.1H₂O) as electrode for symmetric supercapacitor application in aqueous electrolyte

Iron vanadate (FeV₃O₉.2.6H₂O) which belongs to a group of transition metal vanadates with characteristics of relatively large working potential window, multiple electrochemical reactions, which gives it high specific capacitance, makes them promising electrode material for supercapacitor application. In this report, we synthesized layer structured FeV₃O₉.2.1 H₂O (FVO), with lesser water content via sol-gel method. Our FVO material demonstrated excellent electrochemical activities as both positive and negative electrodes in three-electrode system using aqueous electrolyte with specific capacitance of 73 F g⁻¹ and 291 F g⁻¹, respectively. Additionally, we employed FVO in two-electrode symmetry system where FVO electrode serves as both anode and cathode. It exhibited high capacitance of 83 Fg⁻¹ with 92% initial capacitance retention after 6000 cycles, and high energy density of 36 Wh kg⁻¹.