Hierarchical α-Fe2O3/MnO2/rGO ternary composites as an electrode material for high performance supercapacitors application

• α-Fe 2 O 3 /MnO 2 /rGO heterostructure was synthesised by a Solvothermal method. • Heterostructure material shows a high specific capacitance of 447F g −1 at optimum current density at 1 A g −1 value compared with pure and binary composites. • The electrode exhibited excellent capacitance retention of 96 % after 10,000 cycles. • The α-Fe 2 O 3 /MnO 2 /rGO heterostructure device exhibited a high energy density of 13.2 Wh kg −1 . Transition Metal oxide decorated graphene nanosheets have accumulated a lot of consideration due to their potential applications in electrochemical energy storage devices especially in supercapacitors (SCs). Nanostructured mixed multi-metal oxides have been employed as promising electrodes for creating more active site for electron transfer. All-solid-state asymmetric supercapacitors (ASC) have significant theoretical capacitance, good rate capability, and excellent cycling stability suitable for energy storage device fabrication with optimum energy and power density. Here, we demonstrate a Solvothermal route to synthesis ternary α-Fe 2 O 3 /MnO 2 /rGO composites.. The hybrid ternary composites in 3-electrode configuration showed maximum capacitance of 447 F g −1 at optimum current density at1A g −1 and 96 % of capacitance retention after 10,000 GCD cycles at 10 A g −1 in an alkaline medium. The fabricated ASC device with ternary composites (positive) and negative electrodes (rGO) separated by PVA/KOH gel-electrolyte separator exhibits maximum cell voltage of 1.4 V with high specific capacitance of 97 F g −1 at 1 A g −1 . Additionally, the assembled device delivered a high energy density of 13.2 W h kg −1 and a high power density of 6124 W kg −1 with an excellent capacitance retention of 92% and columbic efficiency of 96 % preserved over 5000 cycles at 10 A g −1 with good reversibility. Besides, the Solvothermal strategy supports for the fabrication of metal oxide could be applicable for other metal oxide electrode materials preparation.