Tailoring bismuth manganese oxide nanostructures for enhanced energy storage and conversion: Role of annealing temperature

Abstract

This research work reports the successful preparation of bismuth manganese oxide (BMO) through the hydrothermal technique and investigates the influence of annealing temperature on physicochemical properties as well as the electrochemical performance of BMO nanostructure. The physio-chemical investigation confirms the formation of BMO NSs. The electrochemical study reveals the annealing temperature affects its supercapacitive and OER electrochemical performances. The electrochemical measurement reveals BMO NSs have 485 F/g specific capacitance at a low scan rate (10 mV/s) in 1.0 M KOH. Moreover, the sample shows around 92 % capacitance retention even after 5000 charging/discharging cycles. The asymmetric supercapacitor device also shows 79 F/g capacitance at 4 mA/cm² with a capacitance retention of 78 % up to 5000 cycles. The sample exhibits 28 Wh/kg and 1600 W/kg, energy and power density respectively at the same current density (4 mA/cm²). In terms of OER performance, the BMO-500 electrode shows an overpotential (341 mV), Tafel slope (76 mV/dec), and the value of electrochemical active surface area (ECSA) is 307 cm² which helps to enhance the electrochemical performance. Overall study reveals that BMO is an effective catalyst in electrocatalysis (EC) and supercapacitors (SC).