Effect of hydrothermal temperature variation on electrochemical performance of manganese oxide thin films for supercapacitor application

In the present work, α-MnO₂ thin films are deposited on a stainless steel substrate using the hydrothermal method by varying hydrothermal temperature. The impact of different hydrothermal temperatures on the structural, morphological and electrochemical performance of prepared thin films is investigated. The XRD studies confirm the tetragonal crystal structure of prepared MnO₂ thin films. The electrochemical behaviour was studied using three-electrode system in 1 M KOH electrolyte. The high electrochemical performance with a maximum specific capacitance of 442 F g⁻¹ at a scan rate 5 mV s⁻¹ and energy density of 62 Wh kg⁻¹ at a power density of 5.2 kW kg⁻¹ has been obtained. The specific capacitance shows 90% capacitance retention after 2000 GCD cycles.