Studies on improvement in electrochemical performance of manganese oxide and its composites for solid state supercapacitor application

Abstract

The growing global demand for sustainable and efficient energy storage devices has greatly increased interest in the development of high-performance supercapacitors. These devices are particularly important because they combine high power density, fast charge discharge rates, and long cycle life, making them suitable for next-generation portable and flexible electronics. Among various electrode materials, manganese oxide (MnOand#8322;) stands out due to its low cost, environmental friendliness, natural abundance, and high theoretical specific capacitance. However, its practical application is still hindered by certain limitations, including poor intrinsic electrical conductivity and structural instability during long-term cycling. newlineTo overcome these limitations, this work focuses on improving electrochemical performance of MnO2 thin film synthesis by varying temperature, preparing composite and device fabrication. First of all, MnOand#8322; thin films were directly synthesized on stainless steel substrates via a hydrothermal method by varying the deposition temperature from 80 oC to 120 oC. This study helped in understanding how temperature affects nanostructure formation, surface area, and charge storage behaviour. Optimized thin films achieved high specific capacitance and better cycling stability compared to other samples. newlineTo further enhance the performance, MnOand#8322; was composited with V2O5 by using simple hydrothermal method. The addition of V2O5 provided multiple redox states, which increased the overall charge storage capability. Additionally, polyaniline (PANI), a well-known conducting polymer, was composited with MnOand#8322; using an electrodeposition followed by hydrothermal method. The electrodeposition reaction time was systematically varied to evaluate its influence on the structural and electrochemical properties of the resulting films. MnO2 - PANI composite not only improved the electrical conductivity of MnOand#8322; but also introduced synergistic redox activity, enabling faster charge transport and enhanced electrochemical perform