Electrochemical kinetics of a novel electrode material comprising different phases of MnO2 (Mn2O3, γ-, λ-, and δ-), graphite, and PVDF

Electrochemical capacitors have drawn lot of interest, to make them commercially viable, the right nanomaterials must be found to construct a stable electrode with considerable capacitance, transition metal oxide are promising agent due to several valence shells for charge transfer, a high theoretical specific capacitance, and variable redox properties. In this work, four different phases of MnO2 were synthesised using facile chemical reduction method, coprecipitation method, hydrothermal method, and biological method. The phases are used to synthesise novel composite using graphite (additive) and PVDF (binder) in the ratio of 80:10:10 b y ultrasonic treatment. To create the electrodes, specific amount of the composite are pasted onto a substrate made of FTO (fluorine-doped tin oxide). The sequence in which the capacitance values decline is lambda- > gamma- > delta- MnO2> Mn2O3, in which, lambda-MnO2 demonstrated greatest specific capacitance of 326.4 F/g. Moreover, other electrothermal performance parameters such as energy and power density are observed as 62.6 Wh/Kg and 493 W/kg for lambda-phase of MnO2. Further, we obtained an excellent potential widow of 1.6 V with a basic aqueous electrolyte.