IMPROVING ELECTROCHEMICAL CAPACITOR PERFORMANCE THROUGH STUDIES OF MANGANESE OXIDE HYDRATION AND REDUCED GRAPHENE OXIDE SELF-DISCHARGE

Abstract

Electrochemical capacitors (ECs) store energy in a double layer of charge at an electrode/electrolyte interface and/or through rapid redox reactions. The first project discussed herein is a comprehensive study of the effect drying/storage procedures have on manganese oxide (MnOx)’s performance as an EC material. Capacitive properties are enhanced in hydrous MnOx; power-related properties are enhanced in anhydrous MnOx. A novel film synthesis combining hydrous and anhydrous films is developed, generating films with benefits of both hydrous and heat-treated MnOx. The second project discussed herein addresses self-discharge (SD), a spontaneous potential loss following charging, in reduced graphene oxide (rGO). Carbon oxidation is a minor contributor to SD, while charge redistribution, the spontaneous movement of charge within a material, causes significant SD. Differentiating between these phenomena proves challenging; both processes present similar SD profiles. A method to discern between these mechanisms is presented, determining both processes contribute to rGO SD.