K. Huynh, B. Maddipudi, V. Amar, A. Shende, R. Shende
South Dakota School of Mines and Technology,
Keywords: hydrochar, CHTL, asymmetric supercapacitor, cyclic voltammetry, GCD, EIS
Summary:Scientific community is striving for novel energy storage devices with superior power/energy density. Among these devices, asymmetric supercapacitors (ASCs) typically have higher power density as compared to batteries whereas higher energy density as compared to capacitors. ASC is fabricated with two dissimilar electrodes and an electrolyte. Commercially available electrode materials such as high surface area activated carbon, graphene, and carbon nanotubes are very expensive. In this study, we derived a relatively inexpensive hydrochar material using the catalytic hydrothermal liquefaction (CHTL) processing of biomass/waste residue such as pinewood, cornstover, and a biomass mixed with plastic waste. The hydrochar was further activated and used as one of the electrodes. ASCs were fabricated with activated hydrochar and ferrite electrodes, and their performance was tested. Superior electrochemical performance of ASC was observed for the hydrochar after chemical and thermal activation steps. As fabricated ASCs were charged for 10 minutes and their charge-discharging cycles were analyzed by cyclic voltammetry to determine the specific capacitance. Preparation of electrode materials and electrochemical performance of ASCs will be presented.