Low-temperature supercapacitor

• Main Author: Muhammad Ja'far Sodiq Bin Kelana Izrak
• Other Authors: Shen Zexiang
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Energy materials; Engineering::Mechanical engineering::Energy conservation
• Online Access: https://hdl.handle.net/10356/167823
• Institution: Nanyang Technological University

Supercapacitors have emerged as one of the most effective energy storage technologies. Recently, pseudocapacitors have started making waves in the research field. Its fast and reversible faradaic reaction enhances specific capacitance and hence, energy density, which is beneficial for energy storage. However, pseudocapacitors have relatively low power density and cyclic stability. In this report, the components of a Manganese Oxide (MnO2) pseudocapacitor such as its electrode material and electrolyte mixture were varied to improve specific capacitance as well as low temperature stability respectively. For the MnO2 electrode, the amount and type of carbon-based additives (graphene and acetylene carbon black) were explored and were found to have very favourable results. Graphene proved to be the better carbon-based additive and the sample with the largest amount improved specific capacitance by fourfold. For the electrolyte mixture, potassium hydroxide (KOH) solution was compared to a mixture of aqueous sodium chloride (NaCl) and ethylene glycol (EG) to determine their ability to maintain specific capacitance at low temperatures of 0°C to -40°C. The aqueous NaCl-EG mixture was found to be a better electrolyte in achieving this objective, allowing operating temperatures to go as low as -60°C.