Thermoelectric-Powered Supercapacitors Based on Ni–Mn Nanowires Driven by Quadripartite Electrolyte

Thermal energy is copiously available, especially low-grade heat which is typically wasted as a byproduct without use. Tapping into this immense energy reservoir with cost-effective technologies may become a key element for an energy-sustainable economy and society. The utilization of this waste thermal energy holds great potential in space applications for generating electric energy without using a solar panel. With this approach of harvesting heat energy, Ni–Mn composite nanowire-based electrodes synthesized via the electrochemical deposition technique are used to assemble a thermoelectric-powered supercapacitor. For charging purpose, the thermoelectric phenomenon of a quadripartite gel electrolyte [K3Fe(CN)6 + K4Fe(CN)6 + KOH + PVA] is tested. High-grade flexible copper tape used as a substrate can withstand high temperature and is perfectly suitable for thermoelectric devices. The fabricated symmetric device attained a high specific capacitance of 556 F/g at 4 mA in addition to a high energy density of 173.75 W h/kg at 3 kW/kg. Moreover, the fabricated thermoelectric-powered device attains a maximum voltage of ∼60 mV as a result of a temperature difference in the range of 8–10 °C. The proposed supercapacitor offers opportunities for the development of future devices that simultaneously harvest and store energy.