イオン液体を用いたエネルギー貯蔵デバイス

Abstract

Molten salts and ionic liquids are potential electrolytes working in a wide temperature range and attracting attention to construct safe energy storage devices. In this study, the intermediate-temperature operation of secondary batteries has been attempted by the authors to enhance ion transport and electrode kinetics. For sodium secondary batteries, the NASICON-type Na3V2(PO4)3 positive electrode achieves high rate performance and long cycle life. Symmetric cell impedance spectroscopy revealed the considerable decrease in interfacial resistance with increasing operating temperature. The FeF3 positive electrode for the lithium system also exhibits highly enhanced behavior at intermediate temperatures, which also contributes to reveal the reaction mechanism. Zinc chloride-based molten hydrate is demonstrated as an advantageous electrolyte to provide stable zinc metal deposition/dissolution and oxygen reduction/evolution reactions, which indicates its possible use as an electrolyte for zinc-air secondary batteries.