Nonaqueous H₃PO₄-Doped Gel Electrolytes

Abstract

Nonaqueous protonic gels incorporating H3PO4 have been synthesized using propylene carbonate (PC), dimethylformamide (DMF), 1-methyl-2-pyrrolidone, ethylene glycol, and several polyglycols as possible entrapped solvents. The properties of these various gels have been studied with the purpose of optimizing the protonic conductivity and understanding the conduction mechanism. Two gel electrolytes, DMF in a network based on glycidyl methacrylate and PC in a network based on methyl methacrylate, were selected for in-depth study because of higher conductivity. The operating temperature range for these electrolytes is from −50 to +100 °C. These were compared with their H3PO4 solution analogues in order to understand the role of the gel network, if any, in the conduction process. Possible conduction mechanisms in these protonic gels are discussed.