A novel molybdotungstosilicate gel electrolyte with wide electrochemical stability window

Abstract

New hybrid gel electrolyte [MIMPS]4SiW11MoO40 (IL-SiW11Mo) has been synthesized from the heteropoly acid H4SiW11MoO40 and 1-(3-sulfonic group) propyl-3-methyl imidazolium (abbreviated as MIMPS). The results of FTIR and XRD reveal that the synthesized polyoxometalate-based gel electrolyte possesses lamellar structure and exhibits the characteristic thermo-tropic liquid-crystalline behavior, which can undergo a phase transformation from a viscous gel state to liquid state below 100 oC. Its ionic conductivity of up to ~10-3 S cm-1 was observed above the phase transformation temperature. The electrochemical stability potential window (ESW) of IL-SiW11Mo was found to be about 4V at room temperature. The electrochemical impedance spectroscopy (EIS) was carried out to study the capacitance and ion mobility of IL-POM used as electrolyte. The results show that IL-SiW11Mo has high capacitance and fast ion mobility.