Highly conducting corn starch doped ionic liquid solid polymer electrolyte for energy storage devices

Abstract

In this study, a new biopolymer electrolyte (BPE) is successfully developed using corn starch complexed with ammonium iodide (NH₄I) as host, and low viscosity ionic liquid 1-Ethyl, 3-Methyl Imidazolium Thiocyanate (EMImSCN), as a plasticizer. This ionic liquid doped BPE shows high ionic conductivity of the order 10⁻⁴ S/cm and electrochemical stability window more than 3 V, which is suitable for electrochemical application. The ionic transference number (t_ion) of 0.98 confirms the system to be predominantly ionic in nature. Fourier transform infrared spectroscopy (FTIR) shows complex nature, while polarized optical microscopy (POM) gives us an idea about the semi-crystalline nature of BPE. Maximum conducting ionic liquid doped BPE sandwiched electric double layer capacitor (EDLC) and dye sensitize solar cell (DSSC) shows efficient performance.