Effect of Zinc Oxide Nanofiller on the Ionic Conductivity of Carboxymethyl Cellulose-Based Solid Polymer Electrolyte

The semi-crystalline nature of bio-based solid polymer electrolytes (SPE) can impede ionic mobility, thereby reducing their ionic conductivity. One established method to enhance the ionic conductivity of SPE involves the addition of fillers. In this study, SPE was prepared using a solution casting method, comprising carboxymethyl cellulose (CMC) as the biopolymer host, lithium bis-trifluoromethanesulfonimide (LiTFSI) as the charge carrier, and zinc oxide (ZnO) as the nanofiller. We investigated the impact of ZnO on the electronic and chemical properties of the CMC-LiTFSI SPE through Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). The highest ionic conductivity of 1.94 x 10 -6 S/cm was achieved with 4 wt.% ZnO. FTIR spectra demonstrated complexation between CMC, LiTFSI salt, and ZnO nanofiller. XRD analysis indicated an improvement in the amorphous nature as ZnO was added to CMC-LiTFSI system, which explained the increase in ionic conductivity. In conclusion, ZnO present a promising choice as a nanofiller to enhance the ionic conductivity a of the CMC-LiTFSI SPE system. Keywords: Solid polymer electrolyte; carboxymethyl cellulose; zinc oxide nanofiller; ionic conductivity