Agarose Based Biopolymer Gel Electrolyte for Electrochemical Applications

A novel electrochemically stable biopolymer gel electrolyte has been reported. To develop biopolymer electrolyte, the solution is comprised of potassium iodide and ionic liquid 1-ethyl-3-methylimidazolium dicyanamide with varying solvents such as distilled water (H₂O), Dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) have been added to the Agarose matrix at room temperature and further used in the application of dye sensitized solar cell (DSSC), extra iodine was added in the matrix. Details of the fabrication, characterization and application of the biopolymer gel electrolyte films based on Agarose is given in the paper. Structural, electrical and electrochemical studies have been done on samples which demonstrate promising characteristics of the biopolymer gel electrolyte. The possible conformational/structural changes in the biopolymer due to the formation of a complex nature, entrapment of iodine solution, crystallinity and amorphous nature have been investigated by Fourier transform  infrared (FTIR), Polarized optical microscopy (POM) and X-ray diffraction (XRD). Complex impedance spectroscopy showed the manifold enhancement in ionic conductivity by salt doping. The conductivity maxima were obtained near 60:40 compositions at room temperature. The temperature dependence of electrical conductivity of biopolymer–ionic liquid blends and gel polymer electrolyte follows the Arrhenius behavior. The dielectric studies and ion transport number measurement confirms the ionic conduction in the gel polymer electrolyte. DSSC was fabricated using maximum conductivity and comparative measured values of the FF, Voc, Jsc and efficiency at 100mW/cm were tabulated.