Effect of NaClO4 Dopant on Chemical Bond and Electrochemical Characteristic of Benzoyl Kappa-Carrageenan Gel Biopolymer Electrolyte

Gel biopolymer electrolytes based on benzoyl kappa-carrageenan (Bz-kappa car) as polymer host and sodium perchlorate (NaClO4) as dopants are successfully produced. The concentration of NaClO4 is varied from 0.5 to 3.0 wt% to investigate its effects on the chemical bonds and electrochemical characteristic of electrolytes. Characterizations are performed by Fourier-transform infrared spectroscopy (FTIR) and electrochemical impedance analysis (EIS), linear sweep voltammetry, and transference number measurement. Significant changes in the FTIR spectra are detected, which indicate chemical interactions between Bz-kappa car and NaClO4. The ionic conductivity (sigma) of the gel electrolytes increases with higher concentrations of NaClO4, suggesting that NaClO4 is an effective charge carrier in the system. The highest sigma of the gel electrolyte attained at ambient temperature is 1.29 x 10(-3) S cm(-1). The temperature dependence of conductivity is Arrhenian in the studied temperature range and achieves an elevated sigma of 7.90 x 10(-3) S cm(-1) at 373 K with small values in the activation energy (E-a) observed in all the prepared electrolytes. Electrochemical stability of 1.50 V achieves the highest conducting electrolyte by means of linear sweep voltammetry. Transference number measurement confirms that ions predominate the conduction of electrolyte with 0.85 ion transference number.