Energy Storage Performance of Plasticized PVA-Based Electrolyte: Electrical and Electrochemical Properties

The substitution of liquid electrolytes with solid biomaterials has generated considerable interest. This research focuses on exploring plasticized SPEs composed of poly(vinyl alcohol)/lithium perchlorate (PVA/LiClO 4 ) with different concentrations of glycerol (Gly). The main objective is to assess their potential application in electrochemical double-layer capacitors (EDLCs). To achieve this, the electrical, dielectric, and energy-related characteristics of the plasticized solid polymer electrolytes (SPEs) were thoroughly investigated using advanced techniques. EIS findings revealed an increasing trend in the ionic conductivity of the plasticized SPEs as the amount of plasticizer was increased, reaching an optimum value of 2.51 × 10 –5 S/cm. The reason behind the enhanced ionic conductivity of the plasticized SPEs lies in the creation of charge-transfer complexes and the enlargement of amorphous regions within the SPE matrix. At room temperature, the sample containing 30% Gly displayed the highest ionic conductivity among the tested samples with a relaxation time of 9.24 × 10 –6 S. Furthermore, the plasticized SPE displayed a broad potential window of 2.27 V, demonstrating its capacity to withstand a wide range of voltages. Moreover, it exhibited a cation transference number of 0.984, indicating efficient cation transport within the electrolyte. The SPE film with the uppermost conductivity was used to construct EDLC, which has a capacitance of 17.5 F/g from the GCD test and good performance stability in terms of energy and power densities.