Design of potassium ion conducting PVA based polymer electrolyte with improved ion transport properties for EDLC device application

Abstract

This work presents a report on the preparation of plasticized polyvinyl alcohol PVA-based polymer electrolytes using solution cast technique and their characteristics using a number of electrochemical techniques. Electrical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and transfer number measurement (TNM) techniques were examined on the prepared films to determine the conductivity, decomposition voltage and ion transference number, respectively. The cyclic voltammetry (CV) and charge-discharging measurements were implemented on an assembled EDLC device to estimate the charge storage process and evaluate the device performance, respectively. The EIS was employed for measuring the direct current (DC) electrical conductivity of the films and calculating the ion transport parameters. The CV and charge-discharging responses were used to estimate the capacitance and stability, respectively. The influence of plasticization on the polymer electrolytes was investigated in terms of electrochemical properties. The TNM measurements were used to determine te and tion respectively. The obtained ionic transference number, tion for the electrolytes incorporated with 40 wt.% and 50 wt.% of glycerol content were found to be 0.969 and 0.944, respectively. The LSV study was used to identify the decomposition voltage of the sample. The absence of redox peaks was proved via CV technique, indicating the mechanism of the charge storing process that comprised ion accumulation at the interfacial region. The initial specific capacitance (Cs) of the fabricated EDLC displayed the value of 152.4 F/g.

Keywords

• Plasticized electrolyte
• PVA
• Potassium iodide (KI)
• EEC modeling
• Transport properties
• EDLC device