Insight into structure-property correlations in plasticized sodium carboxymethyl cellulose/pectin blend-based polymer electrolyte for EDLC application

This work focuses on the development of plasticized solid polymer electrolytes (SPEs) for electrochemical double-layer capacitors (EDLCs) application. The developed material, consisting of sodium carboxymethyl cellulose (NaCMC), pectin (PC), glycerol, and lithium perchlorate (LiClO4), was prepared using the solution casting method. To assess the performance of the prepared plasticized SPEs, several methods were employed, including Fourier transform infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD), Electrical impedance spectroscopy (EIS), dielectric properties, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and linear sweep voltammetry (LSV). FTIR confirmed the successful interaction between the functional groups of the plasticized polymer blend and the cations (Li+) of the salt. Similarly, EIS revealed that the sample containing the highest salt concentration (25 wt%) showed the highest ionic conductivity measured at 3.55 × 10−4 S cm−1. According to LSV analysis, this sample demonstrated the capability to operate safely within a voltage limit of 3.3 V. The fabricated EDLC cell exhibited a nearly rectangular curve in cyclic voltammetry (CV) analysis and a triangular pattern in galvanostatic charge-discharge (GCD) tests. These curves confirm the capacitive behaviour of the EDLC cell. Finally, the electrochemical parameters of the EDLC cell including the specific discharge capacitance (Cspc), energy density (Ed), and power density (Pd) were determined to be (4.2 F g-1), (0.5 Wh kg−1), and (14 W kg−1) respectively. •Innovative plasticized solid electrolytes based on NaCMC and PC was developed.•LiClO4 improved the ionic conductivity of solid biopolymer electrolytes.•Sample with 25 wt% of LiClO4 showed a conductivity of 3.55 × 10−4 S cm−1.•After 3000 cycles of GCD the Cspc exhibited 5.34 F/g at a scan rate of 5 mV S−1.