Replacing synthetic polymer electrolytes in energy storage with flexible biodegradable alternatives: sustainable green biopolymer blend electrolyte for supercapacitor device

Abstract

Flexible free-standing blended solid biopolymer electrolytes (BSBEs) were developed using chitosan (CS) and potato starch (PS) as the host biopolymers for the biopolymer matrix. Potassium thiocyanate (KSCN) was used as the cation provider, while non-toxic glycerol (GCL) was employed as a plasticizer to reduce resistance and enhance the amorphousness of the BSBE films. The structural, morphological, and electrical analyses demonstrated encouraging properties for the BSBE films. The addition of GCL resulted in increased dissociation of KSCN. Deconvoluted Fourier transform infrared (FTIR) spectroscopy was utilized as an accurate method for extracting ion transport parameters. The highest ambient temperature conductivity of 1.40×10−3Scm−1 is recorded at 36 wt% of GCL. The best ion conducting film exhibited a wide potential stability of 2.72 V and an ion transference number (tion) close to unity, with a value of 0.978. The fabricated EDLC demonstrated approximately rectangular cyclic voltammetry (CV) performance and fast-rate charge-discharge behavior with a specific capacitance (Cspc) of 42.11Fg−1. The galvanostatic charge-discharge (GCD) test confirmed the capacitive characteristics of the cell, exhibiting good cyclic stability and excellent outcomes in terms of energy (Ed) and power (Pd) densities over numerous cycles.