Highly Stable and Scalable Quasi-Solid Blend Biopolymer Electrolytes for High-Performance Supercapacitor Applications

Abstract

A biopolymer blend composed of alginic acid and carboxymethyl cellulose was identified as a uniform and stable host matrix (BP) for developing redox-activated polymer electrolytes. However, biopolymer-based electrolytes often face challenges related to stability and large-scale fabrication for energy storage applications. To overcome these limitations, the BP matrix was modified with different concentrations of glycerol (G) and cobalt (Co), leading to mechanically robust electrolyte compositions. The resulting metal-ion-doped blend electrolytes exhibited remarkable ionic conductivity, flexibility, and a stable electrochemical window of 1.5 V. The redox-active contributions of the doped electrolytes at nanocomposite electrode interfaces delivered a maximum specific capacitance of 329 F g−1. Furthermore, the electrolyte system enhanced device performance, achieving a specific energy of 45 Wh kg−1 at a power density of 360 W kg−1. The flexible device demonstrated outstanding durability, retaining 90% of its initial performance even after 10,000 charge−discharge cycles. With compact dimensions of 5 × 4 cm, the assembled device powered an RGB LED under different structural configurations.