A response surface methodology approach to crafting superior performance of potassium salt-based solid biopolymer electrolytes.

• Synthesis of PT/MC/K 2 CO 3 /EC solid polymer electrolytes (SPE) • Design of experiment and analysis of data by RSM. • Optimization and interaction studies by RSM. • Prediction by RSM and experimental validation of optimum response. • Structural studies of optimum sample. • Electrochemical studies of optimum sample. • Fabrication and testing of electrochemical capacitor based on optimum response. In this study, we developed an eco-friendly solid electrolyte by blending pectin (PT) with methylcellulose (MC) and complexed with potassium carbonate (K 2 CO 3) salt and ethylene carbonate (EC) plasticizer. The goal of the study was to understand the salt-plasticizer interaction and to optimize the electrochemical performance using response surface methodology (RSM) within the central composite design (CCD). RSM approach unveiled that K 2 CO 3 and EC interact significantly, impacting the ionic conductivity and potential window of the solid biopolymer electrolytes (SBEs). After optimization, this work achieved ideal conditions with 35.05 wt% K 2 CO 3 and 16.78 wt% EC, yielding an ionic conductivity of ∼ 1 × 10-3 Scm−1 and a 4.77 V potential window. Structural analysis confirmed coordination among constituents and increased amorphous content. This work, therefore, highlights PT/MC/K 2 CO 3 /EC's potential for electrochemical device applications. An electrochemical cell constructed using the optimized sample exhibited the highest specific capacitance of 50.74 Fg–1, as determined by cyclic voltammetry (CV) analysis. [ABSTRACT FROM AUTHOR]