High power density supercapacitor, using a fast ion conducting, flexible, economical, and environment benign polymer-in-salt-electrolytes (PISEs)

Abstract

High-performing supercapacitor requires high and fast ion conducting electrolytes with a wide Electrochemical Stability Window (ESW). Polymer-In-Salt-Electrolytes (PISEs), having diffusion type of ion transport, much faster than polymer coupled ion transport relative to traditional Salt-In-Polymer-Electrolytes (SIPEs), are one such possible electrolyte that can be used for supercapacitors. The present paper discusses the synthesis and characterization of a flexible, high ion conducting (σ ∼ 0.05 Scm−1), having fast ion movement (ion relaxation time (τ) ∼μSec), economical, easy to handle and environment benign PISEs, with wide ESW (∼6 V), whose properties are stabilized with respect to ambient humidity changes. The electrolytes are synthesized by adding magnesium nitrate (Mg (NO<inf>3</inf>)<inf>2</inf>) to glutaraldehyde (GA) crosslinked corn starch using the solution cast technique. The work also discusses the effect of the lattice energy of salt on the mechanical and electrochemical properties of electrolytes. The fabricated supercapacitor has a specific capacitance of ∼750 Fg-1 and power density ∼2 kW kg−1, having coulombic efficiency >95 %. The Ragone plot has indicated that the device is in the Ultracapacitor range. Fabricated supercapacitor (∼25 cm2 area) is capable of glowing a Light Emitting Diode (LED) for ∼3 min, proving its potential as an electrolyte for future commercial energy storage devices. © 2025 Elsevier B.V.