Design and Evaluation of a Self-Healing, Highly Stretchable Double-Network Gel Polymer Electrolyte for Potential Use in Wearable Supercapacitors

This work reports the design and synthesis of a novel self-healing and stretchable gel polymer electrolyte (GPE) based on a double-network (DN) architecture combining polyacrylamide (PAM) and gellan gum (GG). The GPE was fabricated via a UV-initiated one-pot photopolymerization process in the presence of Na⁺ ions, which act both as ionic charge carriers and physical cross-linkers through electrostatic interactions. The optimized PG-3 DN GPE exhibited remarkable mechanical performance, achieving a tensile strength of 2.0 MPa and an elongation at break of 400%. Furthermore, the GPE demonstrated high ionic conductivity (0.29 S/cm) and excellent self-healing efficiency (>90%) at 60 °C under ambient pressure, without the need for additional healing agents. Spectroscopic and morphological characterizations (FTIR, XPS, ¹³C NMR, SEM) confirmed the formation of a homogeneous and interconnected porous network that supports efficient ion mobility and structural integrity. The observed improvements in mechanical and electrochemical behavior were attributed to synergistic hydrogen bonding, Na⁺-mediated ionic bridging, and optimized water retention. Compared to conventional GPEs, this PAM/GG-based DN system provides an environmentally friendly, biopolymer-integrated, and scalable platform suitable for next-generation flexible and wearable energy storage applications, particularly in supercapacitors.