Self-Healing Eutectogel Electrolytes for Flexible Supercapacitors

Gel electrolytes have emerged as key components in energy storage devices. However, conventional gel electrolytes often exhibit limited deformation resistance and inadequate mechanical recovery under sustained external stress, which compromises their long-term operational stability. Herein, we report a self-healing eutectogel electrolyte comprising a choline chloride-ethylene glycol deep eutectic solvent (ChCl-DES) as the dispersion medium and a poly[2-(hydroxyethyl acrylate)] (PHEA) polymer network. The incorporation of boric acid (BA) and polyethylene glycol (PEG) enables the formation of dynamic borate ester bonds through interactions with hydroxyl groups. The reversible rupture and reformation of these dynamic covalent linkages impart robust self-healing capabilities to the material. The resulting eutectogel achieves an elongation at break of up to 1190% and exhibits a self-healing efficiency of 82% after 24 h. Moreover, supercapacitors assembled with this eutectogel electrolyte deliver an areal capacitance of 183 mF/cm 2 at a current density of 3 mA/cm 2 . This work provides a design strategy for the development of high-performance and durable energy storage devices, demonstrating significant potential for applications in flexible electronics and smart sensing systems.