Highly Strong and Tough Double-Crosslinked Hydrogel Electrolyte for Flexible Supercapacitors

Excellent mechanical properties are indispensable for the wide application of supercapacitors and various wearable devices. In this article, a novel double-crosslinked hydrogel electrolyte (DC-GPE) is prepared by the combination of the hydrophobic association of acrylamide with the amphiphilic monomer AEO-9-AC and the ionic complexation of acrylic acid with Fe3+ for the first time by a two-step method. Owing to the dual energy dissipation network, the DC-GPE exhibits an excellent tensile strength of up to 3.1 MPa, an elongation at break of more than 900 % and a toughness of 18.1 MJ m(-3), which is far beyond the currently reported hydrogel electrolyte. Moreover, the ionic conductivity of the DC-GPE achieves as high as 40.1 mS cm(-1), which is 3 times higher than the corresponding LiClO4 solution electrolyte (12.3 mS cm(-1)). Besides, the activated carbon-based supercapacitor assembled by the DC-GPE shows excellent electrochemical performance, which is superior to most activated carbon-based supercapacitors. These results demonstrate that the DC-GPE shows a great application prospect in wearable devices like supercapacitors. Significantly, the new dual physical cross-linking strategy improves the contradiction between the strength and the toughness of the gel electrolyte materials. And provides a new solution for preparing high-strength as well as high-toughness gel electrolyte.