Self-adhesive frost-resistant conductive hydrogel electrolytes based on TA@WSCA-Zn autocatalytic system for flexible and foldable solid-state capacitors

Abstract

In this study, we have successfully prepared a freeze-resistant conductive hydrogel with a fast polymerization rate and excellent mechanical and adhesive properties. In this paper, hydrogels capable of rapid polymerization in a short time were prepared based on the TA@WSCA-Zn (WSCA, water-soluble cellulose acetate; TA@WSCA, tannic acid-coated WSCA suspension; TA@WSCA-Zn, a certain amount of zinc chloride (ZnCl2) was added to TA@WSCA suspension;) autocatalytic system at room temperature or low temperature. TA@WSCA-Zn forms a stable reversible quinone-catechol redox reaction to activate the decomposition of ammonium persulfate (APS, initiator) to produce SO4−· radicals, which triggers the ultra-fast polymerization of amphoteric ([2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl), SBMA) and acrylic monomers (AA). To improve the frost resistance and electrical conductivity of the hydrogels, we also introduced amphoteric ions, which can provide migration channels for Zn2+ and greatly increase the migration rate. The TA@WSCA-7.5/PSA hydrogel (PSA, hydrogel prepared by polymerization of acrylic acid and SBMA as monomers;) can achieve tensile strength and toughness of 1.33 MPa and 4.89 MJ m−3. It can provide excellent electrical conductivity and interfacial adhesion over a temperature range of 25 to −60 °C. In addition, the supercapacitor assembled from the TA@WSCA-7.5/PSA hydrogel electrolyte still has good capacitance characteristics after folding and 10,000 charge/discharge cycles, with a capacitance retention of 93.33 % and an excellent cycle life. This autocatalytic system provides a new strategy and approach for the preparation of freeze-resistant conductive hydrogel electrolytes.