Sodium Alginate/Zwitterionic Polymer Gel Electrolyte for Integrated All‐Solid‐State Supercapacitors

Abstract All‐solid‐state stretchable supercapacitors (SSSCs) have attracted widespread attention in the wearable and medical fields because of their nontoxic, safe, and environmentally friendly characteristics. In this paper, a dual network hydrogel polymer was synthesized by a one‐pot method, which was constructed from sodium alginate (SA) and zwitterion copolymer of acrylamide (AM) and sulfobetaine methacrylate (SBMA). The dual network hydrogel polymerSA_m/P(AM‐co‐SBMA (SAS_m for short) were immersed in 1 M H₂SO₄ electrolyte to obtain gel polymer electrolytes (GPEs). Stretchable electrodes were synthesized on the matrix of SAS_m gels. Non‐integrated all‐solid‐state stretchable supercapacitors (non‐integrated SSSCs), integrated all‐solid‐state supercapacitors (SSCs) and integrated SSSCs were all assembled into the ‘sandwich’ structure. The elongation of the integrated SSSC is the best and reaches 280 %, and its areal capacitance is 1.96 mF/cm² under a current destiny of 50 μA/cm², and the capacitance still remains 95 % of the initial value after 10000 charge and discharge cycles, and its energy density is 5.8×10⁻² μWh/cm² at a power density of 2.9×10⁻² mW/cm². This integrated SSSC has excellent cycling stability while maintaining good tensile properties.