Zwitterionic semi-IPN electrolyte with high ionic conductivity and high modulus achieving flexible 2.4 V aqueous supercapacitors

Polymer electrolytes (PEs) have the widespread interest for solid-state supercapacitors. As an ideal PEs, it is requested to possess high ionic conductivity, high electrolyte content, and excellent mechanical properties. Here, we present the zwitterionic semi-interpenetrating polymeric network electrolytes (ZSIPNEs) that enable achieving ultra-high ionic conductivity and excellent mechanical properties. ZSIPNEs are synthesis by interpenetrating various content of poly(sulfobetaine methacrylate) (pSBMA) into zwitterionic polymer (ZP) matrix, being simply prepared by 17 m NaClO4_(aq) intake. At content of pSBMA of 0.1%, ZS-0.1 possesses the ultra-high ionic conductivity of 135.2 mScm⁻¹ at 25 °C. In addition, ZS-0.1 shows excellent mechanical properties, including the compressive strength of 0.36 MPa, compressive strain of 74.5%, compressive modulus of 33.7 kPa, and toughness of 4.329 Jm⁻³. Furthermore, the electrochemical performances of electrolytes are studied using carbon-based supercapacitors which are assembled with 17 m NaClO4_(aq) (C-aq), ZS-0 (C-ZPE), and ZS-0.1 (C-ZSIPNE), being evaluated by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge. C-ZSIPNE shows the wide electrochemical window of 2.4 V and the superior electrochemical performance by delivering high energy density of 83.6Whkg⁻¹, and high power density of 19.1kWkg⁻¹. Under bending angles of 90°, the capacitance of C-ZSIPNE keeps at almost 100%, being potential application in flexible supercapacitors. 3 brief informative subheadings: Zwitterionic polymer electrolyte, Semi-interpenetrating polymeric network, High performance supercapacitors Background: Polymer electrolytes (PEs) have the widespread interest for solid-state supercapacitors. As an ideal PEs, it is requested to possess high ionic conductivity, high electrolyte content, and excellent mechanical properties. Methods: The ionic conductivity of PE was evaluated by electrochemical impedance spectroscopy. The mechanical properties of PE were evaluated by compressive strain-stress curve. The electrochemical properties of PE were evaluated by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge. Significant Findings: ZSIPNEs enable achieving ultra-high ionic conductivity of 135.2 mScm⁻¹ and excellent mechanical properties (compressive modulus of 33.7 kPa). C-ZSIPNE shows the wide electrochemical window of 2.4 V and the superior electrochemical performance by delivering high energy density of 83.6Whkg⁻¹, and high power density of 19.1kWkg⁻¹. Under bending angles of 90°, the capacitance of C-ZSIPNE keeps at almost 100%, being potential application in flexible supercapacitors.