Facile fabrication of high performance zwitterionic P(NVP‐co‐SPE)/polyvinyl alcohol hydrogel polyelectrolyte for capacitor

Abstract

AbstractPolyelectrolyte hydrogel used for supercapacitors have the roles of both electrolyte and separator, the morphology and the strength of gel polyelectrolyte (GPE) are the keys for ionic transport properties therein. Here, the P(NVP‐co‐SPE)/polyvinyl alcohol (PVA) IPN hydrogel was prepared by photopolymerization and thermal polymerization, respectively. The influences of preparation method on morphology, mechanical strength and electrochemical performances were studied. Photopolymerized IPN GPE (UV‐GPE) exhibits a special regular microphase separation structure, and therefore has outstanding strength‐toughness and better electrochemical performance. The tensile strength and the toughness increased intensively from the 6.2 MPa and 3.4 MJ m−3 of thermal polymerized IPN GPE (TH‐GPE) to 28.5 MPa and 24.9 MJ m−3, respectively. The maximum swelling ratio of UV‐GPE is increased from 327% of TH‐GPE to 630%. The ionic conductivity of UV‐GPE increased from 4.29 × 10−2 S/cm of TH‐GPE to 5.82 × 10−2 S/cm. UV‐GPE has higher response current and specific capacitance. It also has the obviously better charge–discharge symmetry and cycling stability, and the capacity retention rate is still 92.3% after 1000 cycles. Thus, it brings out the fast, eco‐economic photopolymerization method is an effective way to prepare high‐performance polyelectrolyte hydrogel.