Design and Fabrication of an All-Solid-State Polymer Supercapacitor with Highly Mechanical Flexibility Based on Polypyrrole Hydrogel

A conducting polymer-based hydrogel (PPy/CPH) with a polypyrrole-poly(vinyl alcohol) interpenetrating network was prepared by utilization of a chemical cross-linked poly(vinyl alcohol)-H2SO4 hydrogel (CPH) film as flexible substrate followed by vapor-phase polymerization of pyrrole. Then an all-solid-state polymer supercapacitor (ASSPS) was fabricated by sandwiching the CPH film between two pieces of the PPy/CPH film. The ASSPS is mechanically robust and flexible with a tensile strength of 20.83 MPa and a break elongation of 377% which is superior to other flexible conducting polymer hydrogel-based supercapacitors owing to the strong hydrogen bonding interactions among the layers and the high mechanical properties of the PPy/CPH. It exhibits maximum volumetric specific capacitance of 13.06 F/cm3 and energy density of 1160.9 μWh/cm3. The specific capacitance maintains 97.9% and 86.3% of its initial value after 10 000 folding cycles and 10 000 charge-discharge cycles, respectively. The remarkable electrochemical and mechanical performance indicates this novel ASSPS device is promising for flexible electronics.