Robust quasi-solid-state integrated asymmetric flexible supercapacitors with interchangeable positive and negative electrode based on all-conducting-polymer electrodes

Flexible supercapacitors are promising flexible energy storage devices. However, manufacturing devices with high energy density, stable energy supply under harsh deformation, and more efficient modular application is still a challenge. Here, an all-gel-state integrated asymmetric flexible supercapacitor based on poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) and polypyrrole (PPy) composite hydrogel electrodes with an interchangeable positive and negative electrode was fabricated. The device has robust flexibility and mechanical durability, with an elongation at break of 286% at a tensile strength of 22.3 MPa and a capacitance retention rate of 98% after 1000 bending cycles, as well as fascinating electrochemical properties, with an energy density of 397.99 μWh cm−3 and a capacitance retention rate of 88.1% for 10,000 charges/discharge cycles. Moreover, the positive and negative electrodes of this asymmetric device can be used interchangeably, and it can power the light-emitting diodes (LEDs) without distinguishing between positive and negative. This design concept will perhaps open a new trend in the design of high-energy-density flexible energy storage devices.