Soft, flexible and self-healable supramolecular conducting polymer-based hydrogel electrodes for flexible supercapacitors

Abstract

Conducting polymer-based hydrogels have drawn great attention recently as stretchable and soft electrode materials for flexible supercapacitors, for wearable electronics applications. In this work, we strategically combined a supramolecular approach and the ARGET–ATRP grafting methodology to prepare stretchable and self-healable poly(3,4-ethylenedioxythiophene) (PEDOT)-based conductive hydrogels with excellent electrochemical and mechanical properties. The supramolecular assembly of thiophene-3-boronic acid (ThBA) and poly(vinyl alcohol) (PVA), via dynamic boronate bonds, provides robustness for the PEDOT-based hydrogel. The hydrogen bonds between poly(acrylic acid) (PAA)-grafted-thiophene and PVA offer the fast self-healing properties to the hydrogel when exposed to mild pressures. After integrating the PAA-grafted-thiophene/PVA-based hydrogel with the self-healable, borate ester cross-linked PVA hydrogel electrolyte, the formed supercapacitor structure exhibits a specific capacitance of 222.32 mF cm⁻², with an energy density of 19.8 μW h cm⁻². The PEDOT-based hydrogel exhibits excellent electrochemical stability with 95.8% capacitance retention after 1000 charging–discharging cycles and a good capacitance recovery rate of 78.3% after the cutting–healing cycle. The utilisation of a supramolecular approach and the ARGET–ATRP grafting methodology could guide future developments in intrinsically stretchable and self-healable materials for wearable bioelectronics. The developed, intrinsically flexible and self-healable energy-storage device has potential for applications in the next generation of epidermal bioelectronics or other wearable electronics devices.