Highly Deformable Graphene/Poly(3,4-ethylenedioxythiophene):Poly(styrene Sulfonate) Hydrogel Composite Film for Stretchable Supercapacitors

Graphene films have been extensively applied in supercapacitors owing to their high electrical conductivity and good mechanical strength; however, their application in stretchable supercapacitors is still hampered by their low elastic deformation ability. Herein, hybridizing graphene with the hydrogel of a conductive polymer (PEDOT:PSS) endows graphene films with substantially improved ductility. The resultant graphene-conductive polymer hydrogel composite film (GCPH) can be stretched to as long as 114.6% of its original length. Meanwhile, it possesses a much higher specific capacitance (28.52 F g–1) than that of the pure graphene film, as the PEDOT:PSS hydrogel prevents graphene from restacking. A proof-of-concept all-gel-state planar supercapacitor based on GCPH film electrodes is fabricated, which exhibits excellent electrochemical performance under a stretching state. The device shows no significant capacitance decline even when it is stretched to 220% of its original length (20% more than the pre-strain limit), and it maintains 98.23% of its initial capacitance after repeated stretching–releasing cycles.