Wrinkled Polypyrrole Aggregates Grown on Elastic Polymers as Electrodes for High-Performance Stretchable Supercapacitors

Attaching electroactive polymer on elastomer is a facile way to construct a stretchable electrode, but maintaining the interface robustness of the heterogeneous components remains a challenge. Herein, porous polypyrrole (PPy) is firmly fixed on elastic poly(hydroxyethyl acrylate)- co -poly( N -hydroxyethyl acrylamide) (PHEA- co -PHEAA) by two-stage polymerization to prepare a stretchable electrode PPy@PHEA- co -PHEAA. The first-stage polymerization of PPy is performed in a PHEA- co -PHEAA hydrogel, and the second one is performed on the surface of prestrained PHEA- co -PHEAA in the presence of surfactant sodium dodecyl sulfate (SDS) self-assembly. Micro wrinkles consisting of globular PPy aggregates are constructed on the electrode surface to adapt the elongation by unfolding. The firm fixation of PPy on PHEA- co -PHEAA ensures the interconnected globular PPy aggregate is well preserved under stretch conditions. PPy@PHEA- co -PHEAA exhibits an electrical conductivity of 81.5 S cm –1 and a stretchability of 293%. The supercapacitor assembled from PPy@PHEA- co -PHEAA and an acid hydrogel electrolyte delivers a specific capacitance of 1003 mF cm –2 and a capacitance retention of 89.4% after 2000 stretch–release cycles at a strain of 100%. Embedding electroactive aggregates in elastic substrates by sequential polymerization offers a general strategy to construct stretchable electrodes for wearable supercapacitors.