Tensile-endurable nanolayered polypyrrole templated by liquid crystal for high-performance stretchable supercapacitors

Abstract

Ordered architectures favorable for energy storage are hard to build and preserve on stretchable electrodes owing to the elongation-induced variation in morphology. Herein, we demonstrate the construction of nanolayered polypyrrole (PPy) on stretchable polymeric electrodes via lyotropic liquid crystal (LLC) template for the first time. In situ graft polymerization of PPy onto swollen polyacrylamide-co-poly(2-hydroxy ethyl acrylate) in an aqueous Lα LLC gives stretchable electrodes with nanolayered PPy rooted in expandable wrinkles. The nanolayered PPy electrode could be stretched up to 330 % strain and keep intact after 2,000 stretch-release cycles owing to reversible unfolding of wrinkles. By virtue of the well-arranged PPy nanolayers, the stretchable electrode exhibits a high electrical conductivity of 154 S cm−1 and gives a capacitance of 1143 mF cm−2 after assembled into a supercapacitor with H2SO4 polyacrylamide hydrogel. In addition, the capacitance retention remains 94.6 % after 2,000 stretch-release cycles accompanied by galvanostatic charge–discharge. The LLC templating graft polymerization of conjugated polymers on elastic substrates paves a way to develop nanostructured stretchable electrodes for high-performance wearable supercapacitors.