Electrochemical performances of highly stretchable polyurethane (PU) supercapacitors based on nanocarbon materials composites

Stretchable polyurethane (PU) electrodes were fabricated via spray coating of reduced graphene oxide (rGO)/single wall carbon nanotubes (SWNTs) composite on gold-coated PU substrates. The symmetric PU supercapacitor was assembled by sandwiching poly (vinyl alcohol) (PVA)/phosphoric acid (H3PO4) gel polymer electrolyte between PU/rGO/SWNTs electrodes. Cyclic voltammetry (CV) showed rectangular curves indicating the retention of similar electric double layer capacitance even after repetitive stretching cycles. Electrochemical impedance spectroscopy (EIS) exhibited a well-defined capacitive behaviour with low internal resistance after prolonged stretching with 100% strain. Similarly, the galvanostatic charge/discharge test on up to 100 stretching cycles yielded symmetrical charge/discharge curves; indicating reversibility and facile kinetics of the device. The maximum capacitance of the unstretched PU supercapacitor was 43 F g(-1), which decreased to 31 F g(-1) after experiencing 100 cycles of stretching (72% retention). Moreover, the stretchable PU supercapacitor maintained 90% of its initial capacitance value at 100% elongation. (C) 2018 Elsevier B.V. All rights reserved.