The reduced graphene oxide/single-wall carbon nanotubes composites are coated onto the polyurethane substrate using spray coating technique to produce a stretchable and semi-transparent supercapacitor. The electrochemical properties of the stretchable and semi-transparent full device as a function of stretching cycles are characterized using electrochemical impedance spectroscopy (EIS), cyclic voltammetry and galvanostatic charge/discharge tests. The EIS and charge/discharge curves of the stretchable and semi-transparent supercapacitor exhibit good capacitive behavior even after prolonged stretching cycles up to 100. The highest capacitance value of the stretchable and semi-transparent supercapacitor (unbent) is 21.4 F g−1. The capacitance value of the stretchable and semi-transparent supercapacitor is retained 62% after 100th stretching with application of 3000th galvanostatic charge/discharge cycles.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Preparation of stretchable polymer electrolyte
        2.3 Preparation of reduced graphene oxide (rGO)single-wall carbon nanotubes (SWNTs) composite dispersion
        2.4 Fabrication of semi-transparent and stretchable polyurethane (PU) substrate
        2.5 Fabrication of semi-transparent and stretchable rGOSWNTs composite electrode
        2.6 Preparation of semi-transparent and stretchable polyurethane (PU) full device
    3 Characterization
        3.1 Cyclic voltammetry (CV)
        3.2 Electrochemical impedance spectroscopy (EIS)
        3.3 Charge and discharge measurement
        3.4 Morphology study of the rGO and rGOSWNTs composite
    4 Results and discussion
    5 Conclusion
    References

• Hyeon Taek Jeong(Division of Energy and Environmental Engineering, Daejin University)