Highly stretchable reduced graphene oxide (rGO)/single-walled carbon nanotubes (SWNTs) electrodes for energy storage devices

• Spray coating was used to prepare stretchable and flexible reduced graphene oxide (rGO)/single-walled carbon nanotubes (SWNTs) electrodes.
• Unstretched rGO/SWNTs electrode showed 265 F g−1 of capacitance value and decreased to 162 Fg−1 after 100 stretching cycles (61% retention).
• The rGO/SWNTs electrode was maintained at 75% of its initial capacitance under constant 100% strain.
• Approximately 65% of the initial capacitance for the rGO/SWNTs composite electrode was retained after 100 stretching cycles and then maintained up to the 3000th CV cycle.

We report on the fabrication of reduced graphene oxide/single-walled carbon nanotubes (rGO/SWNTs) electrodes deposited onto stretchable polyurethane via spray coating. The electrochemical properties of the rGO/SWNTs electrodes were compared to pure rGO and SWNT electrodes. The highest capacitance value obtained for the unstretched rGO/SWNTs electrode was 265 F g−1 in 1 M H2SO4 at 5 mV s−1, which decreased to 219 and 162 F g−1 after 50 and 100 stretching cycles (at 100% strain), respectively. The rGO/SWNTs composite electrode also retained approximately 75% of its initial capacitance under constant 100% strain. Further characterization, including galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy (EIS), showed that the rGO/SWNTs electrode retained a well-defined capacitive response after repetitive stretching to 100% strain. Overall, the rGO/SWNTs composite electrode showed enhanced electrochemical properties in comparison to rGO and SWNTs electrodes. Approximately 65% of the initial capacitance for the rGO/SWNTs composite electrode is retained after 100 stretching cycles and then maintained up to the 3000th CV cycle, making the electrodes a potential option for stretchable energy storage applications.