High-Power and High-Energy-Density Flexible Pseudocapacitor Electrodes Made from Porous CuO Nanobelts and Single-Walled Carbon Nanotubes

We report a simple wet-chemical process to prepare porous CuO nanobelts (NBs) with high surface area and small crystal grains. These CuO NBs were mixed with carbon nanotubes in an appropriate ratio to fabricate pseudocapacitor electrodes with stable cycling performances, which showed a series of high energy densities at different power densities, for example, 130.2, 92, 44, 25, and 20.8 W h kg−1 at power densities of 1.25, 6.25, 25, and 50 k Wh kg−1, respectively. CuO-on-single-walled carbon nanotube (SWCNT) flexible hybrid electrodes were also fabricated using the SWCNT films as current collectors. These flexible electrodes showed much higher specific capacitance than that of electrodes made of pure SWCNTs and exhibited more stable cycling performance, for example, effective specific capacitances of >62 F g−1 for the hybrid electrodes after 1000 cycles in 1 M LiPF6/EC:DEC at a current density of 5 A g−1 and specific capacitance of only 23.6 F g−1 for pure SWCNT electrodes under the same testing condition.