Cu(I)/Cu(II) partially substituting the Co(II) of spinel Co3O4 nanowires with 3D interconnected architecture on carbon cloth for high-performance flexible solid-state supercapacitors

The 3D interconnected architecture nanowires of Co3O4 partially substituted by Cu(I)/Cu(II) coated on the carbon cloth (CCO@CC) with high specific surface area were fabricated by a facile and low-cost hydrothermal approach and consequent thermal annealing. The prepared binder-free CCO@CC electrode exhibits high specific capacitance (1947.2 F g(-1) or 973.6 C g(-1) at 1 A g(-1)) and superior cyclic stability (93.76% retention of initial value up to 10,000 cycles). In addition, the CCO@CC and synthesized Fe2O3@CC are used as positive and negative electrodes in the presence of PVA-KOH as a gel electrolyte to assemble a flexible solid-state asymmetric supercapacitor. The as-assembled flexible device shows a high specific capacitance of 182.7 F g(-1), high energy density of 57.1 W h kg(-1) at the power density of 749.75 W kg(-1), remarkable cyclic stability with 93.25% retention after 10,000 cycles and almost no capacity loss under different bending angles. Therefore, this material has potential application for wearable electronics with the excellent mechanical flexibility.