Morphologically engineered mixed metal oxides on carbon fibers as a binder-free electrode for diffusion capacitance-dominated hybrid supercapacitors
摘要
Engineering the morphology of spinel mixed metal oxides is a critical strategy for developing high-performance hybrid supercapacitors as they enhance both energy storage performance and cyclic stability. Herein, we present a simple, binder-free method to fabricate hierarchical, pineapple-like CuCo2O4 nanostructures on carbon fibers via low-temperature wet-chemical method. By utilizing a combination of hexamine and urea, we tailored the morphology and crystallinity of CuCo2O4, improving ion accessibility and interconnectivity, which led to superior electrochemical performance compared to individual components. Particularly, the pineapple-like CuCo2O4 demonstrated diffusion-dominated behavior, achieving a higher specific capacitance of 745 F g−1 at 1 A g−1 and excellent cycling stability. Moreover, a hybrid supercapacitor was fabricated using diffusion-type CuCo2O4 electrode and activated carbon as the capacitive electrode, which exhibited good synergy in delivering excellent energy storage performance. The device achieved a specific capacity of 140.5 C g−1 at 0.5 A g−1 and an energy density of 45.5 Wh kg−1 with a high-power density of 5950 W kg−1. Even at a high current density of 10 A g−1, the hybrid supercapacitor maintained excellent rate capability and remarkable cycling stability (89.6% retention after 10,000 cycles), demonstrating efficient charge storage and transfer. Benefiting from high voltage and energy density, the fabricated hybrid supercapacitors successfully powered various LEDs, illustrating their potential for real-world applications. Our work demonstrates the importance of spinal-type nanostructure engineering to achieve enhanced electrochemical performance, providing a straightforward pathway for developing next-generation supercapacitors and battery materials.
Graphical abstract