Hierarchical nanoporous NiCoN nanoflowers with highly rough surface electrode material for high-performance asymmetric supercapacitors†

This study presents a novel strategy to enhance the energy storage performance of asymmetric supercapacitors (ASCs) by utilizing nanoporous NiCoN flower structures as the positive electrode material. The NiCoN material is synthesized via a straightforward hydrothermal method, followed by calcination in a nitrogen atmosphere. The resulting electrode demonstrates exceptional electrochemical properties, including a high specific capacity of 773 C g⁻¹ (1955 F g⁻¹), excellent rate capability, and outstanding cycling stability. The hierarchical architecture of the NiCoN electrode, composed of interconnected porous nanosheets, facilitates efficient charge transfer and enhanced electrolyte ion diffusion. When paired with activated carbon (AC) as the negative electrode in the NiCoN//AC ASC configuration, the device achieves an impressive energy density of 36 W h kg⁻¹ at a power density of 775 W kg⁻¹. Moreover, the device exhibits remarkable cycling stability, retaining 85% of its initial capacitance after 5000 charge–discharge cycles. These findings underscore the potential of NiCoN as a high-performance electrode material for ASCs, offering a promising pathway for advancements in next-generation energy storage technologies.