High-performance asymmetric supercapacitors using optimized coral-type-Ni3S2​/NiCu layered double hydroxide hierarchical nanostructures on nickel foam

The depletion of fossil energy resources has accelerated the global pursuit of renewable energy storage solutions. Supercapacitors (SCs) have gained prominence due to their high power density, fast charge-discharge rates, and long cycle life. In this study, we develop optimized coral-type nickel sulfide (Ni₃S₂)/nickel-copper layered double hydroxide (NiCu LDH) nanostructures on nickel foam (NF) via electrochemical anodization, cathodic deposition, and a modified solvothermal method for high-performance asymmetric supercapacitors (ASCs). Physical and chemical characterizations confirm the successful incorporation of Ni₃S₂ and NiCu LDH, revealing a well-defined crystalline structure, uniform morphology, and consistent elemental distribution. Ni₃S₂ provides excellent electrical conductivity and structural stability, addressing the limitations of NiCu LDH. The coral-like Ni₃S₂ and NiCu LDH hierarchical nanostructures enhance porosity and surface area, contributing to superior electrochemical properties. The composite electrode exhibits a specific capacitance of 8.80 F∙cm⁻² and 204 F∙cm⁻³ at 1 mA, demonstrating excellent cycling stability and improved charge transfer kinetics. The assembled NF/Ni₃S₂/NiCuLDH//AC/NF ASC device demonstrates a specific energy of 27.34 Wh∙kg⁻¹ and specific power of 126.67 W∙kg⁻¹ at 5 mA, making it a promising candidate for advanced energy storage applications. This study provides valuable insights into the design and optimization of hierarchical composite materials for enhanced energy storage.