A core–shell structured design for enhanced supercapacitor performance: coating Ni(OH)2/Fe(OH)3 over NiMoO4 nanofibers

Abstract

This paper presents the development of a high-performance hydroxide-based supercapacitor electrode material, achieved through an innovative preparation strategy that integrates one-dimensional NiMoO₄ nanofibers with Ni(OH)₂/Fe(OH)₃ nanostructures, forming a NiMoO₄@Ni(OH)₂/Fe(OH)₃ composite electrode. This material boasts a high specific capacitance (1753 F g⁻¹ at 1 A g⁻¹) along with exceptional rate capability. The performance enhancement stems from synergies: Ni(OH)₂/Fe(OH)₃'s high surface area boosts charge storage and NiMoO₄ nanofibers stabilize the structure, preventing nanosheet agglomeration and preserving open spaces for ion diffusion. NiMoO₄'s conductivity aids electron transport, while Ni(OH)₂/Fe(OH)₃'s redox sites enhance charge storage, complementing each other for superior electrochemical performance. The asymmetric supercapacitor (ASC) device assembled from this composite achieved a high energy density of 324 W h kg⁻¹ at a power density of 33.33 W kg⁻¹, fully demonstrating the great potential of the NiMoO₄@Ni(OH)₂/Fe(OH)₃ composite in practical energy storage applications. The research provides new insights into enhancing the energy density, power density, and cycle life of supercapacitors, demonstrating significant potential for applications in the field of electrochemical energy storage.