Flexible Hybrid Membranes with Ni(OH)₂ Nanoplatelets Vertically Grown on Electrospun Carbon Nanofibers for High-Performance Supercapacitors

The practical applications of transition metal oxides and hydroxides for supercapacitors are restricted by their intrinsic poor conductivity, large volumetric expansion, and rapid capacitance fading upon cycling, which can be solved by optimizing these materials to nanostructures and confining them within conductive carbonaceous frameworks. In this work, flexible hybrid membranes with ultrathin Ni­(OH)₂ nanoplatelets vertically and uniformly anchored on the electrospun carbon nanofibers (CNF) have been facilely prepared as electrode materials for supercapacitors. The Ni­(OH)₂/CNF hybrid membranes with three-dimensional macroporous architectures as well as hierarchical nanostructures can provide open and continuous channels for rapid diffusion of electrolyte to access the electrochemically active Ni­(OH)₂ nanoplatelets. Moreover, the carbon nanofiber can act both as a conductive core to provide efficient transport of electrons for fast Faradaic redox reactions of the Ni­(OH)₂ sheath, and as a buffering matrix to mitigate the local volumetric expansion/contraction upon long-term cycling. As a consequence, the optimized Ni­(OH)₂/CNF hybrid membrane exhibits a high specific capacitance of 2523 F g^–1 (based on the mass of Ni­(OH)₂, that is 701 F g^–1 based on the total mass) at a scan rate of 5 mV s^–1. The Ni­(OH)₂/CNF hybrid membranes with high mechanical flexibility, superior electrical conductivity, and remarkably improved electrochemical capacitance are condsidered as promising flexible electrode materials for high-performance supercapacitors