3D Carbon Electrode with Hierarchical Nanostructure Based on NiCoP Core-Layered Double Hydroxide Shell for Supercapacitors and Hydrogen Evolution

Currently, the development of self-supported and low-cost earth-abundant electrocatalysts with well-defined nanostructure has shown significant potential in energy-related storage and electrocatalytic reactions. Herein, a three-dimensional (3D) self-supporting electrode NiCoP@NiCo LDH/CC (NCP@NCH/CC) constructed with NCP@NCH core-shell nanostructures and carbon cloth as substrate has been developed via the hydrothermal and subsequent electrodeposition process. The obtained 3D electrode with 1D NiCoP nanowires (NWs) core and 2D NiCo LDH nanosheets shell can exhibit superior electrochemical performance and remarkable stability for the pseudocapacitive reaction and hydrogen evolution reaction (HER), even comparable to the best reported transition metal phosphides (TMP) electrodes. It reveals an ultra-high area specific capacitance (9.4 F/cm(2) at 10 mA/cm(2) in 3 M KOH electrolyte), outstanding capacitance retention (74.12 % from 10 to 60 mA/cm(2)) and excellent cycling stability (93.51 % of original capacitance was retained after 5000 cycles at 50 mA/cm(2)) as supercapacitor electrode material. For HER in alkaline media, it can demonstrate an overpotential of 182 mV at 10 mA/cm(2) and Tafel slope of 82 mV/dec in 1 M KOH. For HER in acidic electrolyte, it can exhibit an overpotential of 141 mV at 10 mA/cm(2) and Tafel slope of 82 mV/dec in 0.5 M H2SO4. The electrochemical performance enhancement can be ascribed to the core-shell NiCoP@NiCo LDH nanostructure anchored on the carbon and synergistic effect with the carbon cloth in 3D electrode. Our present work provides a facile strategy to construct 3D TMP-based carbon electrode with core-shell nanostructures, demonstrating a great promise for storage processes and energy conversion.