Nickel vanadium sulfide grown on nickel copper phosphide Dendrites/Cu fibers for fabrication of all-solid-state wire-type micro-supercapacitors

Herein, we have successfully fabricated NiVS/NiCuP nanostructures on Cu wire as a fiber electrode for high performance FSMSCs applications. The 3D NiCuP dendritic film was firstly deposited on Cu wire through the electrodeposition method, which not only act as a scaffold for deposition of the electroactive materials (NiV-LDH and NiV-S), but also served as a micro-porous current collector, supplied extra capacitances. Then, NiV-LDH nanosheets grown on 3D NiCuP film were obtained using a hydrothermal method. The sulfidation of NiV-LDH is carried out through an ion-exchange reaction of OH- with S2- to obtain NiVS, which maintains an ultrathin and porous structure, improves the electrical conductivity and reduces the diffusion resistance of the electrode. The as-prepared c-NiVS/NiCuP/CW electrode exhibits outstanding specific capacitance (13.4 F cm(-2), 1.7 F cm(-1), 1342.28 F cm(-3) at a current density of 4 mA cm(-2)) compared with the pristine NiV-LDH and NiVS directly growing on Cu wire in the absence of 3D NiCuP film. Finally, a solid state asymmetric fiber-shaped microsupercapacitor (FSAMSCs) is fabricated using c-NiVS/NiCuP/CW as the positive electrode and rGO/CF as the negative electrode. The assembled FSMSC device has a maximum operational voltage of 1.8 V and presented a high energy density of 295 mu Wh cm(-2) (22.7 mWh cm(-3) and 46.35 mu Wh cm(-1)) at a power density of 4.3 mW cm(-2) (330.7 mW cm(-3) and 674.7 mu W cm(-1)) with an excellent cycling stability (91.5% of its initial specific capacitance after 3000 cycles) and good mechanical stability. These results suggest that the fabricated device has excellent potential as a power source for next generation flexible and portable fiber-based energy storage microdevices.