Moss-like nickel-cobalt phosphide nanostructures for highly flexible all-solid-state hybrid supercapacitors with excellent electrochemical performances

Abstract Energy storage devices with high security, stability and flexibility are desirable for newly smart wearable electronics. Herein, the moss-like nickel cobalt bimetallic phosphides (Ni-Co-P) nanosheet arrays on carbon fabrics are rationally designed and synthesized, which are directly treated as the electrodes to assemble highly flexible all-solid-state hybrid supercapacitors. The synthesized Ni-Co-P nanosheet arrays exhibit outstanding electrochemical performance and excellent stability owing to architectural advantages and compositional synergistic effect, which are further theoretically supported by calculations with density functional theory (DFT). The as-assembled hybrid supercapacitors deliver a high energy density of 48.4 Wh kg−1 at 811.2 W kg−1 accompanying a satisfactory cyclic stability (about 88.8 % retention after 8000 cycles). What's more, there is no obvious decline for the capacitance after bending 1,000 times under different bending states, implying excellent flexibility and mechanical stability of these bio-inspired nanosheet arrays. The outstanding mechanical stability and electrochemical performance demonstrate the promising potential of the hybrid supercapacitor as energy storage devices.