Facile synthesis of hierarchical NiCoP nanowires@NiCoP nanosheets core–shell nanoarrays for high-performance asymmetrical supercapacitor

Transition metal phosphides have been regarded as reliable supercapacitor electrode materials and extensively researched. In this work, a facile three-step way has been taken to synthesize NiCoP@NiCoP core–shell nanoarrays directly grown on carbon cloth, which was used as a high-performance supercapacitor electrode. Compared with the NiCo-LDH precursor and NiCoP nanowire and NiCoP nanosheet, NiCoP@NiCoP core–shell composite shows higher electrochemical performance owing to the integration of the advantages of phosphides and core–shell structure. To be specific, the as-fabricated NiCoP C–S electrode exhibits great electrochemical performance with high specific capacitance (1492.5 F g−1 at 1 A g−1), good rate performance (68.82% of the initial specific capacitance at 15 A g−1) and outstanding cycling stability (maintains 80.9% of the initial capacitances after 5000 cycles at 10 A g−1). Moreover, the assembled NiCoP C–S//rGO asymmetric supercapacitor device delivers a high energy density of 48.13 Wh kg−1 at the power density of 1125 W kg−1 and it still retains 20.94 Wh kg−1 at a high power density of 11250 W kg−1, indicating its great possibility of practical application.