Engineering NiCoP arrays by cross-linked nanowires and nanosheets as advanced materials for hybrid supercapacitors

摘要

In this work, the NiCoP nanoarrays were synthesized on Ni foam through the hydrothermal method and phosphating process. As an electrode material of supercapacitor, NiCoP/NF nanoarrays show excellent performance with a high specific capacitance of 2564 F g(-1) at 2 A g(-1), unexpected charge-discharge rate performance, and slow self-discharge behavior, which are superior to those of single metal phosphides (CoP/NF and NiP/NF). More importantly, the hybrid supercapacitor NiCoP/NF//graphene possesses a specific energy of 22.8 Wh kg(-1) and good cycle stability that the capacitance remains 68.33% of the initial specific capacitance after 4000 cycles. The improvement in electrochemical performance mostly stems from the three-dimensional heterostructure, the positive synergistic combination of Ni and Co metal elements in the electrochemical process, and the high conductivity of phosphides. Therefore, this work demonstrates the potential of NiCoP/NF electrodes in supercapacitor energy storage.