Engineering the grain boundary: a promising strategy to configure NiCoP 4 O 12 /NiCoP nanowire arrays for ultra-stable supercapacitor

NiCoP 4 O 12 /NiCoP nanorod-like arrays with tunable grain boundary density and pores were synthesized by the processes composed of hydrothermal and pyrolysis, in which, the electron structure of Ni and Co atoms characterized by X-ray photoelectron spectroscopy was contemporaneous inverse manipulated. The optimized NiCoP 4 O 12 /NiCoP arrays have a high specific capacitance of 507.8 µAh·cm −2 at 1 mA·cm −2 , and good rate ability of 64.7% retention at 30-folds increased current density. Importantly, an ultra-stable ability, 88.5% of retention after 10000 cycles, was achieved in an asymmetric cell assembled of the NiCoP 4 O 12 /NiCoP arrays with activated carbon. In addition, the energy and power densities of an asymmetric cell were higher than those of other work, demonstrating as-prepared NiCoP 4 O 12 /NiCoP arrays are promising electrodes for supercapacitors.