Synthesis of Ni(OH)2 nanoflakes on ZnO nanowires by pulse electrodeposition for high-performance supercapacitors

•Ni(OH)2 nanoflakes are grown on ZnO nanowires by pulse electrodeposition.•The current on-time and off-time affect the size and interspacing of nanoflakes.•Well dispersed Ni(OH)2 nanoflakes facilitate the diffusion of electrolyte.•The ZnO/Ni(OH)2 nanocomposite electrode shows high Cs and good cycle-retention.

A high-performance supercapacitor based on Ni(OH)2 nanoflakes modified ZnO nanowires (NWs) was developed. The well-aligned ZnO NWs were synthesized by chemical bath deposition, followed by pulse electrodeposition of Ni(OH)2 nanoflakes on the surface of ZnO NWs at 1 mA cm−2 current density. The effects of the pulse electrodeposition conditions were systematically investigated. Both the pulse time and relaxation time were found to affect the size and interspacing of the nanoflakes, while the deposition cycle number determines the thickness of the Ni(OH)2 nanoflake shell. The ZnO/Ni(OH)2 nanocomposite electrode fabricated under the optimal pulse electrodeposition conditions has exhibited a large specific capacitance of 1830 F g−1, a high energy density of 51.5 Wh kg−1, and a high power density of 9 kW kg−1, revealing its potential application in electrochemical capacitors.

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