A facile preparation of Nickel Foam-supported Ni(OH)2 nano arrays via in-situ etching method with superior bendable electrochemical performance for wearable power supply

Abstract In this paper, the new Ni(OH)2 array is synthesized by a facile method in which the nickel ions are generated by the intercrystaline corrosion of nickel foam in HCl–NH4Cl complex solution, and grow in situ to form an ordered nano Ni(OH)2 array via the complexation reactions of Ni2+-NH3 by precise control of pH value. Scanning electron microscope, Mapping and X-ray diffraction tests show that its nanosheets with 8–10 nm in thickness and 150–200 nm in width. Electrochemical tests indicate that Ni(OH)2 provides a specific capacity of 319.6 mAh g−1 at extremely heavy load of 200 A g−1 which benefits from the good electrical conductivity between the in-situ grow Ni(OH)2 and the nickel crystals of nickel foam. The composite offers very low decay rate of 2.8% during super long cycling of 100,000 cycles at 100 A g−1, demonstrating excellent durability at ultrahigh rate. Furthermore, the material exhibits very good bendability and maintains a specific capacity retention of 93% after bending 100 times due to its special ordered array grow in intercrystalline interfaces of nickel foam. All tests prove the new composite is a promising material for the next generation electric vehicles and wearable devices.