Facile fabrication of large-area hybrid Ni-Co hydroxide/Cu(OH)2/copper foam composites

Abstract In this work, we have developed a versatile method for hybrid Ni–Co hydroxide array fabricated on copper foam (CF). Starting from commercial copper foam, the process involves sequential solution immersion and electrolytic deposition steps, both of which are simple and rapid to carry out and potentially scalable. The resulting Ni–Co hydroxide/Cu(OH) 2 /CF has a hierarchical and the nanoarray has a hollow structure, and exhibits outstanding electrochemical performance as battery-type electrode material for hybrid supercapacitors with excellent specific capacity (849.6 C g −1 , at 5 mA cm −2 ) and good cycling stability (81.03% of its initial capacity value was preserved after 5000 charge/discharge cycles at 100 mA cm −2 ). Furthermore, an asymmetric supercapacitor was fabricated with the Ni-Co hydroxide/Cu(OH) 2 /CF as positive electrode while the rGO as negative electrode. The hybrid device exhibits excellent energy density of 58.61 Wh kg −1 at a power density of 359.33 W kg −1 . Furthermore, we demonstrated that the process is also scalable in practice, by fabricating a large-size (20 cm × 30 cm) Ni–Co hydroxide/Cu(OH) 2 /CF which retains excellent specific capacity.