Electrodeposition preparation of NiCo2O4 mesoporous film on ultrafine nickel wire for flexible asymmetric supercapacitors

Mesoporous NiCo2O4 was directly coated on an ultrafine nickel wire to fabricate a battery-type electrode through a facile process comprising electrodeposition of Ni/Co/Zn alloy, dealloying, and oxidation. The binder-free electrode with flexible features delivers a high specific capacity of 315.4 C g−1 and excellent cycling performance (retention after 50,000 cycles). An assembled asymmetric supercapacitor containing NiCo2O4/ultrafine nickel wire with Fe3O4/ultrafine nickel wire shows high energy density of 32.6 Wh kg−1, high power density of 35,000 W kg−1, and 94.8% retention of initial capacity after 20,000 cycles. This work proposes a simple design and facile process for fabrication of practical flexible energy storage devices. © 2018 Elsevier B.V.