Growth of urchin-like ZnCo2O4 microspheres on nickel foam as a binder-free electrode for high-performance supercapacitor and methanol electro-oxidation

The spinel-type transition metal oxides play key role in realizing cost-effective energy storage systems by exhibiting outstanding electrochemical activity and stability. Free standing 3D hierarchical mesoporous ZnCo2O4 microspheres are grown on nickel foam (NF) substrate using hydrothermal route followed by annealing treatment. 3D hierarchical mesoporous ZnCo2O4 microspheres with high surface area and uniform mesoporous distribution exhibits high electrochemical performance. The ZnCo2O4/NF electrode material deliver superior specific capacitance of 1143 F g(-1) at a current density of 1.25 A g(-1) in aqueous 2 M KOH solution and exhibits long-term cycling stability with specific capacitance of 880 F g(-1) after 6000 cycles at 12.5 A g(-1). Furthermore, ZnCo2O4/NF electrode maintains current density upto 105 A g-1 in 1 M KOH mixed with 0.5 M methanol when applied as electro-catalyst for methanol electro-oxidation. The high electrochemical performance is mainly attributed to faster ion/electron transfer and an enhanced electrochemical kinetics. The present simple, and cost-effective synthesis approach can open new era for large-scale applications of the novel materials for different electrochemical applications. (C) 2017 Elsevier Ltd. All rights reserved.