Cattail spike-like Co(OH)F@Co3O4 nanoarrays for high-performance supercapacitors

Cattail spike-like Co(OH)F@Co3O4 nanoporous arrays were successfully prepared on nickel foam by hydrothermal method and calcination treatment. The Co(OH)F@Co3O4 nanoarrays, combining the advantages of the Co(OH)F and the Co3O4, exhibit ultrahigh structural stability and excellent electrochemical performance. The specific capacitance of Co(OH)F@Co3O4 is 543F g−1 at the current density of 1A g−1 and could maintain 88.34 % specific capacitance after 5000 cycles at 10 A g−1. Moreover, a two-electrode system assembled by Co(OH)F@Co3O4 and reduced graphene oxide exhibits a peak energy density of 30.155 Wh kg−1 at the power density of 800 W kg−1 and possesses an excellent cycling retention of 84.88 % after 5000 cycles at 10A g−1. These results indicate that the prepared Co(OH)F@Co3O4 composite is a promising positive electrode material for supercapacitors.