Hierarchical mesoporous Co3O4@ZnCo2O4 hybrid nanowire arrays supported on Ni foam for high-performance asymmetric supercapacitors

Abstract

In this paper, hierarchical mesoporous Co3O4@ZnCo2O4 hybrid nanowire arrays (NWAs) on Ni foam were prepared through a two-step hydrothermal process associated with successive annealing treatment. The Co3O4@ZnCo2O4 hybrid NWAs exhibited excellent electrochemical performances with a high specific capacity of 1,240.5 C g−1 at a current density of 2 mA cm−2, with rate capability of 59.0% shifting from 2 to 30 mA cm−2, and only a 9.1% loss of its capacity even after 3,000 cycles at a consistent current density of 10 mA cm−2. An asymmetric supercapacitor (Co3O4@ZnCo2O4 NWAs||activated carbon) was fabricated and exhibited a high specific capacity of 168 C g−1 at a current density of 1 A g−1. And a preferable energy density of 37.3 W h kg−1 at a power density of 800 W kg−1 was obtained. The excellent electrochemical performances indicate the promising potential application of the hierarchical mesoporous Co3O4@ZnCo2O4 hybrid NWAs in energy storage field.