Spinel-structured CuCo2O4 with a mixed 1D/2D morphology for asymmetric supercapacitor and oxygen evolution electrocatalyst applications

Abstract

Transition metal oxides with multifunctional properties have attracted attention for use in various electro-catalytic applications, but their weak electroactive centers have severely limited their commercialization. In the present study, we describe an efficient bifunctional material whose structural morphology makes it both an effective oxygen evolution reaction (OER) electrocatalyst and a reliable power source for supercapacitor (SC) electrodes. We successfully fabricated spinel-structured CuCo2O4 consisting of a mix of one-dimensional (1D) nanorods and two-dimensional (2D) nanoplates using precipitation followed by hydrothermal treatment and calcination. For comparison purposes, CuO nanoplates and Co3O4 nanorods were synthesized individually, and their multifunctional features were examined. The synthesized mixed-morphology CuCo2O4 delivered an excellent electrochemical performance for SC and OER electrocatalyst applications. The mixed-morphology CuCo2O4 produced a specific capacity of 561 C g−1 (1122 F g−1) at 1 A g−1 and exhibited a superior rate capability and excellent stability, with 92% retention of capacity after 5000 cycles at 30 A g−1 in a three-electrode cell. In addition, a fabricated asymmetric supercapacitor device (CuCo2O4//activated carbon) delivered an energy density of 47.6 W h kg−1 and a power density of 1280 W kg−1, with outstanding long-term cyclic stability. Furthermore, the prepared CuCo2O4 had a low Tafel slope, a high electrochemical surface area, and excellent long-term durability. Therefore, mixed-morphology CuCo2O4 holds significant promise for use in SC and OER catalyst applications. Moreover, this study offers a useful method for preparing multifunctional materials.