Redox kinetics promoted by flower-like La2CoMnO6 @NiCo2O4 heterojunctions for high-performance supercapacitors

Abstract

The double perovskite oxide La2CoMnO6 (LCMO) is suitable for supercapacitor applications owing to its fast oxygen anion conduction and strong electron conductivity. However, the poor electron transfer of spinel oxide electrode materials weakens the intensity of surface redox reactions, thereby hindering the further improvement of energy density of the supercapacitors. In this study, flower-like heterogeneous La2CoMnO6 @NiCo2O4 materials were in-situ grown on a nickel foam (LCMO@NCO/Ni) via interface engineering and morphological engineering for the first time. The as-constructed heterogeneous materials benefit from the high electron conductivity of LCMO for the rapid transfer of electrons in NiCo2O4 (NCO), resulting in increased surface redox reaction rates. Interestingly, these successfully constructed heterogeneous LCMO and NCO structures act as electron donor and acceptor, respectively. Such a system promotes the increase in the electron cloud density around NCO, leading to an enhanced intensity of the redox reactions. The unique nanoflower-like structure and strong interfacial interaction of the developed heterogeneous LCMO@NCO/Ni material result in an electrode material with excellent supercapacitor performance with a high specific capacitance of 598 F·g−1 at a current density of 1 A·g−1. The asymmetric supercapacitor assembled with activated carbon and as-prepared material possesses a high energy density of 39.9 Wh·kg−1 at 1600 W·kg−1, proving suitable for practical applications. Overall, the proposed synthesis strategy is promising for the fabrication of novel heterogeneous electrode materials for supercapacitors with improved energy density.