Hybrid architecture design enhances the areal capacity and cycling life of low-overpotential nanoarray oxygen electrode for lithium–oxygen batteries

Abstract

Abstract Transition metal oxide (TMO) nanoarrays are promising architecture designs for self-supporting oxygen electrodes to achieve high catalytic activities in lithium-oxygen (Li−O2) batteries. However, the poor conductive nature of TMOs and the confined growth of nanostructures on the limited surfaces of electrode substrates result in the low areal capacities of TMO nanoarray electrodes, which seriously deteriorates the intrinsically high energy densities of Li−O2 batteries. Herein, we propose a hybrid nanoarray architecture design that integrates the high electronic conductivity of carbon nanoflakes (CNFs) and the high catalytic activity of Co3O4 nanosheets on carbon cloth (CC). Due to the synergistic effect of two differently featured components, the hybrid nanoarrays (Co3O4−CNF@CC) achieve a high reversible capacity of 3.14 mA h cm−2 that cannot be achieved by only single components. Further, CNFs grown on CC induce the three-dimensionally distributed growth of ultrafine Co3O4 nanosheets to enable the efficient utilization of catalysts. Thus, with the high catalytic efficiency, hybrid Co3O4−CNF@CC also achieves a more prolonged cycling life than pristine TMO nanoarrays. The present work provides a new strategy for improving the performance of nanoarray oxygen electrodes via the hybrid architecture design that integrates the intrinsic properties of each component and induces the three-dimensional distribution of catalysts.