Controlled synthesis of porous spinet cobaltite core-shell microspheres as high-performance catalysts for rechargeable Li-O2 batteries

Rechargeable lithium-oxygen (Li-O-2) batteries are attracting much interest due to their highest energy density among chemical batteries. Recent studies have focused on designing highly efficient catalysts to improve the electrochemical performance of Li-O-2 batteries for long-term cycling. In this work, we report controlled synthesis of high efficient spinet catalysts in Li-O-2 batteries. The catalysts present core shell spheres, which are constructed by porous nano-plates. The remarkable feature of the hierarchical porous structure cannot only provide many electrocatalytic sites but also facilitate the flow of oxygen and infiltration of the electrolyte, and eventually improving the capacity and cyclability. As a representative catalyst, the synergistic effects of the inherited superior catalytic activity and the unique porous structure of NiCo2O4 lead to low overpotentials, high rate capacity as well as excellent long-term cyclability in Li-O-2 cells. This study affords a new strategy to achieve optimal performance in spinet catalysts, which may be extended to the preparation of other materials for a broad range of energy and environmental applications. (C) 2015 Elsevier Ltd. All rights reserved.