NiCo2O4/MnO2 core/shell arrays as a binder-free catalytic cathode for high-performance lithium-oxygen cells

Lithium-oxygen (or Li-air) cells have attracted increasing interest in recent years due to their extremely high theoretical energy density. A reasonable design of the catalytic cathode is essential to realize a high performance of Li-O-2 cells. In this work, a unique core-shell MnO2@NiCo2O4 array cathode with a porous structure has been deposited directly on carbon cloth by a facile hydrothermal route. The array structure facilitates electrode wetting and oxygen gas transportation. The porous structure supplies free space for Li2O2 loading. The MnO2@NiCo2O4 array cathode exhibits a high catalytic effect enabling the conformal growth of Li2O2 with the array structure retained. This growth behavior of Li2O2 makes the decomposition of Li2O2 easy upon charging. Li-O-2 cells with the MnO2@NiCo2O4 cathode can sustain a stable cycling of 168 cycles with a limited capacity of 500 mA h g(-1) at 400 mA g(-1), which is superior to those with the NiCo2O4 cathode.