Ru-decorated knitted Co3O4 nanowires as a robust carbon/binder-free catalytic cathode for lithium–oxygen batteries

Abstract

The working principle of Li–air (Li–O₂) batteries is based on the formation/decomposition of Li₂O₂ on the catalytic electrode, which is basically different from the shuttle mechanism of Li-ion batteries. The successful operation of Li–O₂ batteries requires an optimized cathode that is electrochemically/chemically stable, mechanically robust, and catalytically active. In this work, we proposed a unique design of a binder/carbon-free catalytic cathode consisting of knitted Co₃O₄ nanowires and decorated Ru nanoparticles. It was found that the Co₃O₄/Ru-catalyzed Li–O₂ batteries exhibit considerably higher capacity and much improved cycling performance than the Co₃O₄-catalyzed ones. When the capacity is limited at 500 mA h g⁻¹, the Co₃O₄/Ru-catalyzed battery can sustain a stable cycling of 29 times. The stable cycling can last 122 times at a limited capacity of 300 mA h g⁻¹. This result indicates that the catalytic performance and structural stability of the cathodes are equally important to achieve a high performance of Li–O₂ batteries.