3D web freestanding RuO-CoO nanowires on Ni foam as highly efficient cathode catalysts for Li-O batteries.

The mechanism of Li-O batteries is based on the reactions of lithium ions and oxygen, which hold a theoretical higher energy density of approximately 3500 W h kg. In order to improve the practical specific capacity and cycling performance of Li-O batteries, a catalytically active mechanically robust air cathode is required. In this work, we synthesized a freestanding catalytic cathode with RuO decorated 3D web CoO nanowires on nickel foam. When the specific capacity was limited at 500 mA h g, the RuO-CoO/NiF had a stable cycling life of up to 122 times. The outstanding performance can be primarily attributed to the robust freestanding CoO nanowires with RuO loading. The unique 3D web nanowire structure provides a large surface for LiO growth and RuO nanoparticle loading, and the RuO nanoparticles help to promote the round trip deposition and decomposition of LiO, therefore enhancing the cycling behavior. This result indicates the superiority of RuO-CoO/NiF as a freestanding highly efficient catalytic cathode for Li-O batteries.