Among many cathode materials explored for lithium-oxygen cathode, carbons are often used because they help achieve high discharge capacities and good ORR performance.  However, most lithium-oxygen batteries containing carbon electrodes suffer from a low round-trip efficiency, low rate capability, a poor cycle life, and electrolyte instability. In this poster, we report a binder- and carbon-free, 3D porous Ru and RuO₂ foam cathode for lithium-oxygen batteries. The cathode was simply fabricated by three-step process; co-electrodeposition, electrochemical dealloying and heat treatment process. Both 3D porous Ru and RuO₂ dendritic foams have lots of cavity and pits which provide a large surface area for catalytic sites and buffer spaces for the morphological volume stress by the formation/decomposition of Li₂O₂ during the cycling process. Moreover, both dendritic foams provide a facile electron pathway, a short ion diffusion length, a rapid transport channel for oxygen and electrolytes, and numerous catalytic sites for high electrochemical performance. 3D porous Ru and RuO₂ foam cathode delivers a discharge capacity of 1570 mAh/g and 4900 mAh/g at 50 mA/g and can be recharged for OER under low charge voltage with good reversibility and cyclability. We systematically investigated the reversibility and cyclability of a lithium-oxygen battery using the 3D porous Ru/RuO₂ foam cathode using scanning electron microscopy (SEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), in-situ Differential Electrochemical Mass Spectrometry (DEMS) and FT-IR spectroscopy. The results using the 3D porous nanostructured electrodes in our study represent a promising approach for high-performance electrodes which are compatible with scaled-up manufacturing process for next-generation lithium- air batteries due to their simple and rapid fabrication process.