Ruthenium-Functionalized Hierarchical Carbon Nanocages As Efficient Catalysts for Li-O-2 Batteries

Developing an efficient cathode is essential to obtain high rate capability and rechargeable lithium oxygen (Li-O-2) batteries. Herein, ruthenium (Ru)-functionalized hierarchical carbon nanocages (hCNCs) are synthesized and employed as a cathode catalyst for Li-O-2 batteries. The as-prepared cathode exhibits high discharge capacity, low charge potential (8135 mAhg(-1) with 3.85V charge potential at a current density of 0.08 mAcm(-2)), outstanding rate capability (3416 mAhg(-1) at a current density of 0.48 mAcm(-2)) and good stability up to 78 cycles at a limited capacity of 500 mAhg(-1). Such excellent battery performance is ascribed to the synergistic effect of the interconnected hierarchically porous structure of hCNCs, which can facilitate effective electrolyte immersion and efficient Li+/O-2 mass transport, and the high catalytic activity of Ru nanoparticles.