Ruthenium-Functionalized Hierarchical Carbon Nanocages as Efficient Catalysts for Li-O₂ Batteries

Developing an efficient cathode is essential to obtain high rate capability and rechargeable lithium oxygen (Li-O₂) batteries. Herein, ruthenium (Ru)-functionalized hierarchical carbon nanocages (hCNCs) are synthesized and employed as a cathode catalyst for Li-O₂ batteries. The as-prepared cathode exhibits high discharge capacity, low charge potential (8135 mA h g⁻¹ with 3.85 V charge potential at a current density of 0.08 mA cm⁻²), outstanding rate capability (3416 mA h g⁻¹ at a current density of 0.48 mA cm⁻²) and good stability up to 78 cycles at a limited capacity of 500 mA h g⁻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⁺/O₂ mass transport, and the high catalytic activity of Ru nanoparticles.