Ru-Embedded Highly Porous Carbon Nanocubes Derived from Metal-Organic Frameworks for Catalyzing Reversible Li2O2 Formation.

Rechargeable lithium-oxygen batteries (LOBs) have attracted increasing attention due to their high energy density but highly rely on the development of efficient oxygen catalysts for reversible Li2O2 deposition/decomposition. Herein, highly porous carbon nanocubes with a specific surface area up to 1600 m2 g-1 are synthesized and utilized to tightly anchor Ru nanoparticles for using as the oxygen-cathode catalyst in LOBs, achieving a low charge/discharge potential gap of only 0.75 V, a high total discharge capacity of 17,632 mA h g-1, and a superb cycling performance of 550 cycles at 1000 mA g-1. Comprehensive ex situ and operando characterizations unravel that the outstanding LOB performance is ascribed to the highly porous catalyst structure embedding rich active sites that synergistically function in reducing overpotentials, suppressing parasitic reactions, accommodating reaction products, and promoting mass and charge transportation.