Core–Shell‐Structured CNT@RuO2 Composite as a High‐Performance Cathode Catalyst for Rechargeable Li–O2 Batteries

A RuO2 shell was uniformly coated on the surface of core CNTs by a simple sol-gel method, and the resulting composite was used as a catalyst in a rechargeable Li-O2 battery. This core-shell structure can effectively prevent direct contact between the CNT and the discharge product Li2 O2 , thus avoiding or reducing the formation of Li2 CO3 , which can induce large polarization and lead to charge failure. The battery showed a high round-trip efficiency (ca. 79 %), with discharge and charge overpotentials of 0.21 and 0.51 V, respectively, at a current of 100 mA gtotal (-1) . The battery also exhibited excellent rate and cycling performance.