Core–Shell‐Structured CNT@RuO 2 Composite as a High‐Performance Cathode Catalyst for Rechargeable Li–O 2 Batteries

A RuO 2 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–O 2 battery. This core–shell structure can effectively prevent direct contact between the CNT and the discharge product Li 2 O 2 , thus avoiding or reducing the formation of Li 2 CO 3 , 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 g total −1 . The battery also exhibited excellent rate and cycling performance.