Decoupled bifunctional air electrodes for high-performance hybrid lithium-air batteries

Lithium-air batteries have become appealing in recent years, but one of the major challenges is the large overpotential associated with the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Tremendous efforts have been made on developing highly active and durable catalysts to lower the overpotentials for ORR and OER. In addition to the intrinsic activity and stability of the catalysts, construction of the air electrodes plays an important role in the overall performance of the air electrodes. Accordingly, three kinds of electrode configurations are herein compared: single, combined, and decoupled bifunctional air electrodes. The decoupled design of the air electrodes shows the best performance in terms of both the discharge and charge performance compared to the other configurations. (C) 2014 Elsevier Ltd. All rights reserved.