Superior Rechargeability and Efficiency of Lithium-Oxygen Batteries: Hierarchical Air Electrode Architecture Combined with a Soluble Catalyst

Abstract

The lithium-oxygen battery has the potential to deliver extremely high energy densities; however, the practical use of Li-O2 batteries has been restricted because of their poor cyclability and low energy efficiency. In this work, we report a novel Li-O2 battery with high reversibility and good energy efficiency using a soluble catalyst combined with a hierarchical nanoporous air electrode. Through the porous three-dimensional network of the air electrode, not only lithium ions and oxygen but also soluble catalysts can be rapidly transported, enabling ultra-efficient electrode reactions and significantly enhanced catalytic activity. The novel Li-O2 battery, combining an ideal air electrode and a soluble catalyst, can deliver a high reversible capacity (1000 mAh g-1) up to 900 cycles with reduced polarization (about 0.25 V). Outstanding storage performance: A lithium-oxygen battery that uses a soluble catalyst combined with a hierarchical nanoporous air electrode shows high reversibility and good energy efficiency. Through the porous three-dimensional network of the air electrode, not only lithium ions and oxygen but also soluble catalysts can be rapidly transported, enabling significantly enhanced catalytic activity (CNT=carbon nanotube). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.