Protocols for Evaluating and Reporting Li-O2 Cell Performance

The lithium oxygen system, if fully harnessed in the form of a rechargeable battery, offers a tantalizing ideal energy density of 3445 W h L^–1, more than doubling state-of-the-art Li ion technology.  An impressive amount of recent research has attacked this system, and despite its complexity, there now exists a menagerie of different rechargeable Li–O₂ battery chemistries and electrode architectures exhibiting some level of promise. However, the system still presents a multitude of unsolved fundamental issues, mostly related to the electrochemical stability of the cathode, electrolyte, and Li metal anode in the exceptionally harsh cell environment, which are often specific to the exact combination of materials utilized. A natural consequence is that drawing comparisons between different Li–O₂ battery configurations is intrinsically very difficult.