Commercialization of lithium-oxygen batteries faces many challenges, such as electrolyte decomposition, short cycle life, low energy and power density, and high cell mass. However, the commercialization of LiO2 batteries for aeronautics is more challenging due to additional safety constraints on cyclability and performance (high specific-power and specific-energy). In this paper, we perform experiments and use the results to calibrate a 1-D finite element model to simulate discharge profiles up to 5 mA cm-2. The calibrated model is used to perform parametric studies of geometrical, microstructural, transport, and material properties for different discharge times, and discharge current densities. Next, a simulation-based optimization study shows optimal cell designs for various electrolytes for high specific-power. Results show that a high specific-power LiO2 cell needs to have a cathode with a thickness equal to oxygen diffusion length, thin separator, optimized anode, and other components with low mass. The specific-power is sensitive to discharge time, discharge current density, and microstructural and geometrical properties. Also, in some cases, electrolytes with high oxygen solubility or high external partial pressure can compensate for electrolytes with low oxygen diffusivity. However, reducing the cell mass is the most straight forward path to improving specific-power.

Electrochemical plating of Li metal on the graphite electrode is the key limitation behind slow charging times of Li-ion batteries (LIBs) in electric vehicles (EVs). Currently, electrochemical methods to detect the onset of Li plating while a battery is fast charging are sparse. In this study, we use operando electrochemical impedance spectroscopy to reliably detect the onset of Li plating on graphite electrodes in three-electrode LIBs. An increase in the graphite solid-electrolyte interface (SEI) resistance indicates that Li plating has occurred. By cross-validating with a highly sensitive ex situ chemical titration, we determine that this technique can detect very small amounts of plated Li (<0.6% of the graphite electrode's capacity). We also offer physical explanations for the observed impedance behavior. Finally, we show that this technique can be applied to standard two-electrode LIB systems, making the method an important step toward safely implementing fast charging protocols for LIBs in EVs.