Reaction and transport in Ag/Ag2O gas diffusion electrodes of aqueous Li–O2 batteries: Experiments and modeling

• We model aqueous lithium–oxygen batteries.
• Multiphase-flow in porous gas diffusion electrodes is important.
• We perform half-cell experiments for validation and parameterization.
• We identify rate-limiting processes via sensitivity analysis.

Aqueous lithium–oxygen batteries are promising candidates for electric energy storage. In this paper we present and discuss a multiphase continuum model of an aqueous lithium–oxygen single cell including reactions and transport in a porous gas diffusion electrode (GDE). The model is parameterized using in-house half-cell experiments and available literature data on aqueous electrolytes. We validate our transport model with cyclic voltammetry and electrochemical impedance spectroscopy measurements over a wide range of temperatures (25, 40, 55 °C) and electrolyte concentrations (0.1–2 M). We observe very good agreement between simulations and measurements during oxygen reduction conditions. A sensitivity analysis of the validated model demonstrates the influence of the porous structure on GDE performance and gives directions for the future development of electrodes.