Thanks to their high theoretical specific energy densities, Li-air batteries are attracting increasing attention as a potentially transformative energy storage technology. However, despite this potential, Li-air technology remains in its infancy, and attaining a viable secondary Li-air battery will require that several challenges be overcome. To accelerate the development Li-air batteries, we employ DFT calculations to elucidate performance-limiting phenomena. Our work addresses the surface and bulk thermodynamics of Li-O discharge phases, and predicting mass transport limitations in Li2O2. Regarding surfaces, we find that the stable facets of Li2O2 are half-metallic, even though bulk Li2O2 is an insulator. In contrast, Li2O surfaces are insulating. These distinct surface properties may explain the reversibility of systems in which Li2O2 is the discharge product, and the irreversibility of those that discharge to Li2O. Regarding bulk properties, we find that Li vacancies mediate diffusion in Li2O2, and discuss connections between mass transport and charging overpotentials.

Revealing performance-limiting phenomena in Li-air batteries via first-principles simulation

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.