Journal article
The role of transition metal interfaces on the electronic transport in lithium–air batteries
Department of Physics, Technical University of Denmark1
Stanford University2
Computational Atomic-scale Materials Design, Department of Physics, Technical University of Denmark3
Nano-Microstructures in Materials, Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark4
Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark5
Risø National Laboratory for Sustainable Energy, Technical University of Denmark6
Low electronic conduction is expected to be a main limiting factor in the performance of reversible lithium–air, Li–O2, batteries. Here, we apply density functional theory and non-equilibrium Green's function calculations to determine the electronic transport through lithium peroxide, Li2O2, formed at the cathode during battery discharge.
We find the transport to depend on the orientation and lattice matching of the insulator–metal interface in the presence of Au and Pt catalysts. Bulk lithium vacancies are found to be available and mobile under battery charging conditions, and found to pin the Fermi level at the top of the anti bonding peroxide π*(2px) and π*(2py) levels in the Li2O2 valence band.
Under an applied bias, this can result in a reduced transmission, since the anti bonding σ*(2pz) level in the Li2O2 conduction band is found to couple strongly to the metal substrate and create localized interface states with poor coupling to the Li2O2 bulk states. These observations provide a possible explanation for the higher overpotential observed for charging than discharge.
Language: | English |
---|---|
Year: | 2011 |
Pages: | 2-9 |
ISSN: | 18734308 and 09205861 |
Types: | Journal article |
DOI: | 10.1016/j.cattod.2010.12.022 |
ORCIDs: | Thygesen, Kristian Sommer , Nørskov, Jens Kehlet and Vegge, Tejs |