Li-O2 kinetic overpotentials: Tafel plots from experiment and first-principles theory

V. Viswanathan, J. K. Nørskov, A. Speidel, R. Scheffler, S. Gowda, A. C. Luntz*

*Corresponding author for this work

Research output: Contribution to journalLetterResearchpeer-review

Abstract

We report the current dependence of the fundamental kinetic overpotentials for Li-O2 discharge and charge (Tafel plots) that define the optimal cycle efficiency in a Li-air battery. Comparison of the unusual experimental Tafel plots obtained in a bulk electrolysis cell with those obtained by first-principles theory is semiquantitative. The kinetic overpotentials for any practical current density are very small, considerably less than polarization losses due to iR drops from the cell impedance in Li-O2 batteries. If only the kinetic overpotentials were present, then a discharge-charge voltaic cycle efficiency of ∼85% should be possible at ∼10 mA/cm2 superficial current density in a battery of ∼0.1 m2 total cathode area. We therefore suggest that minimizing the cell impedance is a more important problem than minimizing the kinetic overpotentials to develop higher current Li-air batteries.

Original languageEnglish
JournalJournal of Physical Chemistry Letters
Volume4
Issue number4
Pages (from-to)556-560
Number of pages5
ISSN1948-7185
DOIs
Publication statusPublished - 2013

Cite this

Viswanathan, V., Nørskov, J. K., Speidel, A., Scheffler, R., Gowda, S., & Luntz, A. C. (2013). Li-O2 kinetic overpotentials: Tafel plots from experiment and first-principles theory. Journal of Physical Chemistry Letters, 4(4), 556-560. https://doi.org/10.1021/jz400019y