Journal article
An Electrochemical Impedance Spectroscopy Investigation of the Overpotentials in Li−O2 Batteries
Department of Energy Conversion and Storage, Technical University of Denmark1
Atomic Scale Materials Modelling, Department of Energy Conversion and Storage, Technical University of Denmark2
IBM Research3
Applied Electrochemistry, Department of Energy Conversion and Storage, Technical University of Denmark4
Haldor Topsoe AS5
Lithium−O2 (Li−O2) batteries are currently limited by a large charge overpotential at practically relevant current densities, and the origin of this overpotential has been heavily debated in the literature. This paper presents a series of electrochemical impedance measurements suggesting that the increase in charge potential is not caused by an increase in the internal resistance.
It is proposed that the potential shift is instead dictated by a mixed potential of parasitic reactions and Li2O2 oxidation. The measurements also confirm that the rapid potential loss near the end of discharge (“sudden death”) is explained by an increase in the charge transport resistance. The findings confirm that our theory and conclusions in ref 1, based on experiments on smooth small-area glassy carbon cathodes, are equally valid in real Li−O2 batteries with porous cathodes.
The parameter variations performed in this paper are used to develop the understanding of the electrochemical impedance, which will be important for further improvement of the Li−air battery.
Language: | English |
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Year: | 2015 |
Pages: | 4039-4047 |
ISSN: | 19448252 and 19448244 |
Types: | Journal article |
DOI: | 10.1021/am5083254 |
ORCIDs: | Hjelm, Johan , Vegge, Tejs and Norby, Poul |