Combining Accurate O2 and Li2O2 Assays to Separate Discharge and Charge Stability Limitations in Nonaqueous Li–O2 Batteries

TitleCombining Accurate O2 and Li2O2 Assays to Separate Discharge and Charge Stability Limitations in Nonaqueous Li–O2 Batteries
Publication TypeJournal Article
Year of Publication2013
AuthorsMcCloskey, Bryan D., Alexia Valery, Alan C. Luntz, Sanketh R. Gowda, Gregory M. Wallraff, Jeannette M. Garcia, Takashi Mori, and Leslie E. Krupp
JournalThe Journal of Physical Chemistry Letters
Volume4
Issue17
Pagination2989 - 2993
Date Published09/2013
ISSN1948-7185
Keywordscathode, decomposition, electrolyte, Li−air battery, peroxide, titration
Abstract

Li–air batteries have generated enormous interest as potential high specific energy alternatives to existing energy storage devices. However, Li–air batteries suffer from poor rechargeability caused by the instability of organic electrolytes and carbon cathodes. To understand and address this poor rechargeability, it is essential to elucidate the efficiency in which O2 is converted to Li2O2 (the desired discharge product) during discharge and the efficiency in which Li2O2 is oxidized back to O2 during charge. In this Letter, we combine many quantitative techniques, including a newly developed peroxide titration, to assign and quantify decomposition pathways occurring in cells employing a variety of solvents and cathodes. We find that Li2O2-induced electrolyte solvent and salt instabilities account for nearly all efficiency losses upon discharge, whereas both cathode and electrolyte instabilities are observed upon charge at high potentials.

DOI10.1021/jz401659f
Short TitleJ. Phys. Chem. Lett.
DOI10.1021/jz401659f