Oxygen Redox Reaction in Ionic Liquid and Ionic Liquid-like Based Electrolytes: A Scanning Electrochemical Microscopy Study

Irene Ruggeri; Catia Arbizzani; Stefania Rapino; Francesca Soavi

doi:10.1021/acs.jpclett.9b00774

Oxygen Redox Reaction in Ionic Liquid and Ionic Liquid-like Based Electrolytes: A Scanning Electrochemical Microscopy Study

J Phys Chem Lett. 2019 Jun 20;10(12):3333-3338. doi: 10.1021/acs.jpclett.9b00774. Epub 2019 Jun 4.

Authors

Irene Ruggeri¹, Catia Arbizzani¹, Stefania Rapino¹, Francesca Soavi¹

Affiliation

¹ Department of Chemistry Giacomo Ciamician , Alma Mater Studiorum Bologna University , 40126 Bologna , Italy.

PMID: 31141369
DOI: 10.1021/acs.jpclett.9b00774

Abstract

Improving the stability of the cathode interface is one of the critical issues for the development of high-performance Li/O₂ batteries. The most critical feature to address is the development of electrolytes that mitigate side reactions that bring about cathode passivation. It is well-known that the superoxide anion (O₂^•-) plays a critical role. Here, we propose scanning electrochemical microscopy (SECM) as an analytical tool to screen the electrolyte of Li/O₂ batteries. We demonstrate that by using SECM it is possible to evaluate the stability of O₂^•- and of the cathode to the passivation process occurring during the oxygen redox reaction. Specifically, we report a study carried out at a glassy carbon electrode in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR₁₄TFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and in tetraethylene glycol dimethyl ether with LiTFSI, the latter ranging from the salt-in-solvent to solvent-in-salt regions.