--- res: bibo_abstract: - Aprotic sodium–O2 batteries require the reversible formation/dissolution of sodium superoxide (NaO2) on cycling. Poor cycle life has been associated with parasitic chemistry caused by the reactivity of electrolyte and electrode with NaO2, a strong nucleophile and base. Its reactivity can, however, not consistently explain the side reactions and irreversibility. Herein we show that singlet oxygen (1O2) forms at all stages of cycling and that it is a main driver for parasitic chemistry. It was detected in‐ and ex‐situ via a 1O2 trap that selectively and rapidly forms a stable adduct with 1O2. The 1O2 formation mechanism involves proton‐mediated superoxide disproportionation on discharge, rest, and charge below ca. 3.3 V, and direct electrochemical 1O2 evolution above ca. 3.3 V. Trace water, which is needed for high capacities also drives parasitic chemistry. Controlling the highly reactive singlet oxygen is thus crucial for achieving highly reversible cell operation.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Lukas foaf_name: Schafzahl, Lukas foaf_surname: Schafzahl - foaf_Person: foaf_givenName: Nika foaf_name: Mahne, Nika foaf_surname: Mahne - foaf_Person: foaf_givenName: Bettina foaf_name: Schafzahl, Bettina foaf_surname: Schafzahl - foaf_Person: foaf_givenName: Martin foaf_name: Wilkening, Martin foaf_surname: Wilkening - foaf_Person: foaf_givenName: Christian foaf_name: Slugovc, Christian foaf_surname: Slugovc - foaf_Person: foaf_givenName: Sergey M. foaf_name: Borisov, Sergey M. foaf_surname: Borisov - foaf_Person: foaf_givenName: Stefan Alexander foaf_name: Freunberger, Stefan Alexander foaf_surname: Freunberger foaf_workInfoHomepage: http://www.librecat.org/personId=A8CA28E6-CE23-11E9-AD2D-EC27E6697425 orcid: 0000-0003-2902-5319 bibo_doi: 10.1002/anie.201709351 bibo_issue: '49' bibo_volume: 56 dct_date: 2017^xs_gYear dct_isPartOf: - http://id.crossref.org/issn/1433-7851 dct_language: eng dct_publisher: Wiley@ dct_title: Singlet oxygen during cycling of the aprotic sodium-O2 battery@ ...