@article{14687, abstract = {The short history of research on Li-O2 batteries has seen a remarkable number of mechanistic U-turns over the years. From the initial use of carbonate electrolytes, that were then found to be entirely unsuitable, to the belief that (su)peroxide was solely responsible for degradation, before the more reactive singlet oxygen was found to form, to the hypothesis that capacity depends on a competing surface/solution mechanism before a practically exclusive solution mechanism was identified. Herein, we argue for an ever-fresh look at the reported data without bias towards supposedly established explanations. We explain how the latest findings on rate and capacity limits, as well as the origin of side reactions, are connected via the disproportionation (DISP) step in the (dis)charge mechanism. Therefrom, directions emerge for the design of electrolytes and mediators on how to suppress side reactions and to enable high rate and high reversible capacity.}, author = {Jethwa, Rajesh B and Mondal, Soumyadip and Pant, Bhargavi and Freunberger, Stefan Alexander}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, publisher = {Wiley}, title = {{To DISP or not? The far‐reaching reaction mechanisms underpinning Lithium‐air batteries}}, doi = {10.1002/anie.202316476}, year = {2023}, } @article{14701, author = {Archer, Lynden A. and Bruce, Peter G. and Calvo, Ernesto J. and Dewar, Daniel and Ellison, James H. J. and Freunberger, Stefan Alexander and Gao, Xiangwen and Hardwick, Laurence J. and Horwitz, Gabriela and Janek, Jürgen and Johnson, Lee R. and Jordan, Jack W. and Matsuda, Shoichi and Menkin, Svetlana and Mondal, Soumyadip and Qiu, Qianyuan and Samarakoon, Thukshan and Temprano, Israel and Uosaki, Kohei and Vailaya, Ganesh and Wachsman, Eric D. and Wu, Yiying and Ye, Shen}, issn = {1364-5498}, journal = {Faraday Discussions}, keywords = {Physical and Theoretical Chemistry}, publisher = {Royal Society of Chemistry}, title = {{Towards practical metal–oxygen batteries: General discussion}}, doi = {10.1039/d3fd90062b}, year = {2023}, } @article{14702, author = {Attard, Gary A. and Calvo, Ernesto J. and Curtiss, Larry A. and Dewar, Daniel and Ellison, James H. J. and Gao, Xiangwen and Grey, Clare P. and Hardwick, Laurence J. and Horwitz, Gabriela and Janek, Juergen and Johnson, Lee R. and Jordan, Jack W. and Matsuda, Shoichi and Mondal, Soumyadip and Neale, Alex R. and Ortiz-Vitoriano, Nagore and Temprano, Israel and Vailaya, Ganesh and Wachsman, Eric D. and Wang, Hsien-Hau and Wu, Yiying and Ye, Shen}, issn = {1364-5498}, journal = {Faraday Discussions}, keywords = {Physical and Theoretical Chemistry}, publisher = {Royal Society of Chemistry}, title = {{Materials for stable metal–oxygen battery cathodes: general discussion}}, doi = {10.1039/d3fd90059b}, year = {2023}, } @article{13044, abstract = {Singlet oxygen (1O2) formation is now recognised as a key aspect of non-aqueous oxygen redox chemistry. For identifying 1O2, chemical trapping via 9,10-dimethylanthracene (DMA) to form the endoperoxide (DMA-O2) has become the mainstay method due to its sensitivity, selectivity, and ease of use. While DMA has been shown to be selective for 1O2, rather than forming DMA-O2 with a wide variety of potentially reactive O-containing species, false positives might hypothetically be obtained in the presence of previously overlooked species. Here, we first give unequivocal direct spectroscopic proof by the 1O2-specific near infrared (NIR) emission at 1270 nm for the previously proposed 1O2 formation pathways, which centre around superoxide disproportionation. We then show that peroxocarbonates, common intermediates in metal-O2 and metal carbonate electrochemistry, do not produce false-positive DMA-O2. Moreover, we identify a previously unreported 1O2-forming pathway through the reaction of CO2 with superoxide. Overall, we give unequivocal proof for 1O2 formation in non-aqueous oxygen redox and show that chemical trapping with DMA is a reliable method to assess 1O2 formation.}, author = {Mondal, Soumyadip and Jethwa, Rajesh B and Pant, Bhargavi and Hauschild, Robert and Freunberger, Stefan Alexander}, issn = {1364-5498}, journal = {Faraday Discussions}, keywords = {Physical and Theoretical Chemistry}, publisher = {Royal Society of Chemistry}, title = {{Singlet oxygen in non-aqueous oxygen redox: Direct spectroscopic evidence for formation pathways and reliability of chemical probes}}, doi = {10.1039/d3fd00088e}, year = {2023}, } @article{12065, abstract = {Capacity, rate performance, and cycle life of aprotic Li–O2 batteries critically depend on reversible electrodeposition of Li2O2. Current understanding states surface-adsorbed versus solvated LiO2 controls Li2O2 growth as surface film or as large particles. Herein, we show that Li2O2 forms across a wide range of electrolytes, carbons, and current densities as particles via solution-mediated LiO2 disproportionation, bringing into question the prevalence of any surface growth under practical conditions. We describe a unified O2 reduction mechanism, which can explain all found capacity relations and Li2O2 morphologies with exclusive solution discharge. Determining particle morphology and achievable capacities are species mobilities, true areal rate, and the degree of LiO2 association in solution. Capacity is conclusively limited by mass transport through the tortuous Li2O2 rather than electron transport through a passivating Li2O2 film. Provided that species mobilities and surface growth are high, high capacities are also achieved with weakly solvating electrolytes, which were previously considered prototypical for low capacity via surface growth.}, author = {Prehal, Christian and Mondal, Soumyadip and Lovicar, Ludek and Freunberger, Stefan Alexander}, issn = {2380-8195}, journal = {ACS Energy Letters}, number = {9}, pages = {3112--3119}, publisher = {American Chemical Society}, title = {{Exclusive solution discharge in Li-O₂ batteries?}}, doi = {10.1021/acsenergylett.2c01711}, volume = {7}, year = {2022}, }