Regensburg 2022 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 13: Materials for Storage and Conversion of Energy (joint session MM/KFM)

KFM 13.2: Vortrag

Dienstag, 6. September 2022, 10:30–10:45, H46

Oxygen Hole Formation Controls Stability in LiNiO2 Cathodes: DFT Studies of Oxygen Loss and Singlet Oxygen Formation in Li-Ion Batteries — •Annalena Genreith-Schriever1,3, Hrishit Banerjee1,2,3, Clare P. Grey1,3, and Andrew J. Morris2,31Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom — 2School of Metallurgy and Materials, University of Birmingham, Birmingham, United Kingdom — 3The Faraday Institution, Harwell Science and Innovation Campus, Didcot, United Kingdom

Ni-rich cathode materials achieve both high voltages and capacities in Li-ion batteries but are prone to structural instabilities and oxygen loss via the formation of singlet oxygen. Using ab initio molecular dynamics simulations, we observe spontaneous O2 loss from the (012) surface of delithiated LiNiO2, singlet oxygen forming in the process. We find that the origin of the instability lies in the pronounced oxidation of O during delithiation, i.e., O plays a central role in Ni-O redox in LiNiO2, as analysed with density-functional theory and dynamical mean-field theory calculations based on maximally localised Wannier functions. The O2 loss route observed here consists of 2 surface O.− radicals combining to form a peroxide ion, which is oxidised to O2, leaving behind 2 O vacancies and 2 O2− ions: effectively 4 O.− radicals disproportionate to O2 and 2 O2− ions. Singlet oxygen formation is caused by the singlet ground state of the peroxide ion, with spin conservation dictating the preferential release of 1O2.

100% | Mobil-Ansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2022 > Regensburg