Substantial oxygen loss and chemical expansion in lithium-rich layered oxides at moderate delithiation.

Autor: Csernica PM; Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA., McColl K; Department of Chemistry, University of Bath, Bath, UK., Busse GM; Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA., Lim K; Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA., Rivera DF; Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA., Shapiro DA; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA., Islam MS; Department of Materials, University of Oxford, Oxford, UK. saiful.islam@materials.ox.ac.uk., Chueh WC; Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. wchueh@stanford.edu.; Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. wchueh@stanford.edu.
Jazyk: angličtina
Zdroj: Nature materials [Nat Mater] 2024 Oct 17. Date of Electronic Publication: 2024 Oct 17.
DOI: 10.1038/s41563-024-02032-6
Abstrakt: Delithiation of layered oxide electrodes triggers irreversible oxygen loss, one of the primary degradation modes in lithium-ion batteries. However, the delithiation-dependent mechanisms of oxygen loss remain poorly understood. Here we investigate the oxygen non-stoichiometry in Li 1.18-x Ni 0.21 Mn 0.53 Co 0.08 O 2-δ electrodes as a function of Li content by using cycling protocols with long open-circuit voltage steps at varying states of charge. Surprisingly, we observe substantial oxygen loss even at moderate delithiation, corresponding to 2.5, 4.0 and 7.6 ml O 2 per gram of Li 1.18-x Ni 0.21 Mn 0.53 Co 0.08 O 2-δ after resting at upper capacity cut-offs of 135, 200 and 265 mAh g -1 for 100 h. Our observations suggest an intrinsic oxygen instability consistent with predictions of high oxygen activity at intermediate potentials versus Li/Li + . In addition, we observe a large chemical expansion coefficient with respect to oxygen non-stoichiometry, which is about three times greater than those of classical oxygen-deficient materials such as fluorite and perovskite oxides. Our work challenges the conventional wisdom that deep delithiation is a necessary condition for oxygen loss in layered oxide electrodes and highlights the importance of calendar ageing for investigating oxygen stability.
(© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)
Databáze: MEDLINE
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