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Phosphoric acid and thermal treatments reveal the peculiar role of surface oxygen anions in lithium and manganese-rich layered oxides

He, Jiarong; Hua, Weibo; Missiul, Aleksandr; Melinte, Georgian; Das, Chittaranjan; Tayal, Akhil; Bergfeldt, Thomas; Mangold, Stefan; Liu, Xinyang; Binder, Joachim R.; Knapp, Michael; Ehrenberg, Helmut; Indris, Sylvio; Schwarz, Björn; Maibach, Julia

The interplay between cationic and anionic redox activity during electrochemical cycling makes layered Li-rich oxides appealing cathodes for state-of-the-art lithium-ion batteries. However, it remains challenging as the origin of lattice oxygen activity is not yet fully understood. Here we report on the effects of a lithium-deficient layer in the near-surface region of Co-free Li-rich Li[Li0.2Ni0.2Mn0.6]O-2 (LLNMO) achieved via a phosphoric acid surface treatment. Our results show that oxidized On- (0 < n < 2) species are formed on the surface of H3PO4-treated LLNMO resulting from Li ion deficiency and lattice distortion. The metastable On- could be easily released from the oxygen surface lattice forming O-2 via thermal treatment, accompanied by a surface reconstruction and a layered-to-rock-salt/spinel transition. The presented results demonstrate that the surface lattice structure plays a critical role in the electrochemical performance of LLNMO. This information provides new insights into the oxygen redox in LLNMO and opens up an opportunity for Li-rich cathodes to achieve long cycle life toward a broad range of applications in electrical energy storage devices.

Verlagsausgabe §
DOI: 10.5445/IR/1000126890
Veröffentlicht am 14.04.2021
DOI: 10.1039/D0TA07371G
Zitationen: 5
Web of Science
Zitationen: 5
Zitationen: 7
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Energiespeichersysteme (IAM-ESS)
Institut für Nanotechnologie (INT)
Karlsruhe Nano Micro Facility (KNMF)
Institut für Photonenforschung und Synchrotronstrahlung (IPS)
Helmholtz-Institut Ulm (HIU)
Institut für Angewandte Materialien (IAM)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 07.01.2021
Sprache Englisch
Identifikator ISSN: 2050-7488, 2050-7496
KITopen-ID: 1000126890
HGF-Programm 37.01.15 (POF III, LK 01) Reaction and Degradation Mechanisms
Weitere HGF-Programme 56.12.11 (POF IV, LK 01) Materials - Quantum, Complex and Functional
Erschienen in Journal of materials chemistry / A
Verlag Royal Society of Chemistry (RSC)
Band 9
Heft 1
Seiten 264–273
Vorab online veröffentlicht am 30.09.2020
Schlagwörter 2020-025-029691, TEM, FIB
Nachgewiesen in Web of Science
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