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DOI: 10.1021/acs.jpcc.7b06598

Charge Transfer-Induced Lattice Collapse in Ni-Rich NCM Cathode Materials during Delithiation

Kondrakov, Aleksandr Olegovič; Geßwein, Holger; Galdina, Kristina; De Biasi, Lea; Meded, Velimir; Filatova, Elena O.; Schumacher, Gerhard; Wenzel, Wolfgang; Hartmann,Pascal; Brezesinski, Torsten; Janek, Jürgen

Abstract (englisch):
Ni-rich LiNixCoyMnzO2 (NCM) cathode materials have great potential for application in next-generation lithium-ion batteries owing to their high specific capacity. However, they are subjected to severe structural changes upon (de)lithiation, which adversely affects the cycling stability. Herein, we investigate changes in crystal and electronic structure of NCM811 (80% Ni) at high states of charge by a combination of operando X-ray diffraction (XRD), operando hard X-ray absorption spectroscopy (hXAS), ex situ soft X-ray absorption spectroscopy (sXAS), and density functional theory (DFT) calculations, and correlate the results with data from galvanostatic cycling in coin cells. XRD reveals a large decrease in unit cell volume from 101.38(1) Å3 to 94.26(2) Å3 due to collapse of the interlayer spacing when x(Li) < 0.5 (decrease in c-axis from 14.469(1) Å at x(Li) = 0.6 to 13.732(2) Å at x(Li) = 0.25). hXAS shows that the shrinkage of the transition metal-oxygen layer mainly originates from nickel oxidation. sXAS, together with DFT-based Bader charge analysis, indicates that the shrinkage of the interlayer, which is occupied by lithium ... mehr

Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Institut für Angewandte Materialien - Werkstoffprozesstechnik (IAM-WPT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator ISSN: 1932-7447, 1932-7455
KITopen ID: 1000076121
HGF-Programm 37.01.01; LK 01
Erschienen in The journal of physical chemistry <Washington, DC> / C
Band 121
Heft 44
Seiten 24381-24388
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