Journal article

Publication year: 2017

Pages: 24381-24388

Journal: Journal of Physical Chemistry C

Volume number: 121

Issue number: 44

ISSN: 1932-7447

Open access status: Green

DOI Link: https://doi.org/10.1021/acs.jpcc.7b06598

Publisher: American Chemical Society

Abstract: 
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) to 94.26(2) angstrom(3) due to collapse of the interlayer spacing when x(Li) < 0.5 (decrease in c-axis from 14.469(1) angstrom at x(Li) = 0.6 to 13.732(2) angstrom 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, is induced by charge transfer between O 2p and partially filled Ni e(g) orbitals (resulting in decrease of oxygen-oxygen repulsion). Overall, the results demonstrate that high voltage operation of NCM811 cathodes is inevitably accompanied by charge-transfer-induced lattice collapse.

Harvard Citation style: Kondrakov, A., Gesswein, H., Galdina, K., de Biasi, L., Meded, V., Filatova, E., et al. (2017) Charge-Transfer-Induced Lattice Collapse in Ni-Rich NCM Cathode Materials during Delithiation, Journal of Physical Chemistry C, 121(44), pp. 24381-24388. https://doi.org/10.1021/acs.jpcc.7b06598

APA Citation style: Kondrakov, A., Gesswein, H., Galdina, K., de Biasi, L., Meded, V., Filatova, E., Schumacher, G., Wenzel, W., Hartmann, P., Brezesinski, T., & Janek, J. (2017). Charge-Transfer-Induced Lattice Collapse in Ni-Rich NCM Cathode Materials during Delithiation. Journal of Physical Chemistry C. 121(44), 24381-24388. https://doi.org/10.1021/acs.jpcc.7b06598