Atomistic Interpretation of the Oxygen K-Edge X-ray Absorption Spectra of Layered Li-Ion Battery Cathode Materials

TY - JOUR

T1 - Atomistic Interpretation of the Oxygen K-Edge X-ray Absorption Spectra of Layered Li-Ion Battery Cathode Materials

AU - Ramesh, Namrata

AU - Banerjee, Hrishit

AU - Swallow, Jack E. N.

AU - Björklund, Erik

AU - Dean, Ava

AU - Didwal, Pravin

AU - Fraser, Michael

AU - Phelan, Conor M. E.

AU - An, Lijin

AU - Singh, Jasper

AU - Lewis, Jarrod

AU - Song, Weixin

AU - House, Robert A.

AU - Morris, Andrew J.

AU - Weatherup, Robert S.

AU - Nicholls, Rebecca J.

N1 - Publisher Copyright: © 2024 The Authors. Published by American Chemical Society.

PY - 2024/11/12

Y1 - 2024/11/12

N2 - Core loss spectroscopies can provide powerful element-specific insight into the redox processes occurring in Li-ion battery cathodes, but this requires an accurate interpretation of the spectral features. Here, we systematically interpret oxygen K-edge core loss spectra of layered lithium transition-metal (TM) oxides (LiMO 2, where M = Co, Ni, Mn) from first principles using density-functional theory (DFT). Spectra are simulated using three exchange-correlation functionals, comprising the generalized gradient approximation (GGA) functional PBE, the DFT-PBE + Hubbard U method, and the meta-GGA functional rSCAN. In general, rSCAN provides a better match to experimentally observed excitation energies of spectral features compared to both PBE and PBE + U, especially at energies close to the main edge. Projected density of states of core-hole calculations show that the O orbitals are better described by rSCAN. Hybridization, structural distortions, chemical composition, and magnetism significantly influence the spectra. The O K-edge spectrum of LiNiO 2 obtained using rSCAN shows a closer match to the experimental X-ray absorption spectroscopy (XAS) when derived from a simulation cell which includes a Jahn-Teller distortion, showing that the DFT-calculated pre-edge feature contains information about not only chemical species but also geometric distortion. Core loss spectra derived from DFT can also differentiate between materials with the same structure and magnetic configuration but comprising different TMs; these differences are comparable to those observed in experimental XAS from the same materials. This foundational work helps establish the extent to which DFT can be used to bridge the interpretation gap between experimental spectroscopic signatures and ab initio methods describing complex battery materials, such as lithium nickel manganese cobalt oxides.

AB - Core loss spectroscopies can provide powerful element-specific insight into the redox processes occurring in Li-ion battery cathodes, but this requires an accurate interpretation of the spectral features. Here, we systematically interpret oxygen K-edge core loss spectra of layered lithium transition-metal (TM) oxides (LiMO 2, where M = Co, Ni, Mn) from first principles using density-functional theory (DFT). Spectra are simulated using three exchange-correlation functionals, comprising the generalized gradient approximation (GGA) functional PBE, the DFT-PBE + Hubbard U method, and the meta-GGA functional rSCAN. In general, rSCAN provides a better match to experimentally observed excitation energies of spectral features compared to both PBE and PBE + U, especially at energies close to the main edge. Projected density of states of core-hole calculations show that the O orbitals are better described by rSCAN. Hybridization, structural distortions, chemical composition, and magnetism significantly influence the spectra. The O K-edge spectrum of LiNiO 2 obtained using rSCAN shows a closer match to the experimental X-ray absorption spectroscopy (XAS) when derived from a simulation cell which includes a Jahn-Teller distortion, showing that the DFT-calculated pre-edge feature contains information about not only chemical species but also geometric distortion. Core loss spectra derived from DFT can also differentiate between materials with the same structure and magnetic configuration but comprising different TMs; these differences are comparable to those observed in experimental XAS from the same materials. This foundational work helps establish the extent to which DFT can be used to bridge the interpretation gap between experimental spectroscopic signatures and ab initio methods describing complex battery materials, such as lithium nickel manganese cobalt oxides.

KW - Chemical structure

KW - Transition metals

KW - Energy

KW - Materials

KW - Oxides

UR - https://ora.ox.ac.uk/objects/uuid:2c3e5e7d-c1b1-4f2a-b012-2e48c95e551f

UR - https://www.scopus.com/pages/publications/85209108203

U2 - 10.1021/acs.chemmater.4c01870

DO - 10.1021/acs.chemmater.4c01870

M3 - Article

C2 - 39618489

SN - 0897-4756

VL - 36

SP - 11051

EP - 11064

JO - Chemistry of Materials

JF - Chemistry of Materials

IS - 22

ER -