‘Oxygen Bound to Magnesium’ as High Voltage Redox Center Causes Sloping of the Potential Profile in Mg‐Doped Layered Oxides for Na‐Ion Batteries

Abstract >The potential profile of layered oxides as cathodes for Na‐ion batteries can be well tuned by cation doping. Doping typically leads to changes in the phase behavior and the redox chemistry, but the underlying mechanisms remain poorly understood, especially at potentials above ≈4 V vs. Na + /Na. Here, the influence of Mg‐doping on the properties of layered O3‐NaNi 0.5 Mn 0.5 O 2 is studied by means of synchrotron methods (XAS, RIXS, operando XRD) and DFT calculations. A strong oxygen redox activity is observed at high voltages, and Mg is found to induce an OP2 phase at low concentration (10%) and a solid solution type reaction at a high concentration (25%), thus greatly enhancing the cycle life. The change toward a more sloping charge profile with increasing Mg content is caused by a new redox center (arising from the ‘O bound to Mg') having a higher redox potential but being more irreversible compared to the redox activity of ‘O bound to Ni'. The appearance of an additional redox center explains findings obtained for other doped Ni‐ and Mn‐based layered oxides, which also show a sloping potential in the high voltage region.

Authors

Institutions

Publication Details

Journal
Advanced Functional Materials
Published
2025-11-10
DOI
https://doi.org/10.1002/adfm.202519132
Primary Topic
Advancements in Battery Materials
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

‘Oxygen Bound to Magnesium’ as High Voltage Redox Center Causes Sloping of the Potential Profile in Mg‐Doped Layered Oxides for Na‐Ion Batteries

Payam Kaghazchi, Christian Schulz, Götz Schuck, M. Zając et al.
Advanced Functional Materials
Advancements in Battery Materials
article

‘Oxygen Bound to Magnesium’ as High Voltage Redox Center Causes Sloping of the Potential Profile in Mg‐Doped Layered Oxides for Na‐Ion Batteries

Payam Kaghazchi, Christian Schulz, Götz Schuck, M. Zając, Alba San José Méndez, Konstantin Köster, Philipp Adelhelm, Yanan Sun, Katherine A. Mazzio, Yongchun Li, Volodymyr Baran, Deniz Wong, Annica I. Freytag
article en

Abstract

Abstract >The potential profile of layered oxides as cathodes for Na‐ion batteries can be well tuned by cation doping. Doping typically leads to changes in the phase behavior and the redox chemistry, but the underlying mechanisms remain poorly understood, especially at potentials above ≈4 V vs. Na + /Na. Here, the influence of Mg‐doping on the properties of layered O3‐NaNi 0.5 Mn 0.5 O 2 is studied by means of synchrotron methods (XAS, RIXS, operando XRD) and DFT calculations. A strong oxygen redox activity is observed at high voltages, and Mg is found to induce an OP2 phase at low concentration (10%) and a solid solution type reaction at a high concentration (25%), thus greatly enhancing the cycle life. The change toward a more sloping charge profile with increasing Mg content is caused by a new redox center (arising from the ‘O bound to Mg') having a higher redox potential but being more irreversible compared to the redox activity of ‘O bound to Ni'. The appearance of an additional redox center explains findings obtained for other doped Ni‐ and Mn‐based layered oxides, which also show a sloping potential in the high voltage region.

Advanced Functional MaterialsVol. 36(23)
TU Wien (AT), Forschungszentrum Jülich (DE), Helmholtz-Zentrum Berlin für Materialien und Energie (DE), Deutsches Elektronen-Synchrotron DESY (DE), Humboldt-Universität zu Berlin (DE), National Synchrotron Radiation Laboratory (CN), University of Twente (NL)
Bundesministerium für Bildung und Forschung, China Scholarship Council
Openalex Percentile: Top 67%
Advancements in Battery Materials
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.