Structural and interfacial stability of a coated Ni-rich layered oxide cathode at high-voltage operation

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2025-06

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Mcode

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Language

en

Pages

12

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Materials Today Energy, Volume 50

Abstract

By increasing the cutoff potential of Ni-rich layered oxide cathodes, specifically LiNi0.8Co0.1Mn0.1O2 (NMC811), Li-ion batteries (LIBs) can deliver higher energy densities; a desirable performance trait in electric vehicle battery systems. However, this strategy compromises the structural and interfacial stability of NMC811, leading to a shorter operational lifetime. In this work, LixWyOz (LWO) coating is formed on the surface of a NMC811 active material to address the instability issues. LWO-NMC811 reports an improved cycling stability compared with an uncoated NMC811 at a high-voltage operation of 3.0–4.6 V. Operando X-ray diffraction and operando dilatometry are combined with ex-situ characterization techniques to elucidate the degradation mechanisms that occur in the cathode material from initial cycling to after 100 charge-discharge cycles. The multiscale analyses show that LWO-NMC811 experiences a suppressed H2→H3 contraction at the high state-of-charge, which results in lesser particle cracking and electrode thickness change. The LWO coating also diminishes the parasitic side reactions and supports the agile movement of Li+ at the electrode-electrolyte interface. Overall, this work demonstrates an inter-mapping of the complex deterioration processes that occur during high-voltage cycling of Ni-rich NMC, which is useful in optimizing electrode design to achieve high performance LIBs.

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Publisher Copyright: © 2025 The Authors

Keywords

Coating, High-voltage cycling, Interfacial stabilization, Ni-rich NMC, Operando dilatometry, Operando X-ray diffraction, W-modification

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Citation

Llanos, P S, Ahaliabadeh, Z, Miikkulainen, V, Kong, X, Obrezkov, F, Lahtinen, J, Yao, L, Jiang, H, Lassi, U & Kallio, T 2025, ' Structural and interfacial stability of a coated Ni-rich layered oxide cathode at high-voltage operation ', Materials Today Energy, vol. 50, 101862 . https://doi.org/10.1016/j.mtener.2025.101862