Unveiling complex lithiation/delithiation mechanism in AgNbO3 model perovskite using operando X-ray absorption spectroscopy
Abstract
In AgNbO3 perovskite structure, electrochemical activation is speculated during the first lithiation cycle enabling the material to reversibly store Li+ by the contributions of both Ag and Nb cation. However, the origin of electrochemically induced structural activation and understanding of cations involvement in complex Li+ storage mechanism is still elusive. Herein, operando synchrotron X-ray absorption spectroscopy (XAS) was applied to clarify this mechanism under different cycling conditions. Ag K-edge XAS measurements during first lithiation revealed a gradual Ag+ to Ag0 reduction starting at a relatively high potential of 1.0 V vs Li+/Li, thus creating vacancies in the lattice for Li+ insertion and inducing a crystalline-to-amorphous structural transition. Below 0.3 V vs Li+/Li, metallic Ag forms multiple intermetallic Li-Ag alloys, resulting in lithium-rich Li9Ag at the end of lithiation. Simultaneously, Nb K-edge XAS measurements indicate an irreversible Nb5+ to Nb3+ reduction with formation of metastable phases during first lithiation. Upon extended cycling at high current densities, intermediate phases sustain reversible Li+ storage through Nb-redox activity and Li-Ag (de)alloying reactions, facilitating fast charging capability. This study will help in designing new conversion-alloying type negative electrodes for fast-charging batteries.
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BibTeX
@article{khan2026unveiling,
title = {{Unveiling complex lithiation/delithiation mechanism in AgNbO3 model perovskite using operando X-ray absorption spectroscopy}},
author = {Abbas Khan and Camille Douard and Antonella Iadecola and Thierry Brousse and Olivier Crosnier},
journal = {Electrochimica Acta},
year = {2026},
month = oct,
doi = {10.1016/j.electacta.2025.147435},
url = {https://hal.science/hal-05340406v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Unveiling complex lithiation/delithiation mechanism in AgNbO3 model perovskite using operando X-ray absorption spectroscopy
AU - Abbas Khan
AU - Camille Douard
AU - Antonella Iadecola
AU - Thierry Brousse
AU - Olivier Crosnier
PY - 2026
DA - 2026/10/07
JO - Electrochimica Acta
DO - 10.1016/j.electacta.2025.147435
UR - https://hal.science/hal-05340406v1
AB - In AgNbO3 perovskite structure, electrochemical activation is speculated during the first lithiation cycle enabling the material to reversibly store Li+ by the contributions of both Ag and Nb cation. However, the origin of electrochemically induced structural activation and understanding of cations involvement in complex Li+ storage mechanism is still elusive. Herein, operando synchrotron X-ray absorption spectroscopy (XAS) was applied to clarify this mechanism under different cycling conditions. Ag K-edge XAS measurements during first lithiation revealed a gradual Ag+ to Ag0 reduction starting at a relatively high potential of 1.0 V vs Li+/Li, thus creating vacancies in the lattice for Li+ insertion and inducing a crystalline-to-amorphous structural transition. Below 0.3 V vs Li+/Li, metallic Ag forms multiple intermetallic Li-Ag alloys, resulting in lithium-rich Li9Ag at the end of lithiation. Simultaneously, Nb K-edge XAS measurements indicate an irreversible Nb5+ to Nb3+ reduction with formation of metastable phases during first lithiation. Upon extended cycling at high current densities, intermediate phases sustain reversible Li+ storage through Nb-redox activity and Li-Ag (de)alloying reactions, facilitating fast charging capability. This study will help in designing new conversion-alloying type negative electrodes for fast-charging batteries.
SN - 0013-4686
ER -