Structure and evolution of disordered deep-charge phases in Na_xCrO₂ Na-ion battery electrodes

TY - JOUR

T1 - Structure and evolution of disordered deep-charge phases in NaxCrO2 Na-ion battery electrodes

AU - Jakobsen, Christian Lund

AU - Andersen, Bettina Pilgaard

AU - Johansen, Morten

AU - Christensen, Christian Kolle

AU - Drejer, Andreas Østergaard

AU - Karlsen, Martin Aaskov

AU - Ravnsbæk, Dorthe Bomholdt

N1 - Publisher Copyright: © 2023 The Authors

PY - 2024/1/30

Y1 - 2024/1/30

N2 - Layered sodium chromium oxide, O3–NaCrO2, is a promising electrode material for Na-ion batteries due to the high thermal stability, high rate-capability, and good coulombic efficiency of the material. However, it is well-known that the material loses crystallinity and the ability to store Na-ions reversibly when taken to high states of charge. While the structural identity of the disordered state has been investigated, a bulk structural model has so far been lacking, as has the mechanism for the order-disorder transition from the P′3-NaxCrO2 (the last crystalline phase observed during charge) to the disordered state. In this work, we combine pair distribution function analysis from total X-ray scattering and powder X-ray diffraction to obtain a complete structural model for the disordered O3-like NaxCrO2 forming at high states-of-charge, and from operando pair distribution function analysis and X-ray absorption spectroscopy, we elucidate the structural evolution of the order-disorder transition and shed new light on the Cr-migration in the disordered state, which is the cause of the irreversibility of the Na-ion storage.

AB - Layered sodium chromium oxide, O3–NaCrO2, is a promising electrode material for Na-ion batteries due to the high thermal stability, high rate-capability, and good coulombic efficiency of the material. However, it is well-known that the material loses crystallinity and the ability to store Na-ions reversibly when taken to high states of charge. While the structural identity of the disordered state has been investigated, a bulk structural model has so far been lacking, as has the mechanism for the order-disorder transition from the P′3-NaxCrO2 (the last crystalline phase observed during charge) to the disordered state. In this work, we combine pair distribution function analysis from total X-ray scattering and powder X-ray diffraction to obtain a complete structural model for the disordered O3-like NaxCrO2 forming at high states-of-charge, and from operando pair distribution function analysis and X-ray absorption spectroscopy, we elucidate the structural evolution of the order-disorder transition and shed new light on the Cr-migration in the disordered state, which is the cause of the irreversibility of the Na-ion storage.

KW - Cathodes

KW - Layered transition metal oxide

KW - Na-ion batteries

KW - NaCrO

KW - Operando

KW - Pair distribution function analysis

KW - Powder X-ray diffraction

UR - http://www.scopus.com/inward/record.url?scp=85178605636&partnerID=8YFLogxK

U2 - 10.1016/j.jpowsour.2023.233875

DO - 10.1016/j.jpowsour.2023.233875

M3 - Journal article

AN - SCOPUS:85178605636

SN - 0378-7753

VL - 591

JO - Journal of Power Sources

JF - Journal of Power Sources

M1 - 233875

ER -