Doping implications of Li solid state electrolyte Li7La3Zr2O12

Solid-state electrolytes, like Li7La3Zr2O12 (LLZO), can enable safer, more energy dense and longer lasting batteries. We investigate the effect of doping in LLZO with Al, Ga, Nb, Ta, and Y by hybrid density functional theory calculations and a full defect model. The site preferences of Al, Ga, Nb, a...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-07, Vol.12 (26), p.15666-15675
Main Authors: Eggestad, Kristoffer, Selbach, Sverre M, Williamson, Benjamin A D
Format: Article
Language:English
Subjects:
Current carriers
Defects
Density functional theory
Doping
Electrolytes
Free energy
Gallium
Heat of formation
Ion currents
Molten salt electrolytes
Niobium
Solid electrolytes
Solid state
Tantalum
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Summary:Solid-state electrolytes, like Li7La3Zr2O12 (LLZO), can enable safer, more energy dense and longer lasting batteries. We investigate the effect of doping in LLZO with Al, Ga, Nb, Ta, and Y by hybrid density functional theory calculations and a full defect model. The site preferences of Al, Ga, Nb, and Ta result in donor defects that favour more Li vacancies and thus a more disordered Li substructure. This also implies stabilisation of the more ionic conducting cubic phase at the expense of the tetragonal, as seen experimentally. Furthermore, our calculations indicate that the effect of the dopants on the sintering process is even more important than the ability to induce more ionic charge carriers. Finally, differences in Li vacancy formation energies suggest a new possible explanation for the two orders of magnitude increase in ionic conductivity upon stabilising the cubic phase.
ISSN:2050-7488
2050-7496
DOI:10.1039/d4ta01487a