Squires, AG;
Scanlon, DO;
Morgan, BJ;
(2020)
Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li₇La₃Zr₂O₁₂.
Chemistry of Materials
, 32
(5)
pp. 1876-1886.
10.1021/acs.chemmater.9b04319.
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Abstract
The Li-stuffed garnets LixM2M3′O12 are promising Li-ion solid electrolytes with potential use in solid-state batteries. One strategy for optimizing ionic conductivities in these materials is to tune lithium stoichiometries through aliovalent doping, which is often assumed to produce proportionate numbers of charge-compensating Li vacancies. The native defect chemistry of the Li-stuffed garnets and their response to doping, however, are not well understood, and it is unknown to what degree a simple vacancy-compensation model is valid. Here, we report hybrid density functional theory calculations of a broad range of native defects in the prototypical Li garnet Li7La3Zr2O12. We calculate equilibrium defect concentrations as a function of synthesis conditions and model the response of these defect populations to extrinsic doping. We predict a rich defect chemistry that includes Li and O vacancies and interstitials, and significant numbers of cation-antisite defects. Under reducing conditions, O vacancies act as color centers by trapping electrons. We find that supervalent (donor) doping does not produce charge compensating Li vacancies under all synthesis conditions; under Li-rich/Zr-poor conditions the dominant compensating defects are LiZr antisites, and Li stoichiometries strongly deviate from those predicted by simple “vacancy compensation” models.
Type: | Article |
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Title: | Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li₇La₃Zr₂O₁₂ |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1021/acs.chemmater.9b04319 |
Publisher version: | http://dx.doi.org/10.1021/acs.chemmater.9b04319 |
Language: | English |
Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
Keywords: | Defects in solids, Energy, Defects, Lithium, Doping |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
URI: | https://discovery.ucl.ac.uk/id/eprint/10092931 |
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