Features of electronic states in the vicinity of band gap and atomic structure of Ta- and Nb-doped Li 7 La 3 Zr 2 O 12

Maxim I. Vlasov; Evgenii A. Surzhikov; Alexander Yu. Germov; Evgeniya A. Il'ina; Ilya A. Weinstein

doi:10.15826/chimtech.2024.11.2.07

Features of electronic states in the vicinity of band gap and atomic structure of Ta- and Nb-doped Li₇La₃Zr₂O₁₂

Maxim I. Vlasov, Evgenii A. Surzhikov, Alexander Yu. Germov, Evgeniya A. Il'ina, Ilya A. Weinstein

Abstract

Li₇La₃Zr₂O₁₂ is one the most promising materials for Li-conducting solid electrolytes. The incorporation of Ta⁵⁺ and Nb⁵⁺ into the Zr⁴⁺ sites stabilizes its cubic structure and significantly enhances Li-conductivity, due to the formation of Li vacancies. In this research, we have studied the band gap features of Ta and Nd-doped Li₇La₃Zr₂O₁₂. Our findings indicate that Nb ions are present not only in the +5 valence state, but also in the +4 state, leading to the formation of oxygen vacancies. In the case of the Ta-doping, such an effect was not observed. This could be the reason for the approximately one order of magnitude higher lithium conductivity observed in the case of the Ta doping, in comparison to the Nb doping.

Keywords

Li7La3Zr2O12; Ta and Nb doping; band gap; oxygen vacancies; Nb valence state

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DOI: https://doi.org/10.15826/chimtech.2024.11.2.07

Copyright (c) 2024 Maxim I. Vlasov, Evgenii A. Surzhikov, Alexander Yu. Germov, Evgeniya A. Il'ina, Ilya A. Weinstein

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