Issue 29, 2024

Thermal properties and lattice anharmonicity of Li-ion conducting garnet solid electrolyte Li6.5La3Zr1.5Ta0.5O12

Abstract

Garnet-type solid electrolytes have garnered significant interest for all-solid-state battery applications due to their high Li-ion conductivity and excellent compatibility with the metallic lithium anode. Although their ionic conductivity optimization and conduction mechanisms have been extensively studied, the thermal properties of garnet electrolytes remain poorly understood. The thermal conductivity, thermal expansion coefficient, and specific heat of solid electrolytes play a crucial role in determining the overall performance, safety, and reliability of battery devices. Understanding these properties is essential for enhanced thermal management and improved energy efficiency of batteries. Here, we investigate the thermal properties of Ta5+-doped garnet Li6.5La3Zr1.5Ta0.5O12 (LLZTO) polycrystals. The thermal conductivity measurement reveals a low-temperature peak at around 50 K. Above this temperature, the thermal conductivity shows a weak temperature dependence and approaches the calculated minimum thermal conductivity. The average phonon mean free path increases as the temperature decreases, reaching approximately 500 nm at 5 K. The linear thermal expansion coefficient obtained through the X-ray diffraction measurements is 1.71 ± 0.01 × 10−5 K−1 at 323 K, larger than the reported value for undoped Li7La3Zr2O12. The Grüneisen parameter of LLZTO calculated using the measured thermal expansion coefficient and specific heat is 1.63 ± 0.04 at 300 K, indicating relatively strong phonon anharmonicity. Furthermore, the thermal conductivity of aged LLZTO is increased by 70–80% at 300 K compared to the pristine samples, which can be attributed to the formation of Li2CO3 with increased thermal conductivity or reduced thermal boundary resistance. Our results provide useful insights into the structure–thermal property relationships that are closely relevant to thermal management of battery systems based on garnet solid electrolytes.

Graphical abstract: Thermal properties and lattice anharmonicity of Li-ion conducting garnet solid electrolyte Li6.5La3Zr1.5Ta0.5O12

Supplementary files

Article information

Article type
Paper
Submitted
03 Apr 2024
Accepted
17 Jun 2024
First published
17 Jun 2024

J. Mater. Chem. A, 2024,12, 18248-18257

Thermal properties and lattice anharmonicity of Li-ion conducting garnet solid electrolyte Li6.5La3Zr1.5Ta0.5O12

Y. Wang, S. Li, N. Wu, Q. Jia, T. Hoke, L. Shi, Y. Li and X. Chen, J. Mater. Chem. A, 2024, 12, 18248 DOI: 10.1039/D4TA02264E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements