Gullbrekken Øystein, Eggestad Kristoffer, Tsoutsouva Maria, Williamson Benjamin A D, Rettenwander Daniel, Einarsrud Mari-Ann, Selbach Sverre M
Department of Materials Science and Engineering, Norwegian University of Science and Technology, NTNU, Trondheim N-7491, Norway.
Inorg Chem. 2025 Mar 31;64(12):5856-5865. doi: 10.1021/acs.inorgchem.4c03738. Epub 2025 Mar 18.
The cubic garnet LiLaZrO (LLZO) is a prototypical ceramic electrolyte for solid-state Li-ion batteries. While the electrochemical performance of LLZO is well studied, the thermodynamics of the formation of LLZO is not fully understood, and reliable synthesis of phase-pure cubic LLZO requires such knowledge. Here, we report a high-temperature X-ray diffraction (HTXRD) study of the crystallization of Al-doped LLZO from an amorphous gel with different amounts of excess Li. Based on the phases identified in the precursor powders before and during heating, a net chemical reaction for the formation of LLZO is proposed, and its thermodynamic properties are calculated. The sample thickness, and hence the surface exposure to the atmosphere during calcination, strongly affects the phase evolution of cubic LLZO. The configurational entropy of cubic LLZO is estimated to be large and necessary to stabilize cubic LLZO.
立方石榴石LiLaZrO（LLZO）是一种用于固态锂离子电池的典型陶瓷电解质。虽然对LLZO的电化学性能已进行了充分研究，但LLZO形成的热力学尚未完全理解，而可靠合成纯相立方LLZO需要此类知识。在此，我们报告了一项高温X射线衍射（HTXRD）研究，该研究针对不同过量锂含量下从非晶态凝胶中结晶出的铝掺杂LLZO展开。基于加热前后前驱体粉末中鉴定出的相，提出了形成LLZO的净化学反应，并计算了其热力学性质。样品厚度以及因此在煅烧过程中表面暴露于大气的情况，对立方LLZO的相演变有强烈影响。据估计，立方LLZO的构型熵很大，这对于稳定立方LLZO是必要的。
