The thermal properties of yttrium-stabilized lithium zirconate phosphate [LZP: Li1+x+yYxZr2−x(PO4)3 with x = 0.15, −0.2 ≤ y ≤ 0.4 and with x = 0.0, y = 0.0] are presented over a wide temperature range from 30 to 973 K, elucidating the interplay between structural phase transformations and thermal properties in a solid state superionic conducting material. At room temperature, the thermal conductivity decreases by more than 75% as the stoichiometry is changed from lithium deficient to excess and increases with increasing temperature, indicative of defect-mediated transport in the spark plasma sintered materials. The phase transformations and their stabilities are examined by x-ray diffraction and differential scanning calorimetry and indicate that the Y3+ substitution of Zr4+ is effective in stabilizing the ionically conductive rhombohedral phase over the entire temperature range measured, the mechanism of which is found through ab initio theoretical calculations. These insights into thermal transport of LZP superionic conductors are valuable as they may be generally applicable for predicting material stability and thermal management in the ceramic electrolyte of future all-solid-state-battery devices.

中文翻译：

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相稳定的磷酸锆锂的热传输

钇稳定的磷酸锆锂 [LZP: Li1+x+yYxZr2−x(PO4)3 的热性能，x = 0.15, -0.2 ≤ y ≤ 0.4 和 x = 0.0, y = 0.0]温度范围从 30 到 973 K，阐明了固态超离子导电材料中结构相变和热性能之间的相互作用。在室温下，随着化学计量从锂不足变为过量，热导率下降超过 75%，并且随着温度的升高而增加，这表明放电等离子体烧结材料中的缺陷介导传输。通过 X 射线衍射和差示扫描量热法检查相变及其稳定性，表明 Y3+ 取代 Zr4+ 可有效地在整个测量温度范围内稳定离子导电菱形相，其机制通过从头算理论计算。这些对 LZP 超离子导体热传输的见解很有价值，因为它们通常可用于预测未来全固态电池设备陶瓷电解质中的材料稳定性和热管理。