Over the last decade, Li₇La₃Zr₂O₁₂ (LLZO) has shown to be one of the most promising materials as a solid electrolyte in Li-ion batteries. However, several factors can affect the final electrochemical properties of the material, such as the synthesis method and the inclusion of dopants. In this study, we conduct a comparative analysis of undoped and Al-doped LLZO prepared through solid state and sol-gel methods. An in-situ thermal investigation on the synthesis of LLZO shows how solid state synthesis forms LLZO at lower rates, however the resulting LLZO is more stable at higher temperatures. The addition of Al as a dopant further increases the thermal stability of the material by lowering its decomposition rate. Ionic conductivity measurements reveal how sol-gel LLZO samples experience several times higher conductivity than their solid state counterparts due to tightly interconnected grains. With the addition of Al, the conductivity further increases by two orders of magnitude. With that we are able to achieve the highest ionic conductivity of 4.96 × 10⁻⁴ S/cm for Al-doped sol-gel LLZO and an activation energy of 0.28(1) eV. This work provides a better understanding of how different synthesis methods affect the final properties of LLZO solid electrolytes.

在过去的十年中，Li ₇ La ₃ Zr ₂ O ₁₂ (LLZO) 已被证明是锂离子电池中最有前途的固体电解质材料之一。然而，有几个因素会影响材料的最终电化学性能，例如合成方法和掺杂剂的加入。在这项研究中，我们对通过固态和溶胶-凝胶法制备的未掺杂和铝掺杂的 LLZO 进行了比较分析。一个原地对 LLZO 合成的热研究表明，固态合成如何以较低的速率形成 LLZO，但所得的 LLZO 在较高温度下更稳定。添加Al作为掺杂剂通过降低其分解速率进一步提高了材料的热稳定性。离子电导率测量揭示了溶胶-凝胶 LLZO 样品的电导率是如何由于紧密互连的晶粒而比固态样品高出数倍的。随着Al的添加，电导率进一步增加了两个数量级。这样，我们能够实现 4.96 × 10 ^{-4的最高离子电导率} 掺杂铝的溶胶-凝胶 LLZO 的 S/cm 和 0.28(1) eV 的活化能。这项工作提供了对不同合成方法如何影响 LLZO 固体电解质最终性能的更好理解。