The reactivity of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) solid electrolytes to form lithio-phobic species such as Li₂CO₃ on their surface when exposed to trace amounts of H₂O and CO₂ limits the progress of LLZTO-based solid-state batteries. Various treatments, such as annealing LLZTO within a glovebox or acid etching, aim at removing the surface contaminants, but a comprehensive understanding of the evolving LLZTO surface chemistry during and after these treatments is lacking. Here, glovebox-like H₂O and CO₂ conditions were recreated in a near ambient pressure X-ray photoelectron spectroscopy chamber to analyze the LLZTO surface under realistic conditions. We find that annealing LLZTO at 600 °C in this atmosphere effectively removes the surface contaminants, but a significant level of contamination reappears upon cooling down. In contrast, HCl_(aq) acid etching demonstrates superior Li₂CO₃ removal and stable surface chemistry post treatment. To avoid air exposure during the acid treatment, an anhydrous HCl solution in diethyl ether was used directly within the glovebox. This novel acid etching strategy delivers the lowest lithium/LLZTO interfacial resistance and the highest critical current density.

中文翻译：

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手套箱条件下 LLZTO 表面污染物的去除和重现


Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ (LLZTO)固体电解质形成的反应性当暴露于微量的 H ₂ O 和 CO ₂ 限制时，其表面会出现疏锂物质，例如 Li ₂ CO ₃ 基于LLZTO的固态电池的进展。各种处理（例如在手套箱内对 LLZTO 进行退火或酸蚀刻）旨在去除表面污染物，但缺乏对这些处理期间和之后不断变化的 LLZTO 表面化学的全面了解。在这里，在接近环境压力的 X 射线光电子能谱室中重现了类似手套箱的 H ₂ O 和 CO ₂ 条件，以在实际条件下分析 LLZTO 表面。我们发现，在这种气氛中 600 °C 下对 LLZTO 进行退火可以有效去除表面污染物，但冷却后会再次出现大量污染物。相比之下，HCl _(aq) 酸蚀刻表现出优异的 Li ₂ CO ₃ 去除效果和稳定的表面化学后处理。为了避免酸处理过程中暴露于空气，直接在手套箱内使用无水 HCl 乙醚溶液。这种新颖的酸蚀刻策略可提供最低的锂/LLZTO 界面电阻和最高的临界电流密度。