Current direct observation of sensitive battery materials and interfaces primarily relies on two-dimensional (2D) imaging, leaving out their three-dimensional (3D) relationship. Here, we used cryogenic electron tomography (cryo-ET) to visualize the lithium metal anode in 3D at nanometer resolution and cryogenic electron microscopy (cryo-EM) to reveal atomic details in local regions. We imaged both freshly prepared and calendar aged Li metal anodes to reveal the development of LiH in Li dendrites and the Li-LiH interface, as well as the development of the solid-electrolyte interphase (SEI). Using a convolutional neural network-based technique, the 3D arrangement of Li metal, along with nanoscale LiH and Cu heterogeneities in dendrites were visualized and annotated. In longer-term calendar aging, we observed more substantial LiH growth accompanied by extended SEI growth. Our results show that the growth of LiH and of the extended SEI during battery calendar aging are temporally and spatially separate processes

中文翻译：

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使用低温电子断层扫描解析锂金属电池中的三维纳米级异质性


目前对敏感电池材料和界面的直接观察主要依赖于二维 （2D） 成像，而忽略了它们的三维 （3D） 关系。在这里，我们使用低温电子断层扫描 （cryo-ET） 以纳米分辨率以 3D 形式可视化锂金属阳极，并使用低温电子显微镜 （cryo-EM） 来揭示局部区域的原子细节。我们对新鲜制备的和历时老化的锂金属负极进行了成像，以揭示锂枝晶和 Li-LiH 界面中 LiH 的发育，以及固体电解质界面 （SEI） 的发展。使用基于卷积神经网络的技术，对锂金属的 3D 排列以及树突中的纳米级 LiH 和 Cu 异质性进行了可视化和注释。在长期日历老化中，我们观察到 LiH 增长更显著，并伴有 SEI 增长延长。我们的结果表明，在电池日历老化过程中，LiH 和扩展 SEI 的增长是时间和空间上独立的过程