Lithium dendrite growth dynamics on Cu surface is first visualized through a versatile and facile experimental cell by in operando transmission X-ray microscopy (TXM). Galvanostatic plating and stripping cycle(s) are applied on each cell. Upon plating/stripping at ∼1 mA cm^–2, mossy lithium is clearly found growing and shrinking on the Cu surface as the application time increases. It is interesting to note that the aspect ratio (height/width) of deposited lithium has increased with charge passed during plating, indicating a faster growing from the base. In addition, the dendritic or mossy lithium has also been observed when various high current densities (25, 12.5, and 6.3 mA cm^–2) are applied in different cycles, showing a severe dendritic lithium formation that could be induced by inhomogeneous current distribution. The clear structure of dead lithium is found after the cycling, which also shows a lower efficiency and higher hazard when a higher current density is applied. This work explores TXM as a useful tool for in operando dynamic visualization and quantitative measurement of lithium dendrite, which is difficult to achieve with ex situ measurements and other microscopy techniques. The understanding of the growth mechanism from TXM can be beneficial for the development of safe lithium ion and lithium metal batteries.

中文翻译：

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通过Operando透射X射线显微镜对锂电镀和剥离的可视化

锂在Cu表面的枝晶生长动力学通过通用和容易的试验电池由第一可视化在operando透射X射线显微镜（TXM）。恒电流电镀和剥离周期适用于每个电池。在约1 mA cm ^{-2的条件下进行}电镀/剥离后，随着施加时间的增加，清楚地发现长满苔藓的锂在Cu表面生长和收缩。有趣的是，沉积的锂的长径比（高度/宽度）随着电镀过程中电荷的增加而增加，这表明从基体更快地生长。此外，当各种高电流密度（25、12.5和6.3 mA cm ^–2）以不同的周期施加，显示出严重的树枝状锂形成，这可能是由不均匀的电流分布引起的。循环后发现了死锂的清晰结构，当施加更高的电流密度时，它也显示出较低的效率和较高的危害。这项工作探索TXM作为一个有用的工具在operando动态可视化和锂枝晶定量测量，这是难以实现的易地测量和其他显微技术。了解TXM的生长机理可能对安全锂离子和锂金属电池的开发有益。