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Concentration polarization and metal dendrite initiation in isolated electrolyte microchannels
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2020-08-11 , DOI: 10.1039/d0ee01874k Youngju Lee 1, 2, 3, 4, 5 , Bingyuan Ma 1, 2, 3, 4, 5 , Peng Bai 1, 2, 3, 4, 5
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2020-08-11 , DOI: 10.1039/d0ee01874k Youngju Lee 1, 2, 3, 4, 5 , Bingyuan Ma 1, 2, 3, 4, 5 , Peng Bai 1, 2, 3, 4, 5
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Lithium metal penetrations through the liquid-electrolyte-wetted porous separator and solid electrolytes are a major safety concern of next-generation rechargeable metal batteries. Penetrations were frequently discovered to occur through only a few isolated channels, as revealed by “black spots” on both sides of the separator or electrolyte, which manifest a highly localized ionic flux or current density. Predictions of the penetration time have been difficult due to the hidden and unclear dynamics in these penetration channels. Here, using glass capillary cells, we investigate for the first time the unexpectedly sensitive influence of channel geometry on the concentration polarization and dendrite initiation processes. The characteristic time for the complete depletion of salt concentration at the surface of the advancing electrode, i.e. Sand's time, exhibits a nonlinear dependence on the curvature of the channel walls along the axial direction. While a positively deviated Sand's time scaling exponent can be used to infer a converging penetration area through the electrolyte, a negatively deviated scaling exponent suggests that diffusion limitations can be avoided in expanding channels, such that the fast-advancing tip-growing dendrites will not be initiated. The safety design of rechargeable metal batteries will benefit from considering the true local current densities and the conduction structures.
中文翻译：
隔离电解质微通道中的浓度极化和金属枝晶萌生
锂离子穿过液体电解质润湿的多孔隔板和固体电解质的渗透是下一代可充电金属电池的主要安全问题。经常发现渗透仅通过少数几个隔离的通道发生，如隔板或电解质两侧的“黑点”所示，这表明离子流或电流密度高度局部化。由于这些渗透通道中隐藏的和不清楚的动态，因此难以预测渗透时间。在这里，我们使用玻璃毛细管，首次研究了通道几何形状对浓度极化和枝晶引发过程的意想不到的敏感影响。完全耗尽前进电极表面上的盐浓度的特征时间，也就是说，沙的时间对通道壁沿轴向的曲率呈非线性关系。尽管可以使用正偏差Sand的时间缩放指数来推断通过电解液的会聚渗透区域，但是负偏差缩放指数则表明可以避免扩展通道中的扩散限制，因此不会快速增长的尖端生长树枝状晶体。启动。考虑到真实的局部电流密度和传导结构，可充电金属电池的安全设计将受益。
更新日期：2020-10-14
中文翻译：
隔离电解质微通道中的浓度极化和金属枝晶萌生
锂离子穿过液体电解质润湿的多孔隔板和固体电解质的渗透是下一代可充电金属电池的主要安全问题。经常发现渗透仅通过少数几个隔离的通道发生，如隔板或电解质两侧的“黑点”所示，这表明离子流或电流密度高度局部化。由于这些渗透通道中隐藏的和不清楚的动态，因此难以预测渗透时间。在这里，我们使用玻璃毛细管，首次研究了通道几何形状对浓度极化和枝晶引发过程的意想不到的敏感影响。完全耗尽前进电极表面上的盐浓度的特征时间，也就是说，沙的时间对通道壁沿轴向的曲率呈非线性关系。尽管可以使用正偏差Sand的时间缩放指数来推断通过电解液的会聚渗透区域，但是负偏差缩放指数则表明可以避免扩展通道中的扩散限制，因此不会快速增长的尖端生长树枝状晶体。启动。考虑到真实的局部电流密度和传导结构，可充电金属电池的安全设计将受益。
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