A Bipolar Separator for Autonomous Suppression of Dendrite Penetration in Zinc Metal Batteries
A Bipolar Separator for Autonomous Suppression of Dendrite Penetration in Zinc Metal Batteries
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用于自主抑制锌金属电池中枝晶穿透的双极分离器
DOI：
10.1149/1945-7111/acd8fc
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发表时间：
2023
影响因子：
3.9
通讯作者：
Bai, Peng
中科院分区：
文献类型：
--
作者：
Lee, Youngju;Bai, Peng
锌金属阳极为实现更经济、更可持续的储能装置而备受关注。然而，像其他金属阳极一样，多孔隔膜的树枝状生长和渗透仍然难以消除。在隔膜的孔壁上引入表面负电荷已被用来加强均匀的锌离子注入通量，以获得更均匀的电沉积，但由局部高电流密度引起的渗透仍然存在于现有的系统中。在这项工作中，我们首次报道了一种双极分离器，它利用了表面负电荷和正电荷的不同电渗效应。首次在透明的毛细管细胞中通过OPANDO视频显微镜验证了表面电荷对锌树枝晶生长的影响。通过将带正电的分离器堆叠在带负电的分离器上作为我们的概念验证，该系统先发制人地提供了通过负极层的均匀的锌离子通量，但饥饿阻止了已经自动渗透到负极层的局部金属生长。用对称电池进行的计时电势实验表明，与对照电池相比，短路时间延长了。带有双极分离器的全电池的恒流循环寿命实验表明，在10C的速率下，循环寿命达到5000次，没有金属渗透的迹象。
Zinc metal anodes are attracting much attention to enable more economical and sustainable energy storage devices. However, like other metal anodes, dendritic growths and penetrations of porous separators are still challenging to eliminate. Introducing negative surface charges on the pore walls of separators have been exploited to enforce a uniform incoming Zn-ion flux toward more uniform electrodeposition, but penetrations induced by localized high current densities still remain in available systems. In this work, we report, for the first time, a bipolar separator that exploits the distinct electroosmotic effects of the negative and the positive surface charges. The surface charge effects on Zn dendrite growths were first verified in transparent capillary cells via operando video microscopy. By stacking the positively charged separator over the negatively charged separator as our proof-of-concept, the system offers preemptively a uniform Zn-ion flux through the negative layer yet starve-stops local metal growths that already penetrated the negative layer autonomously. Chronopotentiometry experiments with the symmetric cells reveal extended short-circuit time compared to control cells. Galvanostatic cycle-life experiments of full cells with the bipolar separator showed excellent cycle life of 5,000 cycles at the rate of 10 C, without signs of metal penetration.