A Scalable Approach for Dendrite-Free Alkali Metal Anodes via Room-Temperature Facile Surface Fluorination
A Scalable Approach for Dendrite-Free Alkali Metal Anodes via Room-Temperature Facile Surface Fluorination
复制标题
通过室温轻松表面氟化制备无枝晶碱金属阳极的可扩展方法
DOI：
10.1021/acsami.8b18101
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发表时间：
2019-02-06
影响因子：
9.5
通讯作者：
Liu, Meilin
中科院分区：
文献类型：
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作者：
Wang, Gang;Xiong, Xunhui;Liu, Meilin
碱金属具有较高的理论比容量和较低的电化学电位，是先进高能量密度电池系统中极具吸引力的负极材料。然而，严重的枝晶生长和高化学反应性限制了它们在储能技术中的实际应用。在此，我们提出了一种易于扩展的基于溶液的方法，通过在电池组装前将Li/Na金属浸入无害的离子液体1-丁基-2,3-二甲基咪唑四氟硼酸盐中几分钟的简单过程来稳定Li和Na阳极。通过离子液体和Li/Na金属的原位反应，产生了致密而坚固的人工氟化物层。结果表明，该方法在锂金属阳极表面制备了均匀致密的LiF涂层，有效抑制了锂枝晶的生长和循环过程中电解质的持续分解。结果，在1ma cm（-2）下，lif涂层的金属锂阳极在低过电位（类似于22 mV）下实现了超过700小时的增强循环寿命，以及在1ma cm（-2）下200次循环高达98.1%的非常高的库仑效率。此外，无枝晶Na沉积的成功成果显示了室温表面氟化的多功能性，具有潜在的电池应用前景。
Alkali metals are attractive anode materials for advanced high-energy density battery systems because of their high theoretical specific capacities as well as low electrochemical potential. However, severe dendrite growth as well as high chemical reactivity restrict their practical application in energy storage technologies. Herein, we propose a facile scalable solution-based approach to stabilize Li and Na anodes via the facile process of immersing the Li/Na metal in a nonhazardous ionic liquid 1-butyl-2,3-dimethylimidazolium tetrafluoroborate for several minutes at room temperature before battery assembly. This produces a dense and robust artificial fluoride layer, formed in situ by the reaction of the ionic liquid and Li/Na metal. As a demonstration, a homogeneous and compact LiF coating on the Li metal anode was fabricated via our method and it can effectively suppress the growth of Li dendrites and the continuous decomposition of electrolytes during cycling. As a result, the LiF-coated metallic Li anode achieves an enhanced cycling lifespan of over 700 h with low overpotential (similar to 22 mV) at 1 mA cm(-2), as well as a very high Coulombic efficiency of up to 98.1% for 200 cycles at 1 mA cm(-2). Furthermore, the successful achievements of the dendrite-free Na deposition show the versatility of room-temperature surface fluorination for potential battery applications.