Yang Mao, Jue Nan, Chen Yuanfu, Wang Yong
State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Nanoscale Res Lett. 2021 Mar 23;16(1):52. doi: 10.1186/s11671-021-03508-z.
Uniform migration of lithium (Li) ions between the separator and the lithium anode is critical for achieving good quality Li deposition, which is of much significance for lithium metal battery operation, especially for Li-sulfur (Li-S) batteries. Commercial separators such as polypropylene or polyethylene can be prepared by wet or dry processes, but they can indeed cause plentiful porosities, resulting in the uneven Li ion stripping/plating and finally the formation of Li dendrites. Thence, we constructed an atomic interlamellar ion channel by introducing the layered montmorillonite on the surface of the separator to guide Li ion flux and achieved stable Li deposition. The atomic interlamellar ion channel with a spacing of 1.4 nm showed strong absorption capacity for electrolytes and reserved capacity for Li ions, thus promoting rapid transfer of Li ions and resulting in even Li ion deposition at the anode. When assembled with the proposed separator, the Coulombic efficiency of Li||Cu batteries was 98.2% after 200 cycles and stable plating/stripping even after 800 h was achieved for the Li||Li symmetric batteries. Importantly, the proposed separator allows 140% specific capacity increase after 190 cycles as employing the Li-S batteries.
锂离子在隔膜与锂负极之间的均匀迁移对于实现高质量的锂沉积至关重要，这对锂金属电池的运行具有重要意义，特别是对于锂硫（Li-S）电池。诸如聚丙烯或聚乙烯之类的商用隔膜可通过湿法或干法制备，但它们确实会产生大量孔隙，导致锂离子的不均匀脱嵌/沉积，最终形成锂枝晶。因此，我们通过在隔膜表面引入层状蒙脱石构建了一个原子层间离子通道，以引导锂离子通量并实现稳定的锂沉积。间距为1.4纳米的原子层间离子通道对电解质表现出强大的吸收能力，并保留锂离子的容量，从而促进锂离子的快速转移，并导致锂离子在负极均匀沉积。当与所提出的隔膜组装时，Li||Cu电池在200次循环后的库仑效率为98.2%，Li||Li对称电池即使在800小时后也实现了稳定的镀锂/脱锂。重要的是，在所使用的Li-S电池中，所提出的隔膜在190次循环后可使比容量提高140%。
