Zhang Yuchen, Qiu Zhengfu, Wang Zhuyi, Yuan Shuai
Research Centre of Nanoscience and Nanotechnology, Shanghai University, Shanghai 200444, China.
Research Centre of Nanoscience and Nanotechnology, Shanghai University, Shanghai 200444, China.
J Colloid Interface Sci. 2022 Feb;607(Pt 1):742-751. doi: 10.1016/j.jcis.2021.09.030. Epub 2021 Sep 14.
An organic/inorganic hybrid coating consisting of molecular sieve (MS)/sulfonated melamine formaldehyde condensate (SMF) is fabricated on the polyethylene (PE) separator by a simple dip-coating process. The MS/SMF coating with high polarity enhances the electrolyte uptake of PE separator, and therefore favors higher ionic conductivity and Li transference number of separators. By regulating the ratio of MS/SMF, much higher Li transference number up to 0.5 can be obtained compared with the original PE separator (0.25). The PE separator possesses highest effective Li ionic conductivity when the ratio of MS/SMF is 3:1, which promotes more uniform Li deposition on the lithium metal surface for excellent lithium plating/stripping cycling stability up to 1000 h without any signs of short-circuit. Moreover, the functional PE separator possesses excellent HO and HF capturing ability due to strong adsorption of MS and SMF for HO and the scavenging of SMF for HF. The MS-SMF@PE separator-employed LiCoO/Li unit cell shows superior C-rates capability and cycling performance, and no obvious lithium dendrite growth is found on the surface of lithium metal anode after cycling.
通过简单的浸涂工艺在聚乙烯（PE）隔膜上制备了一种由分子筛（MS）/磺化三聚氰胺甲醛缩合物（SMF）组成的有机/无机杂化涂层。具有高极性的MS/SMF涂层提高了PE隔膜对电解质的吸收，因此有利于提高隔膜的离子电导率和锂迁移数。通过调节MS/SMF的比例，与原始PE隔膜（0.25）相比，可以获得高达0.5的更高锂迁移数。当MS/SMF比例为3:1时，PE隔膜具有最高的有效锂离子电导率，这促进了锂金属表面更均匀的锂沉积，实现了高达1000小时的优异锂电镀/剥离循环稳定性，且无任何短路迹象。此外，由于MS和SMF对HO的强吸附以及SMF对HF的清除作用，功能性PE隔膜具有优异的HO和HF捕获能力。采用MS-SMF@PE隔膜的LiCoO/Li单电池显示出优异的倍率性能和循环性能，循环后锂金属阳极表面未发现明显的锂枝晶生长。
