Feng Yunchong, Zhu Xuebing, Bian Tengfei, Liu Zewen, Zhao Long, Wang Jinhao, He Jinling, Zhao Yong
Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, School of Materials Science and Engineering, Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng, 475004, P. R. China.
Small. 2024 Oct;20(40):e2401940. doi: 10.1002/smll.202401940. Epub 2024 Jun 7.
Porous polymer membranes as separator plays important roles in separating cathode and anode, storing electrolytes, and transporting ions in energy storage devices. Here, an effective strategy is reported to prepare an electrolyte superwetting membrane, which shows good Li transport rate and uniformity, as well as electrode-friendly properties to afford the reduction and oxidation of electrodes. It thereby improves the cycle stability and safety of Li metal batteries. With the arrayed capillaries technique, a thin layer of polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN) composite is uniformly coated on the surface and pores of polypropylene (PP) membrane with a total thickness of 30 µm. After treating it with n-butyllithium and LiNO in turn, a chemically inert membrane with efficient and uniform ion transport is prepared, and the cycle stability of Li||Li symmetric cells is up to 1500 h, 4 times higher than that of PP membrane. Moreover, the Li||LiFePO with as-prepared membranes achieve a higher capacity retention rate of 92% after 190 cycles at a current density of 3.6 mA cm and a capacity of 3.6 mAh cm, and the Li||NCM721 batteries achieve a capacity retention rate of 71% after 600 cycles at a current density of 1.8 mA cm.
多孔聚合物膜作为隔膜在储能装置中对分隔正负极、储存电解质以及传输离子起着重要作用。在此，报道了一种制备电解质超润湿性膜的有效策略，该膜显示出良好的锂传输速率和均匀性，以及对电极友好的特性，以实现电极的还原和氧化。从而提高了锂金属电池的循环稳定性和安全性。采用阵列毛细管技术，将一层厚度为30 µm的聚偏氟乙烯（PVDF）和聚丙烯腈（PAN）复合材料均匀涂覆在聚丙烯（PP）膜的表面和孔中。依次用正丁基锂和LiNO处理后，制备出具有高效且均匀离子传输的化学惰性膜，Li||Li对称电池的循环稳定性高达1500 h，是PP膜的4倍。此外，使用所制备的膜的Li||LiFePO在电流密度为3.6 mA cm²、容量为3.6 mAh cm²的条件下循环190次后，实现了92%的更高容量保持率，Li||NCM721电池在电流密度为1.8 mA cm²的条件下循环600次后，容量保持率达到71%。
