Zhou Taotao, Tang Wenhao, Lv Junwen, Deng Yirui, Liu Qiang, Zhang Lei, Liu Ruiping
Department of Materials Science and Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, P. R. China.
School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, P. R. China.
Small. 2023 Nov;19(48):e2303924. doi: 10.1002/smll.202303924. Epub 2023 Aug 3.
Commercial polymer separators usually have limited porosity, poor electrolyte wettability, and poor thermal and mechanical stability, which can deteriorate the performance of battery, especially at high current densities. In this work, a functional polyethylene (PE) separator is prepared by surface engineering a layer of Ti-doped SiO @Al O particles (denoted as ST@Al O -PE) with strong Lewis acid property and uniform porous structure on one side of the PE separator. On the other hand, ST@Al O particles with abundant pore structures and large cavities can store a large amount of electrolyte, providing a shortened pathway for lithium-ion transport, and the Lewis acid sites and porous structure of the ST@Al O can tune Li plating/stripping behavior and stabilize the lithium metal anode. The ST@Al O -PE separators exhibit better ionic conductivity (5.55 mS cm ) and larger lithium-ion transference number (0.62). At a current density of 1 mA cm , Li/Li symmetric cells with ST@Al O -PE separator can be stably cycled for more than 400 h, and both lithium iron phosphate /Li cells and lithium cobaltate/Li cells with ST@Al O -PE separator have good cycling and rate performance. This work provides a new strategy for developing functional separators and promoting the application of lithium metal batteries.
商用聚合物隔膜通常孔隙率有限、电解质润湿性差、热稳定性和机械稳定性不佳，这会使电池性能恶化，尤其是在高电流密度下。在本工作中，通过在聚乙烯（PE）隔膜的一侧对具有强路易斯酸性和均匀多孔结构的一层钛掺杂二氧化硅@氧化铝颗粒（记为ST@Al₂O₃-PE）进行表面工程处理，制备了一种功能性聚乙烯隔膜。另一方面，具有丰富孔结构和大孔洞的ST@Al₂O₃颗粒可以储存大量电解质，为锂离子传输提供一条缩短的路径，并且ST@Al₂O₃的路易斯酸位点和多孔结构可以调节锂的沉积/剥离行为并稳定锂金属负极。ST@Al₂O₃-PE隔膜表现出更好的离子电导率（5.55 mS cm⁻¹）和更大的锂离子迁移数（0.62）。在1 mA cm⁻²的电流密度下，采用ST@Al₂O₃-PE隔膜的锂/锂对称电池可以稳定循环超过400小时，并且采用ST@Al₂O₃-PE隔膜的磷酸铁锂/锂电池和钴酸锂/锂电池都具有良好的循环和倍率性能。这项工作为开发功能性隔膜和推动锂金属电池的应用提供了一种新策略。
