The separator, an essential component in lithium ion batteries, faces more challenges with the increasing diversification of electrode materials towards higher energy density and longer life. Herein we report the performance improvements of lithium ion batteries enabled by the multifunctional separator, which is fabricated by constructing the silica-oxygen-borate (Si–O–B) thin layer on Al₂O₃-coated polyethylene separators through surface engineering. This separator inherits the advantage of Al₂O₃-coated polyethylene separators in terms of excellent thermal stability and puncture strength, and no obvious dimensional change at 200 °C. The Si–O–B thin layer provides abundant Lewis acid sites and excellent electrolyte uptake to desolvate Li⁺ ions and traps anions, and therefore favors excellent lithium ion transport properties and lithium/electrolyte interfacial stability. More importantly, the Si–O–B hybrid thin layer endows an additional function of scavenging HF and H₂O molecules. The benefits offered by this separator are demonstrated by the enhanced C-rates capability and cycling performance of both LiCoO₂/Li half-cell and NCM/graphite full cell, which lies far beyond those achievable with commercial polyethylene separators and Al₂O₃-coated polyethylene separators. This work presents a simple and efficient strategy to construct multifunctional separators with excellent comprehensive properties, and provides inspiration for the rational design of advanced separators towards next-generation high-performance batteries.

隔膜是锂离子电池的重要组成部分，随着电极材料多样化的发展，朝向更高的能量密度和更长的寿命，面临着更多的挑战。在这里，我们报告了通过多功能隔板实现的锂离子电池性能的提高，该多功能隔板是通过在Al ₂ O ₃涂层的聚乙烯隔板上通过表面工程构造硅氧硼酸（Si–O–B）薄层而制成的。该隔膜继承了Al ₂ O ₃的优点涂层的聚乙烯隔膜具有出色的热稳定性和穿刺强度，并且在200°C下尺寸没有明显变化。Si–O–B薄层提供丰富的路易斯酸位点和出色的电解质吸收能力，以使Li ⁺离子去溶剂化并捕获阴离子，因此有利于出色的锂离子传输性能和锂/电解质界面稳定性。更重要的是，Si–O–B杂化薄层具有清除HF和H ₂ O分子的附加功能。LiCoO ₂ / Li半电池和NCM /石墨全电池的增强的C速率能力和循环性能证明了这种隔膜提供的好处，这远远超出了商用聚乙烯隔膜和Al ₂所能达到的那些O ₃涂层的聚乙烯隔膜。这项工作提出了一种构建具有优异综合性能的多功能隔板的简单有效策略，并为合理设计下一代高性能电池的先进隔板提供了灵感。