东北师范大学孙立群团队开发了用于安全锂离子电池增强热性能的多层聚乙烯隔膜。相关研究成果于2024年1月4日发表于国际顶尖学术期刊《颗粒学报》。

隔膜在电池的安全性和性能方面起着重要作用。聚烯烃隔膜由于其优异的性能被广泛应用于商业LIBs中，但其存在严重的热收缩和较差的电解质润湿性。因此，研究人员开发了多层隔膜（ASPESA），通过使用简单且环保的铸造技术在聚乙烯膜的两侧涂覆两层低密度聚乙烯（LDPE）和Al₂O₃薄层。ASPESA隔膜在120°C下具有关闭功能，在185°C下热稳定性增强，热收缩率为1%。

同时，LDPE和Al₂O₃层可以提高电解质的润湿性和电解质的吸收率（407.23%）。多层ASPESA隔膜在LiFePO₄||Li电池中具有优异的循环性能，900次循环后放电容量为144.5 mAh g^-1，高容量保持率为98.9%（与第5次循环相比）。因此，多层ASPESA隔膜作为LIBs中的高安全性隔膜具有巨大的利用潜力。

附：英文原文

Title: Multilayer polyethylene separator with enhanced thermal properties for safe lithium-ion batteries

Author: Ying Jiang, Chen Sun, Feilong Dong, Haiming Xie, Liqun Sun

Issue&Volume: 2024/01/04

Abstract: Separator plays an important part in battery safety and performance. Polyolefin separators are widely used in commercial LIBs owing to their excellent properties, but suffering from serious thermal shrinkage and poor electrolyte wettability. Thus, a multilayer separator (ASPESA) is developed by coating two thin layers of low-density polyethylene (LDPE) and Al2O3 on both sides of polyethylene membrane using a facile and environmentally-friendly casting technique. The ASPESA separator demonstrates a shutdown function at 120 °C and shows enhanced thermal stability under 185 °C with a small thermal shrinkage of 1%. Meanwhile, the LDPE and Al2O3 layers can improve the electrolyte wettability and electrolyte uptake (407.23%). The multilayer ASPESA separator delivers an excellent cycle performance in LiFePO4||Li cells with a discharge capacity of 144.5 mAh g-1 after 900 cycles with a high-capacity retention of 98.9% (compared with the 5th cycle). Therefore, the multilayer ASPESA separator has great utilization potential as a high safety separator in LIBs.

DOI: 10.1016/j.partic.2023.12.017

Source: https://www.sciencedirect.com/science/article/abs/pii/S1674200124000051