Mechanically and Thermally Robust Microporous Copolymer Separators for Lithium Ion Batteries
Mechanically and Thermally Robust Microporous Copolymer Separators for Lithium Ion Batteries
复制标题
DOI：
10.1016/j.electacta.2022.140705
复制
发表时间：
2022-06
影响因子：
6.6
通讯作者：
Alexander J. Manly;W. Tenhaeff
中科院分区：
文献类型：
--
作者：
Alexander J. Manly;W. Tenhaeff
下一代多功能隔膜可以增强锂离子电池的储能、动力和安全性能，但必须易于制造并与现有的卷对卷制造相结合。本研究提出了一种策略，以方便地制备这些隔膜使用紫外光引发聚合诱导相分离（PIPS），其中微孔聚合物隔膜直接从组成单体和碳酸乙烯酯（EC）致孔剂制造。这使得宽的组成设计空间成为可能，因为具有特定化学官能度的共聚单体可以容易地掺入PIPS前体混合物中。为了提高光聚合反应中丙烯酸酯的转化率和力学性能，将1，4-丁二醇二丙烯酸酯（BDDA）与聚乙二醇二丙烯酸酯（PEGDA）进行共聚。通过调整PEGDA和EC的比例，制备了具有高孔隙率（41.3%）和有效离子电导率（2.09 mS cm-1）的隔膜。包含PEGDA对于将弹性模量增加到> 345 MPa是必要的，这是通过卷对卷制造进行电池组装所需的。所有制备的隔膜均显示能够使锂金属/LiNi 0. 5 Mn 0. 3Co 0. 2 O2半电池可逆循环100次。传统聚烯烃隔板在160 °C下熔化，在高温下收缩高达29.8%，与之不同的是，PIPS隔板具有卓越的、增强安全性的热机械性能，不会发生相变或热收缩。
Next generation, multifunctional separators can enhance energy storage, power, and safety performance of lithium ion batteries but must be simple to fabricate and incorporate with existing roll-to-roll manufacturing. This study presents a strategy to facilely prepare these separators using UV-initiated polymerization-induced phase separation (PIPS), wherein microporous polymer separators are fabricated directly from constituent monomers and ethylene carbonate (EC) porogen. This enables a wide compositional design space as co-monomers with specific chemical functionality can be readily incorporated into the PIPS precursor mixture. Herein, 1,4-butanediol diacrylate (BDDA) was copolymerized with poly(ethylene glycol) diacrylate (PEGDA) to increase the acrylate conversion in the photopolymerization and improve mechanical properties. By tuning the ratio of PEGDA and EC, separators with high porosity (41.3%) and effective ionic conductivity (2.09 mS cm−1) were prepared. Inclusion of PEGDA was essential to increasing the elastic modulus to > 345 MPa, which is required for cell assembly by roll-to-roll manufacturing. All separators prepared were shown to enable reversible cycling of lithium metal/LiNi0.5Mn0.3Co0.2O2half-cells for 100 cycles. Unlike conventional polyolefin separators, which were shown to melt at 160 °C and shrink by up to 29.8% at elevated temperatures, the PIPS separators possess exceptional, safety-enhancing thermomechanical properties, undergoing no phase transitions or thermal shrinkage.