Liu Shaopeng, Cheng Sha, Huang Cheng, Han Jin, Xie Jingjing, Zhang Pengchao, You Ya, Chen Wen, Fu Zhengyi
Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China.
Sanya Science and Education Innovation Park, Wuhan University of Technology, Sanya, 572024, China.
Small. 2024 Dec;20(49):e2404639. doi: 10.1002/smll.202404639. Epub 2024 Sep 12.
Developing high-safety separators is a promising strategy to prevent thermal runaway in lithium-ion batteries (LIBs), which stems from the low melting temperatures and inadequate modulus of commercial polyolefin separators. However, achieving high modulus and thermal stability, along with uniform nanopores in these separators, poses significant challenges. Herein, the study presents ultrathin nanoporous aramid nanofiber (ANF) separators with high modulus and excellent thermal stability, enhancing the safety of LIBs. These separators are produced using a microfluidic-based continuous printing strategy, where the flow thickness can be meticulously controlled at the micrometer scale. This method allows for the continuous fabrication of nanoporous ANF separators with thicknesses ranging from 1.6 ± 0.1 µm to 2.7 ± 0.1 µm. Thanks to the double-side solvent diffusion, the separators exhibit controllably uniform pore sizes with a narrow distribution, spanning from 40 ± 5 nm to 105 ± 9 nm, and a high modulus of 3.3 ± 0.5 GPa. These nanoporous ANF separators effectively inhibit lithium dendrite formation, resulting in a high-capacity retention rate for the LIBs (80% after 240 cycles). Most notably, their robust structural and mechanical stability at elevated temperatures significantly enhances LIB safety under transient thermal abuse conditions, thus addressing critical safety concerns associated with LIBs.
开发高安全性隔膜是防止锂离子电池（LIBs）热失控的一种很有前景的策略，这是由于商用聚烯烃隔膜的低熔点温度和不足的模量所致。然而，要在这些隔膜中实现高模量和热稳定性以及均匀的纳米孔，面临着重大挑战。在此，该研究展示了具有高模量和优异热稳定性的超薄纳米多孔芳纶纳米纤维（ANF）隔膜，提高了锂离子电池的安全性。这些隔膜是采用基于微流体的连续印刷策略生产的，其中流动厚度可以在微米尺度上精确控制。这种方法允许连续制造厚度范围为1.6±0.1 µm至2.7±0.1 µm的纳米多孔ANF隔膜。由于双面溶剂扩散，隔膜呈现出可控的均匀孔径，分布狭窄，范围从40±5 nm至105±9 nm，以及3.3±0.5 GPa的高模量。这些纳米多孔ANF隔膜有效地抑制了锂枝晶的形成，导致锂离子电池具有高容量保持率（240次循环后为80%）。最值得注意的是，它们在高温下强大的结构和机械稳定性显著提高了锂离子电池在瞬态热滥用条件下的安全性，从而解决了与锂离子电池相关的关键安全问题。
