Jia Huanhuan, Liu Jingjing, Liu Boling, Kuphal Robert, Mottini Vittorio, Monday Paul, Ball Madelyn, Li Jinxing, Nejad Mojgan, Fang Chengcheng
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, 48824, USA.
Department of Biomedical Engineering and Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, 48824, USA.
Adv Mater. 2025 May;37(19):e2419694. doi: 10.1002/adma.202419694. Epub 2025 Mar 26.
Separators are critical components in lithium-ion batteries (LIBs), preventing internal short circuits, mitigating thermal runaway, and influencing rate capability and cycling performance. However, current polyolefin separators suffer from limitations, such as high thermal shrinkage, relatively poor wettability, and inadequate long-term stability, impacting safety and cycle life in critical applications like electric vehicles. Here, a single-layer lignin-based ultrathin separator (as thin as 15 µm) with exceptional intrinsic thermal stability and cycling performance is demonstrated. The separator is fabricated using lignosulfonate, a natural polymer derived as a byproduct of chemical pulping and biorefinery processes. By employing a dry fibrillation method, the process achieves low energy consumption and a 100% raw material conversion rate, highlighting its scalability and sustainability. Interfacial studies reveal the improved cycling performance in both graphite||NMC811 and Si-Gr||NMC811 cells is attributed to the abundant sulfonate functional groups in lignosulfonates, which promote the formation of a sulfur-rich cathode/solid electrolyte interphases (CEI/SEI) with low resistance in both the cathode and anode. The high thermal stability, manufacturing feasibility, battery performance, and low cost of such lignin-based separators offer new inspiration for developing next-generation, single-layer functional separators tailored for high-performance LIBs.
隔膜是锂离子电池（LIBs）中的关键组件，可防止内部短路、减轻热失控，并影响倍率性能和循环性能。然而，目前的聚烯烃隔膜存在局限性，如高热收缩率、相对较差的润湿性和不足的长期稳定性，影响了电动汽车等关键应用中的安全性和循环寿命。在此，展示了一种具有卓越固有热稳定性和循环性能的单层木质素基超薄隔膜（薄至15 µm）。该隔膜是使用木质素磺酸盐制造的，木质素磺酸盐是化学制浆和生物精炼过程的副产品衍生出的天然聚合物。通过采用干法原纤化方法，该工艺实现了低能耗和100%的原料转化率，突出了其可扩展性和可持续性。界面研究表明，石墨||NMC811和Si-Gr||NMC811电池中循环性能的改善归因于木质素磺酸盐中丰富的磺酸酯官能团，这些官能团促进了在阴极和阳极中形成具有低电阻的富硫阴极/固体电解质界面（CEI/SEI）。这种木质素基隔膜的高热稳定性、制造可行性、电池性能和低成本为开发适用于高性能LIBs的下一代单层功能隔膜提供了新的灵感。
