Liu Shixiang, Liu Qiang, Cheng Pu, Jia Xingkai, Jiang Yinzhu, Zhang Xuan
ZJU‑Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, P. R. China.
School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China.
Adv Sci (Weinh). 2025 Jul;12(25):e2501155. doi: 10.1002/advs.202501155. Epub 2025 Apr 1.
Lithium metal batteries (LMBs) have gained significant attention because of their high theoretical energy density. However, under high-rate charge and discharge conditions, lithium metal anodes are susceptible to dendrite formation, compromising battery safety. Creating multifunctional separators offers an effective and cost-efficient solution for addressing fast charging and safety challenges in LMBs. This study proposes a method to prepare a functional separator by in situ growing a polydopamine copper chelate (PDA(Cu)) coating on a polypropylene (PP)/polyethylene (PE)/PP separator (PP/PE/PP@PDA(Cu)). The PDA(Cu) exhibits excellent electrolyte wetting properties and ion exclusion effects, contributing to high ionic conductivity (5.02 × 10⁴ S cm) and high lithium-ion (Li) transference number (0.776). Owing to its strong adhesion to the lithium metal anode, the coating significantly suppresses the formation of lithium dendrites. The Li||Li symmetric cell with a PP/PE/PP@PDA(Cu) separator demonstrates highly stable lithium plating-stripping cycles, lasting over 900 h. Additionally, the PDA(Cu) promotes the formation of a stable cathode electrolyte interphase (CEI) film on the LiFePO cathode surface. The LiFePO||Li cell with a PP/PE/PP@PDA(Cu) separator maintains 85.1% of its capacity after 6000 cycles at 10 C. This work paves a novel path for designing separators to enhance the fast-charging performance of LMBs and solve the challenges of lithium dendrite formation and long cycling life.
锂金属电池（LMBs）因其高理论能量密度而备受关注。然而，在高倍率充放电条件下，锂金属负极容易形成枝晶，危及电池安全。制备多功能隔膜为解决LMBs的快速充电和安全挑战提供了一种有效且经济高效的解决方案。本研究提出了一种在聚丙烯（PP）/聚乙烯（PE）/PP隔膜（PP/PE/PP@PDA（Cu））上原位生长聚多巴胺铜螯合物（PDA（Cu））涂层来制备功能隔膜的方法。PDA（Cu）具有优异的电解质润湿性和离子排斥效应，有助于实现高离子电导率（5.02×10⁻⁴ S cm）和高锂离子（Li）迁移数（0.776）。由于其对锂金属负极具有很强的附着力，该涂层显著抑制了锂枝晶的形成。采用PP/PE/PP@PDA（Cu）隔膜的Li||Li对称电池展示出高度稳定的锂电镀-剥离循环，持续时间超过900小时。此外，PDA（Cu）促进了在LiFePO₄ 正极表面形成稳定的正极电解质界面（CEI）膜。采用PP/PE/PP@PDA（Cu）隔膜的LiFePO₄||Li电池在10 C下经过6000次循环后仍保持其容量的85.1%。这项工作为设计隔膜以提高LMBs的快速充电性能以及解决锂枝晶形成和长循环寿命的挑战开辟了一条新途径。
