Xu Shen, Naren Tuoya, Zhao Yanwei, Gu Qianfeng, Wai Lau Ting, Lee Chun-Sing, Chen Fu-Rong, Yin Jun, Chen Libao, Zhang Qichun
Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, 999077, P. R. China.
State Key Laboratory of Flexible Electronics & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, P. R. China.
Angew Chem Int Ed Engl. 2025 Apr 7;64(15):e202422040. doi: 10.1002/anie.202422040. Epub 2025 Feb 7.
Lithium metal batteries (LMBs) are regarded as the potential alternative of lithium-ion batteries due to their ultrahigh theoretical specific capacity (3860 mAh g). However, severe instability and safety problems caused by the dendrite growth and inevitable side reactions have hindered the commercialization of LMBs. To solve them, in this contribution, a design strategy of soluble lithiophilic covalent organic frameworks (COFs) is proposed. By introducing polyethylene glycol as the side chains, two COFs (CityU-28 and CityU-29) not only become soluble for the facile coating technique, but also can facilitate the lithium-ion migration in batteries. Furthermore, when coated on the lithium anode of LMB, both COFs can act as artificial solid electrolyte interphase to prevent dendrite growth thus enabling the long-term stability of the cells. Notably, the symmetric CityU-29@Li cell can work for more than 5000 h at a current density of 2 mA cm and an areal capacity of 1 mAh cm. A remarkable capacity retention of 78.9 % after 1500 cycles and a Coulombic efficiency of about 99.9 % at 1.0 C can also be realized in CityU-29@Li||LiFePO full cell. This work could provide a universal design strategy for soluble COFs and enlighten their application in diverse scenarios, especially energy-related fields.
锂金属电池（LMBs）因其超高的理论比容量（3860 mAh g）而被视为锂离子电池的潜在替代品。然而，枝晶生长和不可避免的副反应所导致的严重不稳定性和安全问题阻碍了LMBs的商业化。为了解决这些问题，在本研究中，提出了一种可溶性亲锂共价有机框架（COFs）的设计策略。通过引入聚乙二醇作为侧链，两种COFs（CityU-28和CityU-29）不仅因便于涂层技术而可溶，而且还能促进电池中的锂离子迁移。此外，当涂覆在LMB的锂阳极上时，两种COFs都可以作为人工固体电解质界面来防止枝晶生长，从而实现电池的长期稳定性。值得注意的是，对称的CityU-29@Li电池在2 mA cm的电流密度和1 mAh cm的面积容量下可工作超过5000小时。在CityU-29@Li||LiFePO全电池中，1500次循环后还可实现78.9%的显著容量保持率和1.0 C时约99.9%的库仑效率。这项工作可为可溶性COFs提供一种通用的设计策略，并启发它们在各种场景中的应用，特别是在与能源相关的领域。
