南开大学焦丽芳团队报道了MOF改性固态聚合物电解质的竞争配位和双界面调节，用于高性能钠金属电池。相关研究成果发表在2025年1月9日出版的国际学术期刊《德国应用化学》。

固态聚合物电解质（SPEs）因其增强的柔韧性和降低界面电阻，而成为固态钠金属电池（SMBs）的突出候选者。然而，它们的性能受到室温下Na⁺电导率低、离子输运性质无序和界面不稳定的限制。

该文中，研究人员将聚丙烯腈（PAN）纤维上的三维（3D）互连铜金属有机框架（Cu-MOF），引入聚环氧乙烷（PEO）基SPE中s，以构建复合电解质（PPNM）。Cu-MOF的开放金属位点（OMS）与Na⁺竞争，有效地与PEO中的TFSI^-阴离子和氧原子配位，从而减少浓差极化，削弱Na⁺-O结合强度，促进Na⁺迁移。

通过利用Cu-MOF和PAN的多功能特性，PPNM电解质在室温下表现出优异的离子电导率（1.03×10^-4Scm^-1）和较高的Na⁺转移数（0.58）。Cu-MOF对TFSI阴离子的强锚定，促进了富含无机物（NaF和Na₃N）的阴极电解质界面（CEI）和固体电解质界面（SEI）层的形成，增强了双重界面稳定性。Na₃V₂（PO₄）₃@C/PPNM/Na全电池在200 mA g^–1下实现了2000次循环的稳健循环性能。

该项工作为调节固态SMBs中的Na⁺配位状态和相间工程，提供了一种简便的策略。

附：英文原文

Title: Competitive Coordination and Dual Interphase Regulation of MOF-Modified Solid-State Polymer Electrolytes for High-Performance Sodium Metal Batteries

Author: Wenyue Tian, Guangliang Lin, Shaohui Yuan, Ting Jin, Qinglun Wang, Lifang Jiao

Issue&Volume: 2025-01-09

Abstract: Solid-state polymer electrolytes (SPEs) have emerged as prominent candidates for solid-state sodium metal batteries (SMBs) due to their enhanced flexibility and reduced interfacial resistance. However, their performance is limited by poor Na+ conductivity at room temperature, disordered ion transport properties and unstable interfaces. Herein, a three-dimensional (3D) interconnected copper metal organic framework (Cu-MOF) on polyacrylonitrile (PAN) fibers is introduced into polyethylene oxide (PEO)-based SPEs to construct a composite electrolyte (PPNM). The open metal sites (OMS) of the Cu-MOF compete with Na+, effectively coordinating with TFSI– anions and oxygen atoms in PEO, thereby reducing concentration polarization, weakening the Na+-O binding strength and facilitating Na+ migration. By harnessing the multifunctional properties of Cu-MOF and PAN, the PPNM electrolyte exhibits superior ionic conductivity (1.03×10–4 S cm–1) and a high Na+ transference number (0.58) at room temperature. The strong anchoring of TFSI– anions by Cu-MOF promotes the formation of inorganic-rich (NaF and Na3N) cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) layers, enhancing dual interfacial stability. The Na3V2(PO4)3@C/PPNM/Na full cells realize robust cycling performance for 2000 cycles at 200 mA g–1. This work provides a facile strategy for regulating the Na+ coordination state and interphase engineering in solid-state SMBs.

DOI: 10.1002/anie.202423075

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202423075