Xia Qingchun, Han Kaixin, Ma Xuxiao, Qiu Pengtao, Li Zhiyong, Chen Xuenian
Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
College of Chemistry, Zhengzhou University Zhengzhou 450001 China.
Chem Sci. 2024 Oct 7;15(42):17579-89. doi: 10.1039/d4sc02861a.
Tetraphenylborate (BPh ) has been widely employed in the field of electrolytes and displayed better ionic conductivities in polymer solid-state Li conductors. However, the fabrication of tetraphenylborate monomers into metal-organic frameworks (MOFs) and the exploration of their potential in solid-state electrolytes have never been reported. In this work, carboxylic acid functionalized lithium tetraphenylborate was purposefully synthesized and employed to construct an anionic MOF as a solid electrolyte. The counter cation Li was encapsulated into the anionic channel to become the free mobile charge carrier that produced a lithium-ion solid electrolyte with outstanding ion conductivity (2.75 × 10 S cm at 25 °C), an impressively high lithium-ion transference number ( = 0.89), and low activation energy (0.15 eV). Acting as a solid electrolyte, the anionic MOF-based lithium iron phosphate battery delivered an initial specific capacity of 135 mA h g and retained 95% capacity after 220 charge-discharge cycles with a coulombic efficiency close to 100%. Moreover, by exchanging the free Li with Na, K, Mg, Ca, and Zn, our anionic MOF is also available for other types of solid electrolytes with the corresponding conductivities all above that of the functional battery electrolyte. Our work provided a convenient and tunable route to prepare conducting MOFs for alkali metal ions, alkaline earth metal ions, and other possible metal cations of interest, which could be used in solid-state electrolytic devices in the future.
四苯基硼酸盐（BPh ）已在电解质领域得到广泛应用，并在聚合物固态锂导体中表现出更好的离子电导率。然而，将四苯基硼酸盐单体制备成金属有机框架（MOF）及其在固态电解质中的潜力探索尚未见报道。在这项工作中，有目的地合成了羧酸功能化的四苯基硼酸锂，并用于构建一种阴离子型MOF作为固体电解质。抗衡阳离子Li被封装在阴离子通道中成为自由移动的电荷载体，从而产生了一种具有出色离子电导率（25℃时为2.75×10 S cm ）、令人印象深刻的高锂离子迁移数（ = 0.89）和低活化能（0.15 eV）的锂离子固体电解质。基于阴离子MOF的磷酸铁锂电池作为固体电解质，初始比容量为135 mA h g ，在220次充放电循环后容量保留95%，库仑效率接近100%。此外，通过用Na、K、Mg、Ca和Zn交换自由Li，我们的阴离子MOF还可用于其他类型的固体电解质，其相应电导率均高于功能性电池电解质。我们的工作提供了一种方便且可调节的途径来制备用于碱金属离子、碱土金属离子和其他可能感兴趣的金属阳离子的导电MOF，未来可用于固态电解装置。
