Lim Dae-Woon, Kitagawa Hiroshi
Department of Chemistry and Medical Chemistry, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwondo 26493, Republic of Korea.
Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
Chem Rev. 2020 Aug 26;120(16):8416-8467. doi: 10.1021/acs.chemrev.9b00842. Epub 2020 May 14.
Solid-state proton conductors (SSPCs), which are a key component for the safety and efficiency of fuel cells, have received much attention due to their broad application in electrochemical devices. In particular, the development of new materials with high conducting performance and an understanding of the conduction mechanism have become critical issues in this field. Porous metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have recently emerged and have been extensively studied as a new type of proton conductor due to their crystallinity, designability, and high porosity. These properties are able to adsorb the guest molecules working as conducting media. During the past decade, major advances in proton-conductive MOFs have been achieved with high performance (>10 S cm), comparable to the conventional material, via various synthetic strategies, and the veiled conduction mechanism has been elucidated through structure analysis and spectroscopy tools such as NMR, X-ray diffraction, and neutron scattering measurement. This Review aims to summarize and provide a comprehensive understanding of proton transport in MOFs. Here, we discuss the fundamental principles and various design strategies and implementations aimed at enhancing proton conductivity with representative examples. We also deal with characterization methods used to investigate proton-conductive MOFs and computational/theoretical studies that aid in understanding the conduction mechanism. Finally, future endeavors are suggested regarding the challenges of research for practical SSPCs.
固态质子导体（SSPCs）是燃料电池安全性和效率的关键组成部分，因其在电化学装置中的广泛应用而备受关注。特别是，开发具有高导电性能的新材料以及理解传导机制已成为该领域的关键问题。多孔金属有机框架（MOFs）或多孔配位聚合物（PCPs）最近出现，并因其结晶性、可设计性和高孔隙率而作为一种新型质子导体得到广泛研究。这些特性能够吸附充当传导介质的客体分子。在过去十年中，通过各种合成策略，质子传导性MOFs取得了重大进展，其高性能（>10 S cm）与传统材料相当，并且通过诸如核磁共振（NMR）、X射线衍射和中子散射测量等结构分析和光谱工具阐明了隐藏的传导机制。本综述旨在总结并全面理解MOFs中的质子传输。在此，我们讨论基本原则以及旨在提高质子传导率的各种设计策略和实施方法，并给出代表性示例。我们还涉及用于研究质子传导性MOFs的表征方法以及有助于理解传导机制的计算/理论研究。最后，针对实用SSPCs研究面临的挑战提出了未来的努力方向。
