Proton Conduction Mechanism for Anhydrous Imidazolium Hydrogen Succinate Based on Local Structures and Molecular Dynamics
Proton Conduction Mechanism for Anhydrous Imidazolium Hydrogen Succinate Based on Local Structures and Molecular Dynamics
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DOI：
10.1021/acs.jpclett.1c01280
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发表时间：
2021-06-03
影响因子：
5.7
通讯作者：
Shigeta, Yasuteru
中科院分区：
文献类型：
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作者：
Hori, Yuta;Dekura, Shun;Shigeta, Yasuteru
引入咪唑鎓琥珀酸氢盐（Im-Suc）的无水有机结晶材料即使在高于100 ℃的温度下也表现出高质子传导性，对于阐明质子传导机制以开发用于燃料电池的固体电解质是有吸引力的。在此，使用量子化学计算从Im-Suc中的氢键（H-键）变化和限制分子旋转方面研究质子传导机制。用振动频率分析表征了质子传导的局部氢键结构，并与相应的实验数据进行了比较。计算的势能面涉及质子转移（PT）和咪唑（Im）的旋转运动表明，在Im和琥珀酸之间的PT是一个限速步骤的质子运输Im-Suc和质子传导进行通过连续耦合的PT和Im的旋转运动的基础上Grotthuss型机制。这些研究结果提供了分子水平的见解质子传导机制IM为基础的（或纳入）氢键有机质子导体。
Anhydrous organic crystalline materials incorporating imidazolium hydrogen succinate (Im-Suc), which exhibit high proton conduction even at temperatures above 100 degrees C, are attractive for elucidating proton conduction mechanisms toward the development of solid electrolytes for fuel cells. Herein, quantum chemical calculations were used to investigate the proton conduction mechanism in terms of hydrogenbonding (H-bonding) changes and restricted molecular rotation in Im-Suc. The local H-bond structures for proton conduction were characterized by vibrational frequency analysis and compared with corresponding experimental data. The calculated potential energy surface involving proton transfer (PT) and imidazole (Im) rotational motion showed that PT between Im and succinic acid was a rate-limiting step for proton transport in Im-Suc and that proton conduction proceeded via the successive coupling of PT and Im rotational motion based on a Grotthuss-type mechanism. These findings provide molecular-level insights into proton conduction mechanisms for Im-based (or-incorporated) H-bonding organic proton conductors.