The solid state electrolytes show a wide range of practical applications in a variety of all-solid-state electrochemical devices, and it is highly in demand to explore new types of solid state electrolyte materials. In this study, we have designed and prepared a fluorite-type coordination compound, [Mn(en)₃]I₂, which has been characterized by microanalysis for C, H and N elements, infrared spectrum in the wavenumber range of 4000–400 cm⁻¹, thermogravimetric analysis and differential scanning calorimetry. The single crystal X-ray diffraction revealed that the bigger size [Mn(en)₃]²⁺ cations build three-dimensional network in the crystal of [Mn(en)₃]I₂ and the smaller size iodide ions occupy the tetrahedral or octahedral cavities surrounded by the [Mn(en)₃]²⁺ cations, featuring as the fluorite-type compound. The impedance spectra were investigated to reveal the ionic conductivity σ = 3.45 × 10⁻¹¹ S cm⁻¹ at 303 K, while σ = 1.37 × 10⁻⁶ S cm⁻¹ at 423 K, sharply increasing by five orders of magnitude regarding to that at 303 K. The electric modulus analysis further confirmed the conductance contributed from the migration of iodide ions. This study opens a way to design and achieve new coordination compound-based ion conductors.

中文翻译：

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萤石型配位化合物作为碘离子导体：晶体结构与离子电导率

固态电解质在各种全固态电化学装置中显示出广泛的实际应用，并且迫切需要探索新型的固态电解质材料。在这项研究中，我们设计并制备了萤石型配位化合物[Mn（en）₃ ] I ₂，其特征在于通过微量分析C，H和N元素，波谱范围为4000-400的红外光谱cm ^-1，热重分析和差示扫描量热法。X射线单晶衍射表明，较大的[Mn（en）₃ ] ²⁺阳离子在[Mn（en）₃ ] I ₂晶体中建立三维网络。较小的碘离子占据被[Mn（en）₃ ] ²⁺阳离子包围的四面体或八面体腔，为萤石型化合物。对阻抗谱进行了研究，发现在303 K时离子电导率σ = 3.45×10 ^-11 S cm ^-1，而在423 K时σ = 1.37×10 ^-6 S cm ^-1，与电导率相比急剧增加了五个数量级。电模量分析进一步证实了电导率是由碘离子的迁移贡献的。这项研究为设计和实现新的基于配位化合物的离子导体开辟了道路。