Miki Hidenori, Matsunaga Toshiyuki, Li Zhuoran, Cao Zulai, Yamamoto Kentaro, Kumar Mukesh, Thakur Neha, Watanabe Toshiki, Iba Hideki, Kobayashi Shintaro, Kawaguchi Shogo, Ikeda Kazutaka, Hagihala Masato, Kamiyama Takashi, Kuwabara Akihide, Kageyama Hiroshi, Maeda Kazuhiko, Uchimoto Yoshiharu
Toyota Motor Corporation, Advanced Material Engineering Division, Higashifuji Technical Center, 1200 Mishuku, Susono, Shizuoka 410-1193, Japan.
Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan.
Inorg Chem. 2024 Dec 9;63(49):23095-23102. doi: 10.1021/acs.inorgchem.4c02341. Epub 2024 Oct 7.
Structural characteristics on fluoride ion storage and conduction mechanism in LaSrMnO, and its fluoridated materials, LaSrMnOF and LaSrMnOF, for an all-solid-state fluoride ion battery positive electrode with a high volumetric capacity surpassing those of lithium-ion ones have been revealed using the Rietveld method and maximum entropy method. In LaSrMnO, once the F ions are taken into the NaCl slabs in its crystal through the charging process, it forms two stable fluoride compounds, LaSrMnOF and LaSrMnOF, with the help of the Mn oxidation reaction. In these oxyfluorides, thermal vibrations of the F ions inserted are much larger, especially in the - plane, than along the axis. When surplus energy, such as an electric field for charging, is applied to these crystals at near room temperature or higher, the anions immediately begin to jump to their neighboring lattice sites, resulting in sufficiently rapid and large ionic conduction. The MEM analyses and density functional theory (DFT) calculations have revealed that the F ions enable to easily travel along the ⟨110⟩ directions in the NaCl slabs of these crystals. These structural features thus make LaSrMnO and its fluorides possess both of two features incompatible with each other, ion storage and conduction, indispensable for rechargeable batteries.
利用Rietveld方法和最大熵方法揭示了LaSrMnO及其氟化材料LaSrMnOF和LaSrMnOF中氟离子存储和传导机制的结构特征，这些材料用于全固态氟离子电池正极，具有超过锂离子电池的高体积容量。在LaSrMnO中，一旦F离子在充电过程中通过其晶体中的NaCl板层被吸收，它会在Mn氧化反应的帮助下形成两种稳定的氟化物化合物LaSrMnOF和LaSrMnOF。在这些氧氟化物中，插入的F离子的热振动，特别是在平面内，比沿轴方向大得多。当在接近室温或更高温度下向这些晶体施加多余的能量，如充电电场时，阴离子立即开始跳到它们相邻的晶格位置，导致足够快速和大量的离子传导。MEM分析和密度泛函理论（DFT）计算表明，F离子能够在这些晶体的NaCl板层中沿⟨110⟩方向轻松移动。因此，这些结构特征使LaSrMnO及其氟化物具有可充电电池不可或缺的两个相互矛盾的特征，即离子存储和传导。
