Presentation Information
[10p-E202-13]Systematic Materials Exploration of Lanthanide-Based Fluoride Single Crystals for the Practical Application of Fluoride Electrolytes
〇Kei Kamada1,2,3, Kunimitsu Kataoka4, Hideaki Iwasawa5, Dorai Arunkumar6, Masahito Ichinohe3, Kyoung Jim Kim1,3, Rikito Murakami1,2, Shiika Itoi3, Akira Yoshikawa1,2,3 (1.NICHe, Tohoku Univ., 2.IMR, Tohoku Univ., 3.C&A, 4.AIST, 5.QST, 6.IMRAM, Tohoku Univ.)
Keywords:
Fluoride-ion battery,,Solid electrolyte,Lanthanide fluoride single crystal
Lanthanide-based fluoride single crystals, (R1−xAEx)F3−x (R = La, Ce, Nd, Pr, Tb, Dy, and Ho; AE = Ca, Sr, and Ba), were systematically grown by the micro-Bridgman–Stockbarger method as solid electrolytes for fluoride-ion batteries. Their ionic conductivity, composition, crystal structure, oxygen impurity states, and F− mobility were evaluated by AC impedance spectroscopy, EPMA, single-crystal X-ray diffraction, XPS, and temperature-dependent NMR. AE substitution enhanced the room-temperature ionic conductivity by one to two orders of magnitude, and CeF3-based crystals exhibited conductivities in the 10−3 S cm−1 range. NMR measurements confirmed fluoride-ion motion, while XPS suggested a correlation between oxygen impurity states and conductivity. The relationships among growth conditions, crystal structure, impurity chemistry, and fluoride-ion transport will be discussed.