Fast fluoride ion conduction of NH4(Mg1-xLix)F3-x and (NH4)2(Mg1-xLix)F4-x assisted by molecular cations
Kota Motohashi, Yosuke Matsukawa, Takashi Nakamura, Yuta Kimura, Naoaki Kuwata, Yoshiharu Uchimoto, Koji Amezawa
Abstract
Abstract Aiming development of the fast anion conductors, we proposed a new material design using flexible molecular cation as a host cation, and demonstrated it with fluoride ion conduction in NH 4 MgF 3 and (NH 4 ) 2 MgF 4 based materials. Dominant fluoride ion conduction with relatively high conductivities of 4.8 × 10 –5 S cm −1 and 8.4 × 10 –6 S cm −1 were achieved at 323 K in (NH 4 ) 2 (Mg 0.85 Li 0.15 )F 3.85 and NH 4 (Mg 0.9 Li 0.1 )F 2.9 , respectively. It is implied that the molecular cation in the host lattice can assist the anion conduction. Our findings suggest molecular cation-containing compounds can be attractive material groups for fast anion conductors.