Fluoride Ion Conductivity of Rb Doped KSbF4

Abstract

All solid-state fluoride ion batteries are considered to be high energy density and safe energy storage devices. However, the F– ion conductivities of solid electrolytes at room temperature are low (< 10-6 S cm-1), which requires the higher operating temperature of fluoride ion battery such as 420 K or higher. Therefore, the faster F– ion conductors is strongly desired to operate fluoride ion battery at lower or even room temperature. KSbF4 is one of the promising candidates to have a faster F– ion conductivity. To expand F– ion conduction pathways, we doped Rb in KSbF4 and further investigated the compositional dependence of ionic conductivity in K1-xRbxSbF4 system. We found that ionic conductivity strongly depends on the chemical composition and conductivity was maximized at x = 0.15. At room temperature, the F– ion conductivity in the bulk and at the grain boundary of K0.85Rb0.15SbF4 were σbulk = 1.01 × 10-4 S cm-1 and σGB = 4.80 × 10-5 S cm-1, respectively.

La-Al Intermetallic Alloy Anode for Realizing High-Energy Fluoride-Ion Battery

“…[1][2][3][4][5][6][7][8] An all-solidstate fluoride-ion battery is one of the attractive candidates for the next-generation high-energy batteries due to the high theoretical energy density (over 1000 Wh kg -1 ). [9][10][11][12][13][14] While, in the early days, the practical capacities of anodes and cathodes in the fluoride-ion batteries had been considerably lower than 100 mAh g -1 , the cathodes have recently shown improvements in discharge capacities (up to 200-500 mAh g -1 ). [15][16][17][18] However, the capacities of anodes are still one order of magnitude smaller than the cathodes, and moreover, their cycle stabilities are also very low.…”