For a room temperature operation of fluoride ion secondary batteries, it is strongly demanded for a development of fast fluoride ion conductors. Potassium tetrafluoroantimonate (KSbF₄) is an air stable crystalline F⁻ ion conductor that can be synthesized by a liquid phase method. Taking account for the effects of lattice defects in ion conductive crystals, we elucidate and propose that a heat treatment just below the melting temperature (550 K) introduces significant amounts of lattice defects in β-KSb_1-δF_4-3δ (δ = 0.54), which drastically increases the F⁻ ion conductivity. The F⁻ ion conductivity of the material is now reached into the order of 10⁻⁴ S cm⁻¹ at room temperature and 10⁻² S cm⁻¹ at 420 K, which are two orders of magnitude higher than those in the sintering at 490 K. Spectroscopic analyses revealed that, during the heat treatment, SbF₃ evaporates from the bulk with retaining the lattice framework, suggesting that a number of vacancies at Sb (54%) and F (41%) atomic sites remarkably promote the F⁻ ion diffusivity in β-KSb_1-δF_4-3δ polycrystals. The present heat treatment method just below the melting point should be applicable to improve the F⁻ ion conductivity of complex salt fluorides.

对于氟离子二次电池的室温操作，强烈需要开发快速的氟离子导体。钾tetrafluoroantimonate（KSbF ₄）是空气稳定的结晶˚F ^-可通过液相法来合成离子导体。考虑为晶格缺陷的离子导电性晶体的影响，我们阐明和建议热处理刚好低于熔化温度（550 K）引入显著量晶格缺陷在β-KSB _1-δ ˚F _4-3δ（δ= 0.54），其显着地增加了在F ^-离子传导性。在F ^-的材料的离子传导性现已达到成10顺序^-4 小号厘米^-1在室温和10 ^-2 小号厘米^-1，在420 K，这是两个数量级比在490 K.光谱烧结分析显示高于，在热处理过程中，的SbF _3个从本体与蒸发保持晶格骨架，这表明在锑（54％）和F（41％）的数空位原子位点显着地促进在F ^-离子扩散在β-KSB _1-δ ˚F _4-3δ多晶体。本热处理方法只是低于熔点应适用于改善在F ^-配盐氟化物离子传导性。