Mechanical synthesis and structural properties of the fast fluoride-ion conductor PbSnF4
Mechanical synthesis and structural properties of the fast fluoride-ion conductor PbSnF4
复制标题
DOI：
10.1016/j.jssc.2017.06.007
复制
发表时间：
2017-09-01
影响因子：
3.3
通讯作者：
Fukunaga, Toshiharu
中科院分区：
文献类型：
--
作者：
Fujisaki, Fumika;Mori, Kazuhiro;Fukunaga, Toshiharu
采用机械球磨法合成了氟离子导体γ-PbSnF 4。此外，通过对γ-PbSnF_4进行473 K时效处理，得到β-PbSnF_4。在298 K时，β-PbSnF 4的电导率相对高于γ-PbSnF 4。使用中子衍射数据进行γ-和β-PbSnF 4的晶体结构分析。从所获得的占位符中，氟离子位于γ-PbSnF 4中的F-γ（1）正常位点（62%）和F-γ（2）间隙位点（38%）以及β-PbSnF 4中的F-β（1）正常位点（31%）、F-β（2）正常位点（25%）和F-β（3）间隙位点（44%）。特别是，在γ-β相变后，F间隙位点的氟离子数量增加：F-γ（2）为38%，F-β（3）为44%。最有可能的是，在β-PbSnF 4中氟离子的“-F-beta（1）-F-beta（3）-F-beta（3）-F-beta（1）-”传导路径中，氟离子与空位的比率（或有效载流子浓度）被优化。
A fluoride-ion conductor, gamma-PbSnF4, was synthesized by the mechanical milling. In addition,)beta-PbSnF4 was obtained by aging the gamma-PbSnF4 at 473 K. The electrical conductivity of beta-PbSnF4 is relatively higher than that of gamma-PbSnF4 at 298 K. The crystal structure analysis of gamma- and beta-PbSnF4 was carried out using neutron diffraction data. From the obtained occupancies, fluoride ions were located at the F-gamma(1) normal site (62%) and F-gamma(2) interstitial site (38%) in gamma-PbSnF4 and the F-beta(1) normal site (31%), F-beta(2) normal site (25%), and F-beta(3) interstitial site (44%) in beta-PbSnF4. In particular, the number of fluoride ions at the F interstitial site increased after the gamma-to-beta phase transition: 38% at F-gamma(2) to 44% at F-beta(3). It is most likely that the ratio of fluoride ions to vacancies (or the effective carrier concentration) was optimized in the "-F-beta(1)-F-beta(3)-F-beta(3)-F-beta(1)-" conduction pathways of fluoride ions in beta-PbSnF4.