کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5150623 1498244 2017 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Influence of lithium oxide excess and alumina on grain boundary resistance of Li6.75La3Zr1.75Nb0.25O12 solid electrolyte
موضوعات مرتبط
مهندسی و علوم پایه شیمی الکتروشیمی
پیش نمایش صفحه اول مقاله
Influence of lithium oxide excess and alumina on grain boundary resistance of Li6.75La3Zr1.75Nb0.25O12 solid electrolyte
چکیده انگلیسی
Lithium oxide excess and powder bed method are conventionally used for synthesis of lithium-conducting solid electrolytes with cubic garnet structure. In this work Li6.75La3Zr1.75Nb0.25O12 garnet was sintered at 1200 °C on alumina and zirconia supports with controlled amount of lithium oxide excess. It was found that the powder bed method did not prevent garnet pellets from alumina contamination. The quantity of aluminum penetrated into samples correlated with the amount of lithium oxide excess added and varied from 0.2 to 0.5 wt%, as indicated by ICP AES. In contrast to alumina, zirconia did not affect chemical composition of the pellets. Taking this into account to avoid any alumina contamination a modified powder bed method was developed. However, non-contaminated samples showed lower density after sintering when compared to contaminated ones. Lithium oxide excess in the samples is likely to react with the alumina with formation of eutectic that melts at 1200 °C. The liquid eutectic phase acts as a sintering aid and promotes densification up to relative densities of 96%. Electrical properties of the pellets were measured by EIS technique. Bulk conductivity of the dense pellets was 5 × 10− 4 S/cm at 25 °C with the activation energy of 0.3 eV and depends on density. Due to grain boundary resistance dc-conductivity of pellets was lower than 10− 8 S/cm at 25 °C with the activation energy of 0.8 eV. Possible reasons of high grain boundary resistance are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Ionics - Volume 299, January 2017, Pages 55-59
نویسندگان
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