1~10莫耳百分比氧化錫添加之氧化鉍作為固態電解質之研究

Abstract

本研究添加少量(＜10 mol%)二氧化錫至氧化鉍中，以膠粒製程與固態反應法合成並進行性質分析。研究目的包括了解添加二氧化錫對於氧化鉍的導電性質、抗還原性質的影響，並釐清既有氧化鉍－二氧化錫相圖彼此間的相異之處。X光繞射儀與熱差分析儀被用於研究添加二氧化錫之氧化鉍(BSO)樣品的相變行為，此外進行了密度量測、掃描式電子顯微鏡觀察、兩點電極電性量測以及重量損失實驗，以測試BSO樣品的性質。由分析結果重新繪製了新的氧化鉍－二氧化錫相圖。BSO樣品基本上為α相氧化鉍與錫酸鉍(Bi2Sn2O7)的雙相混合樣品，唯有添加1 mol%二氧化錫(1BSO)的樣品在燒結後形成介穩定的α-氧化鉍單一相。而1BSO也是導電性表現最好的BSO樣品，其於600oC的導電性為7.74×10-5 S/cm，而在650oC的導電性為1.78×10-4 S/cm。此外，在650oC、氧分壓為10-16 atm的還原氣氛下，1BSO樣品在80分鐘內仍保持氧化態不被還原。

Various Bi2O3 materials (BSO) doped with SnO2 up to 10 mol% have been synthesized by colloidal process and solid state reactions. The objectives are to study the effect of SnO2 dopant on the electrical conductivity and the stability of the BSO materials in reducing atmosphere. The discrepancies existing between the reported Bi2O3-SnO2 phase diagrams are also investigated. X-ray diffraction (XRD) and differential thermal analyzer (DTA) are used to investigate the phase transition behaviors of the BSO samples. Archimedes’ method, XRD, scanning electron microscope (SEM) observation, 2-probe conductivity measurement and mass loss test are used to study the properties of the samples. A revised Bi2O3-SnO2 phase diagram of 0~10 mol% SnO2 region is proposed. Most of sintered BSO samples consist of α-Bi2O3 and Bi2Sn2O7 phases. While the sintered 1 mol% SnO2-doped Bi2O3 (1BSO) is dense and shows single phase α-Bi2O3. The highest electrical conductivity at the range of 450~700oC were obtained by 1BSO sample, which was 7.74×10-5 S/cm at 600oC and 1.78×10-4 S/cm at 650oC. The most noteworthy advantage of SnO2-dopant is that it stabilizes the Bi2O3 matrix in reducing atmosphere in which the oxygen partial pressure is 10-16 atm (controlled by CO/CO2) at 650oC.