水熱合成Bi1-XNbXO1.5+δ粉體與其特性之研究

Characterization of Bi1-XNbXO1.5+δ Powders by Hydrothermal Synthesis

許秀慧(Xiu-Hui Hsu)

指導教授 ： 王錫福 ； 吳玉娟

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2010年)

摘要

本研究為探討中溫型(500∼800oC)固態氧化物燃料電池(solid oxide fuel cell, SOFC)之電解質以取代傳統所使用的YSZ（yttria stabilized zirconia）。操作溫度範圍在500∼800oC內，YSZ的氧離子導電度非常低，故本研究將以氧化鉍(Bi¬2O3)系統為研究重心。
在本研究中，水熱反應前驅物為硝酸鉍、氧化鈮，藉由改變礦化劑於前驅物溶液中之濃度、反應溫度和持溫時間等參數，成功的合成出Bi1-XNbXO1.5+δ (X = 0.25、0.28、0.35、0.45、0.54)系列之奈米級粉末，將試片進行XRD繞射分析、SEM微觀分析及四線式電阻量測分析，由SEM微觀分析下發現水熱合成後之粉末為球形，能有效控制其粉體形貌，粒徑約為80~100 nm，XRD分析出其為Bi3NbO7單一立方螢石結構，Bi0.79Nb0.21O1.5+δ粉末經過壓胚、燒結後之試片，在燒結條件為800oC、持溫2 小時下，利用四線式電阻量測其導電率，發現在800oC操作溫度之下，其導電率為0.35 Scm-1。

關鍵字

固態氧化物燃料電池 ； 電解質 ； 水熱合成法 ； 氧化鉍

並列摘要

The aim of this study was to develop bismuth-based solid electrolytes with high ionic conductivity for intermediate temperature (500∼800oC) SOFC (solid oxide fuel cell) instead of conventional YSZ electrolytes showing very low ionic conductivity during 500∼800oC.
In this study, a series of Bi1-XNbxO1.5+δ powders were fabricated hydrothermally by altering the mineralizers, reaction temperature and holding time. The precursor of bismuth nitrate and niobium oxide were fabricated nano size Bi1-XNbXO1.5+δ powders.
The specimen were characterized by X-ray diffraction、scanning electron microscopy、 electrical conductivity. The morphology were spherical, can effectively control the powders morphology and mean powder size were 80~100 nm. Analysis of Bi3NbO7 cubic fluorite structure by XRD. Bi0.79Nb0.21O1.5+δ powders into dense pellets at sintered temperature 800oC/2 h, Bi0.79Nb0.21O1.5+δ had the highest conductivity by DC 4-wire resistance measurement. The conductivity was 0.35 Scm-1 at 800oC.

並列關鍵字

SOFC ； electrolyte ； hydrothermal ； Bi2O3

參考文獻

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