本文關鍵詞： SOFC GDC 阻擋層 水系流延 燒結助劑　出處：《景德鎮(zhèn)陶瓷學院》2014年碩士論文　論文類型：學位論文

【摘要】：在過去20年里，固體氧化物燃料電池(Solid oxide fuel cell，SOFC）的研究取得了不菲的成果。傳統(tǒng)SOFC的工作溫度較高，會導致其電池壽命短和制造成本高等一系列問題，因此提高電極的催化性能、降低電池的工作溫度日趨成為研究重點�；旌想x子-電子導體LSCF比純電子導體LSM（傳統(tǒng)的陰極材料）對O2具有更高的催化活性，將其作為陰極的單電池在中低溫下?lián)碛懈叩姆烹娦阅�。但是LSCF與傳統(tǒng)電解質YSZ（Y2O3穩(wěn)定的ZrO2）發(fā)生反應生成的低電導相會影響電池性能，且與YSZ熱匹配性差，經(jīng)多次熱循環(huán)后易分層影響電池壽命。本課題主要圍繞制備與電極和電解質有良好的匹配性和化學相容性的GDC阻擋層而展開研究。 本文分別采用尿素和NH4HCO3作沉淀劑制備GDC（10mol%Gd2O3摻雜CeO2）納米粉體，通過對比這兩種粉體的形貌及其燒結體的燒結性能和電性能，得出NH4HCO3作沉淀劑合成的GDC更適合制備致密度高且氧離子導電性能好的阻擋層。通過對比分析陳化溫度、陳化時間、反應溫度、洗滌方式等對GDC粒徑和團聚性的影響，得出符合阻擋層要求的GDC粉體的制備工藝為：在60℃恒溫水浴鍋內，向已配好的0.1mol/L的Gd和Ce的硝酸鹽溶液中，邊攪拌邊按一定的速度逐滴加入NH4HCO3沉淀劑，直至溶液pH＞7。加料完全后的體系在80℃下陳化6小時，再將得到的乳白色沉淀，用去離子水和無水乙醇分別離心洗滌3次后置于70℃烘箱中烘干，最后在空氣氣氛下750℃煅燒保溫2h，獲得分散性良好且尺寸分布較均應的GDC粉體。 助燒結劑Bi2O3的添加，可有效地降低GDC的燒結溫度，，使之在1280℃時便可燒結致密，從而阻止了高溫共燒時GDC與YSZ間的反應。樣品相對密度隨著助燒結劑Bi2O3添加量的增加而增大，在3%的Bi2O3添加量下GDC的相對密度達最大值。GDC的電導率與其致密度變化一致，當含量為3%時電導率達最大值0.05388S/cm。這主要是由于樣品越致密越利于氧空位的遷移，電導率自然也就升高。 在相同條件下（700℃下，以3%H2O+H2為燃料，空氣為氧化氣體），添加GDC阻擋層的單電池的極化電阻和歐姆電阻分別為1.13Ωcm2和0.45Ωcm2，均遠小于未添加GDC層的單電池。這是因為阻擋層有效地避免了陰極和電解質之間的反應，阻止高阻抗物質Sr2ZrO4或La2Zr2O7的生成，使得電池性能得以提升。添加了阻擋層的單電池最大功率密度可達0.70W/cm2，而未添加GDC阻擋層的單電池最大功率密度僅為0.24W/cm2。
[Abstract]:In the past 20 years, solid oxide fuel cells (SOFCs) have achieved remarkable results. The high working temperature of traditional SOFC leads to a series of problems, such as short battery life and high manufacturing cost, so the catalytic performance of the electrodes is improved. Reducing the working temperature of the battery is becoming the focus of the research. The mixed ion-electronic conductor LSCF has higher catalytic activity to O2 than the pure electronic conductor LSM (traditional cathode material). However, the low conductance phase formed by the reaction of LSCF with the traditional electrolyte YSZ(Y2O3 stabilized ZrO2 will affect the performance of the cell, and its thermal compatibility with YSZ is poor. It is easy to delaminate the battery life after repeated thermal cycles. This paper focuses on the preparation of GDC barrier layer with good matching and chemical compatibility with electrodes and electrolytes. In this paper, urea and NH4HCO3 were used as precipitators to prepare GDC(10mol%Gd2O3 doped CEO _ 2 nano-powders. The morphology, sintering properties and electrical properties of the two kinds of powders were compared. It is concluded that GDC synthesized with NH4HCO3 as precipitant is more suitable for the preparation of barrier layers with high density and good oxygen ion conductivity. The effects of aging temperature, aging time, reaction temperature and washing method on the particle size and agglomeration of GDC are compared and analyzed. The preparation process of GDC powder which meets the requirements of barrier layer is obtained as follows: in 60 鈩

本文編號：1521239