本文選題：固體氧化物燃料電池　切入點：NiO/YSZ陽極　出處：《山東大學(xué)》2017年碩士論文

【摘要】：固體氧化物燃料電池(Solid oxide fuel cell,SOFC)是新型綠色發(fā)電技術(shù),采用離子導(dǎo)體為隔膜,直接將化學(xué)能轉(zhuǎn)化為電能,能量轉(zhuǎn)換效率高,安全環(huán)保,很有發(fā)展前景。然而其工作溫度較高會引發(fā)諸多問題,降低SOFC的使用壽命和工作效率,實現(xiàn)電池中低溫化的常用方法就是采用陽極支撐SOFC,將電解質(zhì)材料制備成薄膜。作為SOFC的重要組成部分,陽極支撐體與電解質(zhì)薄膜的性能極為重要。首先以石墨為造孔劑制備多孔NiO/YSZ陽極材料,探討造孔劑含量對陽極材料微觀結(jié)構(gòu)及各項性能的影響。結(jié)果表明隨著造孔劑含量的增加,陽極材料的開氣孔率和收縮率等逐漸增加,抗熱震性能得到改善,而其彎曲強度和電導(dǎo)率有所降低。其中石墨含量1Owt%的陽極材料,彎曲強度在50MPa左右,還原后氣孔率達到38%,電導(dǎo)率為720s/cm,滿足SOFC正常工作的基本要求。其次通過干壓成型法制備出梯度陽極材料,使陽極從支撐層到功能層NiO和造孔劑含量遞減,原料粉體顆粒逐漸細化,孔隙率降低,從而增加陽極的催化活性,使陽極材料工作壽命延長,性能提高。對于陽極功能層,原料球磨時間越長,則粉體顆粒越細,混合越均勻,從而保證了較高的反應(yīng)三相界面。然后采用漿料旋涂法在陽極支撐體上制備電解質(zhì)薄膜,研究各項旋涂工藝參數(shù)對電解質(zhì)薄膜厚度和致密性的影響。發(fā)現(xiàn)粘結(jié)劑中乙基纖維素含量為3wt%,固相含量為40wt%,陽極預(yù)燒溫度為800℃時,薄膜致密性較好。旋涂時間為20s,轉(zhuǎn)速4000r/min,旋涂4次時,可以得到厚度15um左右的電解質(zhì)薄膜。薄膜厚度均勻平整,與陽極支撐體連接緊密。在YSZ漿料中加入Bi203作為燒結(jié)助劑,不僅可以降低燒結(jié)溫度,提高致密性,還能促進晶粒生長,降低電解質(zhì)材料的晶界電阻。但過多的Bi2O3會導(dǎo)致部分c-ZrO2轉(zhuǎn)變?yōu)檠蹼x子電導(dǎo)率較低的m-ZrO2,同時降低了電解質(zhì)的抗熱震性能。添加3wt%Bi2O3的YSZ電解質(zhì)在125℃時的相對密度為97.5%,達到純YSZ電解質(zhì)在1450℃燒結(jié)后的致密性,避免了 m-ZrO2的生成,較為合適。最后采用溶膠凝膠法制備出比表面積較大、反應(yīng)活性較高的鈣鈦礦型LSM陰極粉體。將LSM與YSZ混合,球磨時間越長,粉體混合越均勻,顆粒越細小。通過旋涂法在陽極支撐電解質(zhì)上制備復(fù)合陰極薄膜,可得到SOFC單電池。漿料中乙基纖維素起到粘結(jié)劑和造孔劑的雙重作用,其含量為6wt%的復(fù)合陰極在110℃燒結(jié)后骨架結(jié)構(gòu)細化,孔隙細小均勻,薄膜表面平整,且與電解質(zhì)接觸緊密,使陰極擁有更多的三相界面,電化學(xué)活性提高。
[Abstract]:Solid oxide fuel cell (SOFC) is a new type of green power generation technology, which uses ionic conductor as the diaphragm, converts chemical energy directly into electric energy, has high energy conversion efficiency, and is safe and environmentally friendly. It has a bright future. However, its high working temperature will lead to many problems and reduce the service life and efficiency of SOFC. The common way to realize low temperature in battery is to use anode to support SOFCs, and make electrolyte materials into thin films, which is an important part of SOFC. The properties of anodic support and electrolyte film are very important. Firstly, porous NiO/YSZ anode materials are prepared by using graphite as pore-forming agent. The effect of the content of pore-making agent on the microstructure and properties of anode materials is discussed. The results show that the opening porosity and shrinkage rate of anode materials increase gradually with the increase of pore-making agent content, and the thermal shock resistance of anode materials is improved. The bending strength and electrical conductivity of the anode material with graphite content of 1 Owt% decreased, and the bending strength of the anode material was about 50MPa. After reduction, the porosity is 38 and the conductivity is 720s / cm, which meets the basic requirements of SOFC normal operation. Secondly, gradient anode materials are prepared by dry compression molding, and the content of NiO and pore-forming agent decreases from the supporting layer to the functional layer. The particle size of the raw material gradually refines and the porosity decreases, thus increasing the catalytic activity of the anode, prolonging the working life and improving the performance of the anode material. For the anode functional layer, the longer the milling time of the raw material is, the finer the powder particle is, and the more uniform the mixing is, Thus a high reactive three-phase interface is ensured. Then the electrolyte film is prepared on the anode support by slurry spin coating method. The effects of various spin-coating process parameters on the thickness and densification of electrolyte film were studied. It was found that when the content of ethyl cellulose in binder was 3 wt, the solid content was 40 wtand the anodic prefiring temperature was 800 鈩，

本文編號：1700431