本文選題：固體氧化物燃料電池 + 雙鈣鈦礦　； 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：固體氧化物燃料電池(SOFC)正朝著中低溫化的趨勢(shì)發(fā)展,而開(kāi)發(fā)性能優(yōu)異的中低溫電極材料和電解質(zhì)材料是其關(guān)鍵。Sr_2CoRO_6(R=Mo,Nb)雙鈣鈦礦材料是一種潛在的中低溫電極材料,本文對(duì)其電導(dǎo)率和導(dǎo)電機(jī)理進(jìn)行了研究。另外,La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(2.85)(LSGM)是非常有潛力的中溫區(qū)電解質(zhì)材料,但其性能在更低溫度下仍無(wú)法讓人滿意,因此本文采用兩相復(fù)合的手段對(duì)LSGM進(jìn)行了改性研究。采用固相法合成Sr_2CoRO_6雙鈣鈦礦材料,主要對(duì)其元素價(jià)態(tài)、晶體結(jié)構(gòu)和電導(dǎo)率進(jìn)行了分析,并建立了電子導(dǎo)電通道模型。XPS分析結(jié)果表明Sr_2CoMoO_6和Sr_2CoNbO_6中Co元素的主要價(jià)態(tài)分別為+2和+3。利用XRD研究Sr_2CoRO_6的晶體結(jié)構(gòu),并用Rietveld法計(jì)算其點(diǎn)陣參數(shù)用于構(gòu)建導(dǎo)電通道模型。采用四段子法測(cè)試Sr_2CoRO_6不同氧分壓下的電導(dǎo)率,結(jié)果表明,空氣中Sr_2CoMoO_6的電導(dǎo)率(0.36 S·cm~(-1),973 K)遠(yuǎn)低于Sr_2CoNbO_6(7.81 S·cm~(-1),973 K)。Sr_2CoMoO_6的電導(dǎo)率隨氧分壓降低而增大,在溫度為973 K,氧分壓為10~(-2)1 atm時(shí),達(dá)到2.05S·cm~(-1);Sr_2CoNbO_6則隨氧分壓降低而大幅減小。利用電子導(dǎo)電通道模型對(duì)Sr_2CoRO_6的導(dǎo)電特性進(jìn)行了闡釋。制備了(100-x)wt.%La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(2.85)-x wt.%Ce_(0.8)Gd_(0.2)O_(1.9)(x=0、5、10、20)電解質(zhì)材料,利用XRD對(duì)其物相進(jìn)行了研究,并采用Rietveld法計(jì)算其點(diǎn)陣參數(shù)。采用交流阻抗法對(duì)其阻抗進(jìn)行測(cè)試,結(jié)果表明:當(dāng)溫度在300~500℃時(shí),其晶內(nèi)電阻和晶界電阻均隨x的增大而增大;在650℃以后,總電阻隨x增大先減小后增大,x=5時(shí)取最小值。電池性能測(cè)試結(jié)果表明以95 wt.%La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(2.85)-5 wt.%Ce_(0.8)Gd_(0.2)O_(1.9)為電解質(zhì)的電池在800℃時(shí)具有最優(yōu)異的性能,最大電流密度為720 mA·cm~(-2),最高功率密度為192 mW·cm~(-2)。采用浸潤(rùn)法制備了La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(2.85)-(Li_(0.48)Na_(0.52))_2CO_3復(fù)合電解質(zhì),探討了不同含量PMMA造孔劑對(duì)其形貌及電導(dǎo)率的影響。結(jié)果表明:基體孔隙率隨PMMA含量增加而提高;復(fù)合電解質(zhì)的電導(dǎo)率隨PMMA含量的增加而增大,當(dāng)PMMA含量為40 wt.%時(shí),其電導(dǎo)率在600℃達(dá)到0.09 S·cm~(-1)。
[Abstract]:Solid oxide fuel cells (SOFCCs) are developing towards moderate and low temperature, and the development of excellent performance electrode materials and electrolyte materials is the key. Sr2CoRO6C / Nb) double perovskite is a potential medium and low temperature electrode material. In this paper, the conductivity and conduction mechanism are studied. In addition, LSGM is a potential electrolyte material in the medium temperature region, but its properties are still not satisfactory at lower temperature. Therefore, the modification of LSGM by two-phase composite method has been carried out in this paper. Sr_2CoRO_6 double perovskite materials were synthesized by solid state method. The elemental valence states, crystal structure and conductivity were analyzed. The electron conduction channel model was established. The results showed that the main valence states of Co in Sr_2CoMoO_6 and Sr_2CoNbO_6 were 2 and 3 respectively. The crystal structure of Sr_2CoRO_6 is studied by XRD, and the lattice parameters of Sr_2CoRO_6 are calculated by Rietveld method. The electrical conductivity of Sr_2CoRO_6 at different oxygen partial pressures was measured by four-stage method. The results showed that the conductivity of Sr_2CoMoO_6 in air was 0.36s / cm ~ (-1) ~ (-1) K), which was much lower than that of Sr_2CoNbO_6(7.81 S / C ~ (-1) K).Sr_2CoMoO_6 with the decrease of oxygen partial pressure. When the temperature was 973K and the oxygen partial pressure was 10-21 atm, the electrical conductivity of Sr_2CoMoO_6 in air increased with the decrease of oxygen partial pressure. Up to 2.05s cm-1, Sr2CoNbOS6 decreases significantly with the decrease of oxygen partial pressure. The conductive properties of Sr_2CoRO_6 are explained by using the electronic conduction channel model. The electrolytes of 100-xuwt.tig0.Ga0.Ga0.mg-0.2O / T ~ (2.85) -x ~ (WTT) have been prepared and their phase has been studied by means of XRD, and the lattice parameters have been calculated by means of Rietveld method. The electrolytes of this material have been studied by using the XRD method, and the structure of the electrolytes has been studied by means of the method of "XRD" and the method of "Rietveld" has been used to calculate the lattice parameters of the electrolytes. The impedance is measured by AC impedance method. The results show that both the intragranular resistance and grain boundary resistance increase with the increase of x when the temperature is 300 ~ 500 鈩，

本文編號(hào)：1969483