本文選題：固體氧化物燃料電池 + 雙鈣鈦礦��； 參考：《吉林大學(xué)》2016年博士論文

【摘要】：固體氧化物燃料電池(SOFC)是一種能量轉(zhuǎn)換效率高、環(huán)境污染少的新型能源技術(shù)。近年來(lái),工作溫度在600-800°C的中溫固體氧化物燃料電池(IT-SOFC)逐漸受到人們的關(guān)注。相對(duì)于傳統(tǒng)SOFC,更低的工作溫度,使得IT-SOFC在電池材料的選擇范圍、電池工作的穩(wěn)定性以及電池制造成本等方面具有明顯的優(yōu)勢(shì)。由于傳統(tǒng)的SOFC陰極材料不適宜在中溫范圍(600-800°C)內(nèi)工作,因此開(kāi)發(fā)新型IT-SOFC陰極材料對(duì)于促進(jìn)SOFC技術(shù)的發(fā)展,具有非常重要的意義。本文以備受關(guān)注的AA'B_2O_(5+δ)雙鈣鈦礦陰極材料LnBa Co_2O_(5+δ)(Ln BCO)為基礎(chǔ),通過(guò)不同的摻雜策略,對(duì)其電導(dǎo)率、熱膨脹以及電化學(xué)催化性能進(jìn)行優(yōu)化,以期開(kāi)發(fā)出性能更加優(yōu)異的IT-SOFC陰極材料。我們用固相法合成了A位Ca~(2+)摻雜的Pr_(1-x)Ca_xBa Co_2O_(5+δ)(x=0.10-0.40;PCBCO)陰極材料。發(fā)現(xiàn)PCBCO(x=0.10,0.20)樣品形成了單相的四方結(jié)構(gòu)雙鈣鈦礦氧化物;而PCBCO(x=0.30,0.40)樣品則有不同程度的雜質(zhì)出現(xiàn)。PCBCO陰極與SDC電解質(zhì)在950°C煅燒10 h的條件下呈現(xiàn)出良好的化學(xué)兼容性。在Ca~(2+)部分替代Pr~(3+)的PCBCO樣品中,由于Pr~(3+)位離子平均氧化態(tài)降低,導(dǎo)致樣品氧含量隨Ca的摻雜而降低。隨著Ca摻雜量的增加,樣品中更多的Co~(3+)被穩(wěn)定在中自旋態(tài),致使PCBCO樣品的熱膨脹系數(shù)(TEC)呈下降趨勢(shì)。在100-800°C溫度范圍內(nèi)x=0.10-0.30樣品的平均TEC值分別為22.2×10~(-6)、20.0×10~(-6)和19.1×10~(-6) K~(-1),均小于未摻雜的Pr BCO陰極材料在同樣溫度范圍內(nèi)的TEC。在PCBCO中引入SDC電解質(zhì)材料可以進(jìn)一步降低材料的TEC。PCBCO(x=0.10)-SDCy(y=40 wt.%)復(fù)合陰極在100-800°C溫度范圍內(nèi)的平均TEC值下降到17.4×10~(-6) K~(-1)。PCBCO(x=0.10-0.30)樣品在300-850°C溫度范圍內(nèi)具有金屬性導(dǎo)電行為,電導(dǎo)率大于300 S cm~(-1),比Pr BCO的電導(dǎo)率有所降低。這歸因于PCBCO中較低的氧含量導(dǎo)致載流子(Co~(4+))濃度降低。PCBCO(x=0.10)-SDC復(fù)合陰極的電導(dǎo)率隨SDC含量增加逐漸下降,但在300-850°C溫度范圍內(nèi)電導(dǎo)率仍然大于100 S cm~(-1)。PCBCO(x=0.10-0.30)樣品的ASR隨Ca摻雜量的增加而增大,700°C時(shí)PCBCO陰極在SDC電解質(zhì)上的ASR分別為0.081、0.082和0.089Ωcm~2,高于Pr BCO陰極材料的ASR值。導(dǎo)致PCBCO(x=0.10-0.30)陰極ASR增大的主要原因是:Ca的摻雜在樣品中引入了過(guò)量的氧空位,導(dǎo)致缺陷聚集,氧離子傳導(dǎo)性能下降。SDC的引入有助于改善陰極材料的電化學(xué)性能,最佳比例的PCBCO(x=0.10-0.30)-SDCy(y=20 wt.%)復(fù)合陰極在700°C時(shí)的ASR值分別為0.060、0.071和0.074Ωcm~2。單電池輸出性能研究表明,800°C時(shí),以PCBCO(x=0.10-0.30)為陰極的單電池,最大功率密度分別為646.5、636.8和620.6 m W cm~(-2);以PCBCO(x=0.10-0.30)-SDCy(y=20 wt.%)復(fù)合材料為陰極的單電池輸出性能進(jìn)一步改善,800°C時(shí)最大功率密度分別達(dá)到了684.7、660.2和644.3 m W cm~(-2)。上述研究結(jié)果表明,Ca~(2+)在A位摻雜可降低PCBCO材料的熱膨脹系數(shù),同時(shí)也降低了稀土材料的成本;PCBCO(x=0.10-0.30)陰極和PCBCO(x=0.10-0.30)-SDCy(y=20 wt.%)復(fù)合陰極均表現(xiàn)出良好的電化學(xué)性能,是很有發(fā)展前途的潛在IT-SOFC陰極材料。A位Ca~(2+)摻雜的PCBCO陰極材料在熱膨脹性能方面得到了一定程度的改善,但電化學(xué)性能卻隨著Ca的引入而有所下降。為了提高Pr BCO的電化學(xué)性能,我們用固相法合成了A'位Ca摻雜的PrBa_(1-x)Ca_xCo_2O_(5+δ)(x=0.05-0.15,PBCCO)陰極材料。發(fā)現(xiàn)PBCCO樣品為具有四方結(jié)構(gòu)的雙鈣鈦礦型氧化物,與SDC電解質(zhì)在950°C煅燒10 h的條件下具有良好的化學(xué)兼容性。隨著Ca的摻雜,具有自旋態(tài)轉(zhuǎn)變特性的Co~(3+)離子所占比例減少,使得PBCCO樣品從x=0.05到0.15,TEC呈下降趨勢(shì),在100-800°C溫度范圍內(nèi),樣品的平均TEC值分別為22.6×10~(-6)、21.6×10~(-6)和20.9×10~(-6) K~(-1),相比于未摻雜的Pr BCO,TEC有所下降。在300-850°C溫度范圍內(nèi),PBCCO樣品具有金屬性導(dǎo)電行為,電導(dǎo)率大于620 S cm~(-1)。從x=0.05到0.15,PBCCO樣品中載流子(Co~(4+))濃度逐漸升高,使得電導(dǎo)率呈上升趨勢(shì)。隨著Ca的摻雜,PBCCO樣品中氧空位逐漸減少,氧離子傳導(dǎo)性能下降,導(dǎo)致PBCCO陰極材料在SDC電解質(zhì)上的ASR呈上升趨勢(shì),700°C時(shí)PBCCO陰極在SDC電解質(zhì)上的ASR值分別為0.047、0.050和0.052Ωcm~2。相比于未摻雜的Pr BCO,PBCCO的ASR明顯降低,這得益于PBCCO系列樣品較高的電導(dǎo)率和較低的TEC。單電池輸出性能測(cè)試表明,800°C時(shí),以PBCCO(x=0.05-0.15)為陰極的單電池,最大功率密度分別為669.7、634.1和577.4 m W cm~(-2)。上述研究結(jié)果表明,Ca~(2+)離子在A'位置摻雜,可降低PBCCO材料的熱膨脹系數(shù),提高電學(xué)和電化學(xué)性能;PBCCO(x=0.05-0.15)陰極材料具有優(yōu)秀的電化學(xué)催化性能,是很有應(yīng)用前景的IT-SOFC陰極材料。Ln BCO基陰極材料由于其所含的Co~(3+)離子隨著溫度的升高會(huì)出現(xiàn)由低自旋態(tài)向高自旋態(tài)的轉(zhuǎn)變,導(dǎo)致材料具有很高的TEC。通過(guò)前面提到的不同摻雜策略可使其熱膨脹性能獲得一定改善,但仍然無(wú)法達(dá)到與電解質(zhì)材料十分匹配的熱膨脹系數(shù)。為此,我們合成了不含Co元素的Sm Ba Fe Ni O5+δ(SBFN)雙鈣鈦礦陰極材料。研究發(fā)現(xiàn),SBFN為具有四方結(jié)構(gòu)的雙鈣鈦礦氧化物,與SDC電解質(zhì)在950°C煅燒10 h的條件下化學(xué)兼容性良好。SBFN樣品在30-900°C溫度范圍內(nèi)的平均TEC為14.1×10~(-6) K~(-1),遠(yuǎn)低于含Co的Sm BCO材料。SBFN較低的TEC緣于以Fe和Ni完全取代了Co元素,材料的熱膨脹性能不再受Co~(3+)離子自旋態(tài)轉(zhuǎn)變的影響。此外,Fe-O鍵的結(jié)合能比Co-O鍵的結(jié)合能更高,也有助于減弱晶格膨脹,因此降低了TEC。在SBFN中引入SDC電解質(zhì)材料所構(gòu)成的復(fù)合陰極,其熱膨脹匹配性得到了進(jìn)一步改善。SBFN-SDCx(x=5,10,15 wt.%)復(fù)合陰極的TEC分別為13.8×10~(-6)、13.4×10~(-6)和12.0×10~(-6) K~(-1)。電導(dǎo)率研究表明,SBFN樣品在300-425°C溫度范圍內(nèi)呈半導(dǎo)體導(dǎo)電特性;而在425-850°C溫度范圍內(nèi)呈金屬導(dǎo)電特性,在425°C時(shí)具有最大電導(dǎo)率,為48 S cm~(-1)。700°C時(shí),SBFN在SDC電解質(zhì)上的ASR值為0.386Ωcm~2。在SBFN中引入SDC電解質(zhì)可以提高陰極的電化學(xué)性能,700°C時(shí)SBFN-SDC10陰極的ASR值為0.224Ωcm~2,相對(duì)于單相的SBFN陰極,極化阻抗降低了42%。800°C時(shí),以SBFN和SBFN-SDC10為陰極的單電池,最大功率密度分別為367.6 m W cm~(-2)和507.8m W cm~(-2)。以上研究結(jié)果表明,用Fe和Ni完全置換Co,可明顯地降低無(wú)鈷陰極材料SBFN的熱膨脹系數(shù);經(jīng)過(guò)性能優(yōu)化,SBFN-SDC10復(fù)合陰極材料表現(xiàn)出較好的陰極性能,可作為IT-SOFC的候選陰極材料。我們采用三種不同的摻雜策略,研究了降低Co基雙鈣鈦礦陰極材料Ln BCO熱膨脹系數(shù)的方法,為探尋Ln BCO雙鈣鈦礦陰極材料的改性與優(yōu)化提供了有益的參考和借鑒。
[Abstract]:Solid oxide fuel cell (SOFC) is a new energy technology with high energy conversion efficiency and less environmental pollution. In recent years, the medium temperature solid oxide fuel cell (IT-SOFC) at the working temperature of 600-800 C has been gradually paid attention to. Compared with the traditional SOFC, the lower working temperature makes IT-SOFC in the selection range of the battery material. The stability of the pool work and the cost of battery manufacturing have obvious advantages. Since the traditional SOFC cathode materials are not suitable for the medium temperature range (600-800 C), it is very important to develop a new type of IT-SOFC cathode material for the development of SOFC technology. This paper is a highly concerned AA'B_2O_ (5+ delta) double calcium titanium. Based on the cathode material LnBa Co_2O_ (5+ delta) (Ln BCO), the conductivity, thermal expansion and electrochemical catalytic properties of the cathode materials were optimized by different doping strategies, in order to develop a IT-SOFC cathode material with better performance. We synthesized A bit Ca~ (2+) doped Pr_ (1-x) Ca_xBa cathode (A) cathode by solid phase method. Material. It was found that PCBCO (x=0.10,0.20) samples formed a single phase tetragonal perovskite oxide, while PCBCO (x=0.30,0.40) samples showed a good chemical compatibility with.PCBCO cathode and SDC electrolyte at 950 degree C calcined 10 h. The average oxidation state of the + + ions is reduced and the oxygen content of the sample decreases with the doping of Ca. With the increase of Ca doping, more Co~ (3+) in the sample is stabilized in the middle spin state, resulting in the decrease of the thermal expansion coefficient (TEC) of the PCBCO samples. The average TEC value of x=0.10-0.30 samples in the range of 100-800 degree C is 22.2 x 10~ (-6), 20, respectively. X 10~ (-6) and 19.1 x 10~ (-6) K~ (-1) are less than the undoped Pr BCO cathode materials in the same temperature range, and the introduction of SDC electrolyte in PCBCO can further reduce the average value of the material in the range of 100-800 degree temperature. 0.30) in the range of 300-850 C temperature, the sample has metallic conduction behavior, the conductivity is greater than 300 S cm~ (-1), and the conductivity of Pr BCO is lower than that of Pr BCO. This is attributed to the lower oxygen content in PCBCO which leads to the decrease of the carrier (Co~ (4+)) concentration of.PCBCO (x=0.10) and the conductivity of the -SDC compound cathode gradually decreases with the increase of the content, but at 300-850 degree temperature. The range of electrical conductivity is still greater than 100 S cm~ (-1).PCBCO (x=0.10-0.30).PCBCO (x=0.10-0.30) sample increases with the increase of Ca doping. The ASR of PCBCO cathode on SDC electrolyte at 700 degree C is respectively 0.081,0.082 and 0.089 Omega, which is higher than that of the cathode material. The introduction of excessive oxygen vacancies leads to defects aggregation, and the introduction of oxygen ion conductivity decrease.SDC is helpful to improve the electrochemical performance of cathode materials. The optimum proportion of the PCBCO (x=0.10-0.30) -SDCy (y=20 wt.%) composite cathode at 700 degree C is respectively 0.060,0.071 and 0.074 Omega cm~2. single battery output performance studies show that the 800 degree C, The maximum power density of the single cell with PCBCO (x=0.10-0.30) as the cathode is 646.5636.8 and 620.6 m W cm~ (-2), and the output performance of the single cell with PCBCO (x=0.10-0.30) -SDCy (y=20 wt.%) composite as the cathode is further improved. The maximum power density at 800 degrees is reached and 644.3 respectively. The above results show that The doping of Ca~ (2+) in A can reduce the thermal expansion coefficient of the PCBCO material and reduce the cost of the rare earth materials. The PCBCO (x=0.10-0.30) cathode and the PCBCO (x=0.10-0.30) -SDCy (y=20 wt.%) composite cathode both show good electrochemical performance, and are promising cathode materials of potential IT-SOFC cathode materials in the future. The properties of thermal expansion were improved to a certain extent, but the electrochemical performance decreased with the introduction of Ca. In order to improve the electrochemical performance of Pr BCO, we synthesized A'Ca doped PrBa_ (1-x) Ca_xCo_2O_ (5+ delta) (5+ delta) (x=0.05-0.15, PBCCO) cathode material by solid phase method. It was found that the PBCCO samples were double perovskite with the Quartet structure. The type oxides have good chemical compatibility with the SDC electrolyte at 950 C calcined at 10 h. With the doping of Ca, the proportion of Co~ (3+) ions with the spin state transformation decreases, making the PBCCO samples from x=0.05 to 0.15 and TEC decreasing. The average TEC value of the sample is 22.6 * 10~ (22.6), 21., respectively, within the range of 100-800 degree C. 6 * 10~ (-6) and 20.9 x 10~ (-6) K~ (-1), compared to the undoped Pr BCO, the TEC decreased. In the temperature range of 300-850 degree C, the PBCCO sample has a metallic conduction behavior, and the conductivity is greater than 620 S. The oxygen vacancy in the sample decreases gradually and the conductivity of oxygen ion decreases. The ASR of the PBCCO cathode material on the SDC electrolyte increases. The ASR value of the PBCCO cathode on the SDC electrolyte is 0.047,0.050 and 0.052 Omega cm~2. at 700 degree C, respectively, compared to the BCO Pr BCO, which is due to the higher electricity of the series of samples. The conductivity and low TEC. single cell output performance test showed that the maximum power density of the single cell with PBCCO (x=0.05-0.15) as the cathode at 800 C was 669.7634.1 and 577.4 m W cm~ (-2) respectively. The results showed that the doping of Ca~ (2+) ions in the A'position could reduce the thermal expansion coefficient of the material and improve the electrical and electrochemical properties. (x=0.05-0.15) the cathode material has excellent electrochemical catalytic performance. It is a promising cathode material for IT-SOFC cathode material.Ln BCO based cathode material, because of its Co~ (3+) ions as the temperature increases with the temperature, the transition from low spin to high spin will result in the material with a very high TEC. through the different doping strategies mentioned earlier. It can improve the thermal expansion performance, but still can not reach the thermal expansion coefficient that matches the electrolyte material. Therefore, we synthesized the Sm Ba Fe Ni O5+ Delta (SBFN) Double Perovskite Cathode material without Co elements. It was found that SBFN was a tetragonal perovskite oxide with a quartet structure, and the SDC electrolyte was calcined at 950 degree C in 10 h. Under the conditions of good chemical compatibility, the average TEC of.SBFN samples in the temperature range of 30-900 C is 14.1 x 10~ (-6) K~ (-1), which is far lower than the Sm BCO containing Co. The TEC is due to the replacement of the element, and the thermal expansion of the material is no longer influenced by the spin state transformation of the ions. The bonding energy of the bond is higher and helps to weaken the lattice expansion, thus reducing the TEC. composite cathode made by the introduction of the SDC electrolyte in SBFN. The thermal expansion matching has been further improved by the TEC of the.SBFN-SDCx (x=5,10,15 wt.%) composite cathode, 13.8 x 10~ (-6), 13.4 x 10~ (-6) and 12 * 10~. It is clear that the SBFN sample has the conductivity of semiconductor in the temperature range of 300-425 C; the conductivity of the metal is in the range of 425-850 degree C, and the maximum conductivity at 425 C. When it is 48 S cm~ (-1).700 [C], the ASR value of SBFN on the SDC electrolyte is 0.386 Omega, which can improve the electrochemical performance of the cathode, 700 degrees. The ASR value of the SBFN-SDC10 cathode is 0.224 Omega cm~2. Relative to the single phase SBFN cathode, the polarization impedance reduces the 42%.800 degree C, the single battery with SBFN and SBFN-SDC10 as the cathode, the maximum power density is 367.6 m W cm~, respectively. The thermal expansion coefficient of SBFN has been optimized. The SBFN-SDC10 composite cathode material shows good cathodic properties and can be used as the candidate cathode material for IT-SOFC. We have studied the method of reducing the Ln BCO thermal expansion coefficient of the Co Based Double Perovskite Cathode material by three different doping strategies, in order to explore the modification of the Ln BCO Double Perovskite Cathode material. It provides useful reference and reference for nature and optimization.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TM911.4

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