本文關鍵詞：鈣鈦礦基氧化物材料的制備及電化學性能研究　出處：《青島科技大學》2017年碩士論文　論文類型：學位論文

  更多相關文章： 固體氧化物燃料電池 鈣鈦礦型氧化物陰極材料 電解質骨架 電化學性能 氧還原反應

【摘要】：固體氧化物燃料電池(SOFC)可以將燃料中的化學能直接轉變?yōu)殡娔�。為了提高SOFC的電化學性能,尋找中低溫條件下具有優(yōu)越性能的陰極材料成為一個重要方向。鈣鈦礦基氧化物材料具有較高的電導率以及穩(wěn)定性,成為人們研究的熱點。本文以溶膠-凝膠法(sol-gel)制備了鈣鈦礦基氧化物陰極材料GdBaCo_2O_(5+δ)(GBCO)、SrFeO_(3-δ)(SFO)以及不同元素摻雜的氧化物材料,探討了其電化學性能,具體內容如下:本文合成了雙鈣鈦礦型氧化物陰極材料GdBaCo_2O_(5+δ)(GBCO)及Sr元素摻雜的GdBa0.7Sr0.3Co_2O_(5+δ)(GBSCO),并制備了Ce0.9Gd0.1O2(GDC)電解質材料;為進一步優(yōu)化電化學性能,構筑了GDC骨架/GDC電解質結構,并以質量比7:3的比例制備了GBSCO-GDC復合材料。將陰極材料在電解質上組裝成不同體系的半電池:GBCO/GDC、GBSCO/GDC、GBSCO-GDC/GDC和GBSCO/GDC骨架/GDC,并采用三電極法進行電化學性能測試。對制備的粉體、電解質片以及半電池利用熱重分析(TG)、X-射線衍射儀(XRD)和掃描電子顯微鏡(SEM)等進行性能表征。XRD結果表明,GBCO和GBSCO陰極粉體在950 ℃煅燒2 h后,具有良好的結晶性能,且GBSCO與GDC電解質材料在950 ℃煅燒1 h后沒有發(fā)生化學反應。相比致密的GDC電解質片,GDC骨架層呈現(xiàn)均勻多孔結構,粗糙度更高,GBSCO陰極材料與骨架層之間具有良好的連接性能,沒有出現(xiàn)大面積裂紋及孔洞。采用交流阻抗法和線性掃描法測試不同溫度下半電池的電化學性能。結果表明:Sr元素摻雜的GBSCO陰極材料電化學性能得到明顯改善,700 ℃時,GBSCO/GDC半電池的面積比界面電阻為0.547Ω·cm~2,明顯小于GBCO/GDC半電池;當測試電壓為0.8 V時,陰極電流密度達到0.209 A·cm-2;700 ℃時GBSCO/GDC、GBSCO-GDC/GDC和GBSCO/GDC骨架/GDC半電池的面積比界面電阻分別為0.547Ω·cm~2、0.166Ω·cm~2、0.118Ω·cm~2;測試電壓為0.8 V時,陰極電流密度分別為0.209 A·cm-2、0.458 A·cm-2、0.763 A·cm-2。復合陰極及電解質骨架的使用,有效改善了半電池的電化學性能,通過對比發(fā)現(xiàn),GBSCO陰極材料在GDC骨架表面受到的極化作用的影響最小,表現(xiàn)出最好的電化學性能。Co基雖然有著較高的導電率,但Co具有一定毒性,價格高,不利于SOFC商業(yè)化應用的發(fā)展。非Co基鈣鈦礦型氧化物由于具有較高的離子-電子導電性、良好的穩(wěn)定性以及合適的價格,成為一類值得關注的陰極材料。本文制備了SrFeO_3-δ(SFO)以及Cu、Mo元素摻雜的SrFe_(0.7)Cu_(0.2)Mo_(0.1)O_(3-δ)(SFCM)鈣鈦礦型陰極材料,研究燒結溫度對物相結構、微觀形貌和電化學性能的影響。XRD結果表明,800 ℃煅燒2 h的SFO和SFCM形成立方鈣鈦礦結構,且SFCM陰極與GDC電解質材料在800 ℃溫度下煅燒后,未發(fā)生化學反應,具有良好的高溫化學相容性。對SFO/GDC、SFCM/GDC、SFCM-GDC/GDC以及SFCM/GDC骨架/GDC半電池電化學性能進行測試。結果表明:750 ℃時,SFO/GDC半電池面積比界面電阻高達1.19Ω·cm~2,遠高于SFCM/GDC半電池(0.492Ω·cm~2)。700 ℃時,SFCM/GDC半電池的面積比界面電阻達到1.06Ω·cm~2,SFCM-GDC復合陰極以及GDC骨架層的使用使得面積比界面電阻分別降低了0.700Ω·cm~2和0.77Ω·cm~2;測試電壓為0.8 V時,SFCM陰極材料在GDC骨架/GDC電解質表面電流密度達到0.641 A·cm-2,表現(xiàn)出最優(yōu)異的電化學性能。以上結果表明:Cu、Mo元素摻雜的鈣鈦礦型氧化物明顯提高了陰極材料的電化學性能,復合陰極材料及電解質骨架層的使用可以有效提高半電池的電化學性能。在室溫條件下,將SFCM陰極粉體制備成薄膜工作電極,在0.1 mol/L的KOH堿性電解液中,采用三電極法利用旋轉環(huán)盤電極測試氧還原反應極化曲線以及循環(huán)伏安曲線,對其氧還原反應催化性能進行表征。測試結果表明,隨著SFCM工作電極轉速的增加,氧還原反應極限電流密度不斷增加,在2400 rpm時達到4.42mA/cm~2;在CV曲線中,正電位向負電位掃描的氧還原過程中出現(xiàn)較強的還原峰,SFCM陰極粉體具有較強的氧還原催化活性。
[Abstract]:Solid oxide fuel cell (SOFC) can be in the fuel chemical energy directly into electrical energy. In order to improve the electrochemical performance of SOFC cathode material has superior performance, find in low temperature condition has become an important direction. The electric conductivity and stability of perovskite oxide material has high, become the focus of the research in this paper. With sol gel (sol-gel) perovskite based oxide cathode materials were synthesized by using GdBaCo_2O_ (5+ 8) (GBCO), SrFeO_ (3- 8) (SFO) and different element doped oxide materials, discusses its electrochemical properties, the specific contents are as follows: double perovskite type oxide cathode material GdBaCo_2O_ was synthesized in this paper (5+ 8) (GBCO) and Sr doped GdBa0.7Sr0.3Co_2O_ (5+ 8) (GBSCO), and preparation of Ce0.9Gd0.1O2 (GDC) electrolyte materials; to further optimize the electrochemical performance, build a framework of GDC /GDC structure and electrolyte. GBSCO-GDC composite materials were prepared with the mass ratio of 7:3. The cathode material in the electrolyte assembled into different systems: GBCO/GDC, GBSCO/GDC, half cell GBSCO-GDC/GDC and GBSCO/GDC skeleton /GDC, and using three electrode method. The electrochemical performance of powder preparation, analysis of electrolyte and half battery use heat (TG), X- ray diffraction (XRD) and scanning electron microscopy (SEM) and characterization of.XRD showed that GBCO and GBSCO cathode powder calcined at 950 after 2 h, good crystallization performance, and the GBSCO and GDC electrolyte at 950 8C 1 h did not occur after the chemical reaction compared GDC electrolyte density, GDC skeleton layer exhibits a uniform porous structure, higher roughness, has the good performance of the connection between GBSCO cathode materials and the skeleton layer, no large area cracks and holes. The AC impedance and linear sweep The electrochemical properties of the half cell tracing test under different temperature. The results showed that the electrochemical performance of GBSCO cathode materials doped Sr were improved significantly, 700 degrees, GBSCO/GDC half cell area than the interface resistance of 0.547 cm~2, GBCO/GDC was significantly less than the half cell; when the test voltage is 0.8 V, the cathodic current density reached 0.209 A - cm-2; 700 degrees GBSCO/GDC, GBSCO-GDC/GDC and GBSCO/GDC framework /GDC half cell area were 0.547. Cm~2,0.166. Cm~2,0.118. Cm~2 is the interface resistance; the test voltage is 0.8 V, the cathodic current density was 0.209 A cm-2,0.458 A using cm-2,0.763 A cm-2. composite cathode and electrolyte skeleton effectively, improve the electrochemical performance of the half cell, by contrast, influence of GBSCO cathode material in the polarization of GDC by the surface of the frame is minimum, showed the best electrochemical.Co base is It has a high conductivity, but Co has a certain toxicity, the high price is not conducive to the development of SOFC commercial application. Co based perovskite oxides due to ion with high electronic conductivity, good stability and reasonable price, become a concern of the cathode material. The preparation of SrFeO_3- 8 this system (SFO) and Cu, Mo doped SrFe_ (0.7) Cu_ (0.2) Mo_ (0.1) O_ (3- 8) (SFCM) perovskite type cathode materials, the effects of sintering temperature on the phase structure, the effect of.XRD microstructure and electrochemical performance showed that 800 8C 2 h and SFO the formation of SFCM cubic perovskite structure, and SFCM cathode and GDC electrolyte material at 800 DEG C temperature after calcination, without chemical reaction, with high temperature chemical compatibility. For SFO/GDC, SFCM/GDC, SFCM-GDC/GDC and SFCM/GDC framework /GDC half cell electrochemical properties were tested. The results showed that: 750 degrees, SFO/GDC half cell area ratio of interface resistance as high as 1.19. Cm~2, far higher than the SFCM/GDC half cell (0.492. Cm~2).700 C, SFCM/GDC half cell area than the interface resistance reached 1.06. Cm~2, SFCM-GDC and GDC composite cathode skeleton layer makes the interface resistance area ratio were decreased 0.700. Cm~2 and 0.77. Cm~2; the test voltage is 0.8 V, the SFCM cathode material in the GDC skeleton of /GDC electrolyte surface current density reached 0.641 A - cm-2, exhibited excellent electrochemical performance. The above results show that: Cu, perovskite type oxide doped Mo significantly improves the electrochemical performance of cathode material the use of composite cathode material and electrolyte, the skeleton layer can effectively improve the electrochemical performance of the half cell. At room temperature, the SFCM cathode powder into thin film electrode in alkaline electrolyte, KOH 0.1 mol/L, the Using the rotating ring disk electrode test oxygen reduction reaction polarization curves and cyclic voltammetry curves of three electrode method, catalytic performance of oxygen reduction was investigated. The test results show that with the increase of SFCM speed of the working electrode, the oxygen reduction reaction limit current density increased, reaching 4.42mA/cm~2 at 2400 rpm; the CV curve, positive potential the reduction of negative potential scanning oxygen reduction peak appears for strong in the process of SFCM cathode powder has strong catalytic activity for oxygen reduction.

【學位授予單位】：青島科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB34;TM911.4

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本文編號：1427801