一体化BaZrO3基电解质基体结构低温质子陶瓷膜燃料电池的设计、制备与性能研究

Protonic ceramic membrane fuel cell (PCMFC) has attracted much attention due to its high efficiency of electricity generation and capability of low temperature operation. Perovskite-type BaZrO3 based proton conductor especially BaZr0.8Y0.2O3-δ (BZY) shows good chemical stability and high bulk conductivity. But due to its poor sinterability, the total proton conductivity of BZY ceramics is rather low. Enlarging the grain size of BZY allows it achieve high total proton conductivity at low temperature, but it need to elevate the sintering temperature. However, too high sintering temperature will not benefit to the fabrication of high performance anode-supported PCMFC. In this project, suitable co-doping BZY based electrolyte materials are selected, and PCMFC with integrated electrolyte substrate is designed, and tape-casting combining with in-situ reaction technique can be applied to fabricate such substrate, which have no need to synthesize electrolyte powder, and avoid the high temperature cofiring with porous anode substrate, thus impregnating process can be used to load nano catalysts at low temperature, and high cell output is expected. We will mainly study the property and the rule of charge transfer in integrated cell, and explore the affecting role of cell electrochemical performance by cell fabrication technolgy, realize the low cost and cotrollable large scale fabrication, and promote its commercilization application.

质子陶瓷膜燃料电池(PCMFC)以其发电效率高、操作温度低的优势受到人们的广泛关注。钙钛矿型BaZrO3基质子导体如BaZr0.8Y0.2O3-δ (BZY)化学稳定性好，体电导率高，是PCMFC的最佳候选电解质材料。但由于BZY的烧结活性差，总的质子电导率很低。增大BZY的晶粒尺寸可以在低温下获得高的总质子电导率，但需要提高烧结温度。然而，过高的烧结温度不利于制备高性能阳极支撑的PCMFC。本课题选择采用合适的共掺杂BZY基电解质材料，设计一体化电解质基体结构PCMFC，采用流延结合原位反应技术制备基体结构，无需合成电解质粉体，同时避免了与多孔阳极基体高温共烧，有利于采用浸渍工艺在基体中低温负载纳米催化剂，有望获得高的电池输出。主要研究一体化电池中电荷输运的性质和规律，探索电池制备工艺对一体化电池的电化学性能和稳定性的影响规律，实现一体化电池的低成本、可控规模化制备，促进其商业化应用。

基于钙钛矿氧化物质子导体薄膜电解质的质子陶瓷膜燃料电池（PCMFC）适合在400-700oC的中低温范围内操作，输出性能良好、能直接利用碳氢燃料，且耐硫、抗积碳、耐久性高，具有很大的应用潜力，成为传统氧离子传导固体氧化物燃料电池的最佳替代。在目前开发的钙钛矿氧化物质子导体中，BaZrO3基氧化物如BaZr0.8Y0.2O3-δ（BZY）具有高的化学稳定性和体电导率，但成相温度高、烧结性能差、总质子电导率偏低。要获得高的质子电导率，通常需要在高达1600oC以上烧结，这给高性能阳极支撑结构的PCMFC的制备带来困难。本项目针对BZY电解质材料的特性，提出了多孔/致密双层或多孔/致密/多孔三层一体化电解质基体电池结构设计，便于电解质高温烧结，同时有利于采用浸渍工艺在基体中低温负载纳米催化剂改善电极催化活性，并发展新型流延结合原位固相反应烧结技术成功制备了单电池。研究发现，对于成相粉体的和反应烧结的BZY电解质材料，其在600oC下的质子电导率均达到10-3 S·cm-1量级；基于合成的BZY粉体干压制备的多孔/致密双层BZY电解质基体单电池，当NiO浸渍量为30wt.%时，在600oC下最大输出功率密度达到112mW·cm-2；采用流延-叠压-固相反应烧结制备的单电池在600oC下最大输出功率密度达到170mW·cm-2，在0.7V操作电压下以155mA·cm-2的电流密度稳定放电20h；而采用双层共流延结合固相反应烧结制备的单电池，当多孔电解质层中石墨的添加量为40g/165g原料粉体时，在600oC下最大输出功率密度达到134mW·cm-2；通过优化工艺参数实现了一体化BZY电解质基体PCMFC的低成本、结构可控制备，将促进其商业化应用。