Sn掺杂CeO_(2)中Ce^(3+)的形成机制及其对质子交换膜燃料电池耐久性的影响  

Formation Mechanism of Ce^(3+)in Sn-Doped CeO_(2)and Its Effect on Durability of Proton Exchange Membrane Fuel Cells

作　　者：涂自强 何漩 杜星 陈辉 赵雷 张海军 王诚[2] TU Ziqiang;HE Xuan;DU Xing;CHEN Hui;ZHAO Lei;ZHANG Haijun;WANG Cheng(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science&Technology,Wuhan 430081,China;Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology,Tsinghua University,Beijing 100000,China)

机构地区：[1]武汉科技大学耐火材料与冶金省部共建国家重点实验室,武汉430081 [2]清华大学张家港氢能与先进锂电技术联合研究中心,北京100000

出　　处：《硅酸盐通报》2023年第5期1841-1851,共11页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(22105151,51802234)。

摘　　要：在质子交换膜燃料电池(PEMFC)运行过程中,产生的自由基会攻击质子交换膜,使其开裂或形成孔洞,导致电池失效。常见的改性方法是在质子交换膜(PEM)中添加自由基清除剂材料。基于此,本文合成了Sn掺杂CeO_(2)自由基清除剂,通过提高Ce^(3+)浓度来增强其在PEMFC中自由基清除性能,避免PEM厚度迅速减薄,从而提高质子PEMFC的耐久性。密度泛函理论计算和试验结果表明,Sn掺杂会引起CeO_(2)产生晶格畸变,降低氧空位形成能,促进CeO_(2)中Ce^(3+)的形成。同时,Sn^(2+)的加入可将CeO_(2)-Sn样品中的Ce^(4+)还原为Ce^(3+),提升Ce^(3+)的浓度,从而提高PEM的耐久性。单电池测试结果表明,经70 h的开路电压衰减测试,CeO_(2)-Sn-5%改性后的质子交换膜组装的单电池电压衰减率最低(18%),且功率保留率(56%)比其他样品更高,表明该样品具有更优异的耐久性。During the operation of a proton exchange membrane fuel cell(PEMFC),free radicals generated by PEMFC usually attack proton exchange membrane(PEM),causing the formation of crack or holes,which make the cell failure.Adding free radical scavenger material into PEM is regarded as a commonly modification method.Here,a Sn-doped CeO_(2)free radical scavenger was synthesized.By increasing the concentration of Ce^(3+),the free radical scavenging performance of CeO_(2)in PEMFC could be enhanced,which could avoid PEM thickness to decrease rapidly,and the durability of PEMFC could be improved.Density functional theory calculation and experimental results show that Sn-doping can cause lattice distortion of CeO_(2),reduce the formation energy of oxygen vacancy,and improve the formation of Ce^(3+)in CeO_(2).At the same time,the addition of Sn^(2+)can reduce Ce^(4+)in CeO_(2)-Sn to form Ce^(3+),which is conducive to increasing the concentration of Ce^(3+)and thus improving the durability of PEM.The results of single cell test show that the voltage attenuation rate of the single cell assembled with CeO_(2)-Sn-5%modified is the lowest(18%)and the power retention rate(56%)of the single cell is higher than that of other PEM after 70 h open circuit voltage decay test,which indicates that the sample has better durability.

关 键 词：CeO_(2) Sn掺杂 密度泛函理论计算 氧空位 质子交换膜燃料电池 耐久性 

分 类 号：TK91[动力工程及工程热物理]