An Electrochemical Investigation of Methanol Crossover in Direct Methanol Fuel Cells

直接甲醇燃料电池（DMFC）具有能量密度高、安全、无污染等优点，是近年来新开发的一类燃料电池。甲醇来源丰富，价格便宜，易于存储，是便携式电子设备和电动汽车的理想动力源。然而，甲醇渗透造成电池性能衰退，是阻碍DMFC商业化的主要问题之一。因此，开展甲醇渗透的研究工作，建立适宜的表征方法，对阐明甲醇渗透和阻醇机理，推进DMFC的商业化进程有着重大的理论指导意义和实际应用价值。本论文工作的主要思路是通过考察不同条件下甲醇的电氧化行为，获得甲醇电氧化的动力学参数及影响因素，并利用甲醇电氧化来研究甲醇渗透行为和操作条件对甲醇渗透的影响。因此，采用循环伏安和计时电流测试技术考察了甲醇浓度、扫描速度、温度等...Direct methanol fuel cell (DMFC) has advantages of high power density, safety , low or zero emission and has been developed in recent years. Using methanol as a fuel，it is inexpensive, obtainable , convenient to carry and store. DMFC has become one of the most promising candidates as power sources in portable electronic products and electric vehicles. However, the degradation of cell performance d...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：20032510

Surface and Sructure Investigations of Membrane Electrode Assembly in DMFC Lifetime Testing~*

设计并组装单电池寿命测试系统,测试直接甲醇燃料电池(DMFC)的运行寿命,获得不同运行时间下单电池的极化和功率曲线.测试结束后,分别对运行过的膜电极(MEA)催化剂(铂黑和铂钌黑)和Nafion117(膜作XRD,HRTEM,FTIR及Raman等表征.考察在长期运行条件下电池寿命性能与膜电极中催化剂的颗粒大小、分布、形态、表面物种以及膜的结构之间的关系.寿命测试结果表明,单电池在不同运行阶段其性能变化也不同.运行前200 h,电池性能衰减较显著;运行200~704 h性能较稳定,运行1 002 h后电池性能恶化.波谱实验发现,单电池长期运行后,其膜电极的阴、阳极催化剂颗粒变大.电池寿命性能的衰退伴随膜电极微结构、表面组成、催化剂/膜界面结构的变化以及Nafion 117(膜的老化.The lifetime and performance of a direct methanol fuel cell (DMFC) were investigatedto understand the correlation between thestructure of catalysts /membrane and cell performanceversus time.The cell polarization and performance curves were obtained during the DMFC operation with the time.The catalysts and Nafion~ membrane of the membrane electrode assembly (MEA) from the lifetime test were comprehensively examined by XRD, HRTEM, FTIRand Raman spectroscope techniques.The results revealed that there was significant performance degradation during the first 200 hours operation; while the degradation was slowing down between 200 and 704hours operation.The degradation became worse after 1 002 h operation.The increases of the catalyst particle size from both anode and cathode catalysts wereobserved after the DMFC lifetime test.The changes of microstructure, surface composition, the interfacial structure of the MEA, and the aging of Nafion~ under the DMFC lifetime tests were also observed.作者联系地址：厦门大学化学系,厦门大学化学系,厦门大学化学系,厦门大学化学系,厦门大学化学系 固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005Author's Address: Department of Chemistry*, Department of Materials Science and Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005,Chin

DM FC中甲醇渗透的电化学研究(英文)

设计并建立甲醇渗透测试体系和模拟直接甲醇燃料电池(DMFC)运行体系,分别考察静态条件下H-cell中甲醇的渗透和运行条件下甲醇渗透对OCV的影响.循环伏安和计时电流法测试表明:随着渗透时间的延长,阴极侧的甲醇浓度增加;甲醇浓度增加,氧化峰电流增大,峰电位正移,氢在电极表面的吸脱附受到抑制,同时甲醇的正向氧化电流曲线出现肩峰.模拟DMFC实验测试结果表明:OCV先逐渐上升,接着发生突降,大约1.5 h后趋于稳定

DMFC寿命测试过程中膜电极的表面和结构研究(英文)

设计并组装单电池寿命测试系统,测试直接甲醇燃料电池(DMFC)的运行寿命,获得不同运行时间下单电池的极化和功率曲线.测试结束后,分别对运行过的膜电极(MEA)催化剂(铂黑和铂钌黑)和Nafion117(膜作XRD,HRTEM,FTIR及Raman等表征.考察在长期运行条件下电池寿命性能与膜电极中催化剂的颗粒大小、分布、形态、表面物种以及膜的结构之间的关系.寿命测试结果表明,单电池在不同运行阶段其性能变化也不同.运行前200 h,电池性能衰减较显著;运行200~704 h性能较稳定,运行1 002 h后电池性能恶化.波谱实验发现,单电池长期运行后,其膜电极的阴、阳极催化剂颗粒变大.电池寿命性能的衰退伴随膜电极微结构、表面组成、催化剂/膜界面结构的变化以及Nafion 117(膜的老化

An Electrochemical Investigation of Methanol Crossover in DMFCs

设计并建立甲醇渗透测试体系和模拟直接甲醇燃料电池(DMFC)运行体系,分别考察静态条件下H-cell中甲醇的渗透和运行条件下甲醇渗透对OCV的影响.循环伏安和计时电流法测试表明:随着渗透时间的延长,阴极侧的甲醇浓度增加;甲醇浓度增加,氧化峰电流增大,峰电位正移,氢在电极表面的吸脱附受到抑制,同时甲醇的正向氧化电流曲线出现肩峰.模拟DMFC实验测试结果表明:OCV先逐渐上升,接着发生突降,大约1.5 h后趋于稳定.Methanol crossover and its effect on the open-circuit voltage(OCV) in DMFCs were studied usingcyclic voltammetry and chronoamperometry under stationary condition and at ambient temperature.An H-shapecell was constructed and a simulative DMFC test was carried out to investigate methanol crossover through Na-fion(117 from anode to cathode.The results revealed thatthe amountof methanol in the cathode side is depend-ent upon the time of penetration.As the concentration of methanol increased,the hydrogen adsorption-desorptionon the surface of electrode was suppressed and a shoulder peak appeared during the forward sweep for methanoloxidation.The simulative DMFC test also showed that the methanol crossover caused a sudden decline in theOCV.作者联系地址：厦门大学化学系,厦门大学材料科学与工程系固体表面物理化学国家重点实验室,厦门大学化学系,厦门大学化学系 福建厦门361005Author's Address: 1.Department ofChemistry,2.Department ofMaterials Science and Engineering,State Key Laboratory for Physical Chemistry ofSolid Surfaces,Xiamen University,Xiamen361005,Fujian,Chin