基于泡沫碳扩散层的直接甲醇燃料电池改性研究  

Study on direct methanol fuel cell performance modification based on foam carbon diffusion layer

作　　者：赵振刚[1,2] 周梦瑶 金典 张大骋 ZHAO Zhengang;ZHOU Mengyao;JIN Dian;ZHANG Dacheng(Faculty of Information Engineering and Automation,Kunming University of Science and Technology,Kunming 650500,Yunnan,China;Yunnan Key Laboratory of Green Energy,Electric Power Measurement Digitalization,Control and Protection,Kunming 650500,Yunnan,China)

机构地区：[1]昆明理工大学信息工程与自动化学院,云南昆明650500 [2]云南省绿色能源与数字电力量测及控保重点实验室,云南昆明650500

出　　处：《化工学报》2024年第S01期259-266,F0002,共9页CIESC Journal

基　　金：国家自然科学基金项目(62162035,62103174);云南省基础研究计划项目(202201AT070107,202401AT070391)。

摘　　要：扩散层(DL)是直接甲醇燃料电池(DMFC)膜电极组件(MEA)的重要结构,为反应物从流场到催化层的传质提供通道,随着反应的进行,扩散层也为电子从催化层到流场的传输提供通道,因此,扩散层的导电率和表面形貌影响燃料电池的整体性能。泡沫碳(foam carbon,FC)材料具有优异的导电性能和三维网状结构,将其作为阴极扩散层(CDL),能够降低燃料电池膜电极与集流板间的接触电阻、电荷转移电阻和传质电阻。同时,泡沫碳的较高孔隙率和较小的表面接触角,可增加DMFC阴极催化层暴露在空气中的比例,提供更多的气液两相流道,是较好的催化剂载体。研究结果表明,与传统碳纸比较,泡沫碳作为阴极扩散层的燃料电池峰值功率密度从24.47 mW/cm^(2)提升到39.24 mW/cm^(2),接触电阻由0.588Ω降低至0.494Ω,电荷转移电阻由2.784Ω降低至1.816Ω,传质阻抗由1.689Ω降低至1.417Ω。在100 mA/cm^(2)的电流放电条件下,FC的放电时长为60 min,碳纸作为DL的放电时长为46 min,FC作为扩散层有更长的放电时间。研究结果说明在相同甲醇浓度以及体积下,新型结构有着比常规结构更高的能量效率。Diffusion layer(DL)is an essential structure of a direct methanol fuel cell(DMFC)membrane electrode assembly(MEA),which provides a channel for the mass transfer of reactants from the flow field to the catalytic layer.As the reaction proceeds,the DL also provides a channel for the transport of electrons from the catalytic layer to the flow field.Therefore,the conductivity and surface morphology of the DL affects the overall performance of the fuel cell.The cathode diffusion layer(CDL)based on the foam carbon(FC)material could reduce the contact,charge transfer,and mass transfer resistance between the fuel cell membrane electrode and the current collector plate thanks to the FCs electrical conductivity and three-dimensional network structure.Moreover,the high porosity and small surface contact angle(CA)of FC could also increase the proportion of DMFC cathode catalytic layer exposed to the air and provide extra gas-liquid two-phase channels,which is the better catalyst support.Experimental results show that compared with the DMFC based on traditional carbon paper(CP-DMFC),the maximum power density of the DMFC with FC as the CDL(FC-DMFC)increases from 24.47 mW/cm^(2)to 39.24 mW/cm^(2),the contact resistance decreases from 0.588Ωto 0.494Ω,the charge transfer resistance decreases from 2.784Ωto 1.816Ω,and the mass transfer impedance decreased from 1.689Ωto 1.417Ω.Under a discharging current of 100 mA/cm^(2),the discharge time of FC-DMFC is 60 min,while the discharge time of CP-DMFC is 46 min,and FC as a diffusion layer has a longer discharge time.It shows that the new structure has higher energy efficiency under the same methanol concentration and volume than the conventional structure.

关 键 词：燃料电池 扩散层 泡沫碳 两相流 功率密度 

分 类 号：TM911.4[电气工程—电力电子与电力传动]