Structural Optimization Of The Passive Tubular Direct Methanol Fuel Cell And Performance Study On The Membrane Electrode Assembly

Direct Methanol Fuel Cell?DMFC?has a wide application prospect in mobile portable field.Considering the large size of traditional tablet DMFC and the high cost of bipolar plate,the researchers proposed the idea of Tubular DMFC?t-DMFC?.In this paper,a passive air-breathing t-DMFC fed with concentrated methanol was successfully developed.The structure of the t-DMFC was optimized,and the influence of stucture and operation parameters on the cell performance were investigated.Flexible membrane electrode assembly?MEA?was developed and effects of different process parameters were studied.The specific research contents can be summarized as follows:?1?Structure design of the t-DMFC and preparation of flexible MEAA fully passive air-breathing t-DMFC fed with concentrated methanol was designed and manufactured,which has a steel-tube anode and a steel-hood cathode.The flexible MEA was wraped around the anode tube which was prepared by GDE method and CCM method respectively.?2?Performance optimization and durability test of the flexible MEASeveral experiments have been carried out to explore the factors affecting the performance of MEA,such as Nafion content within catalytic layer,loading of catalyst,hot pressing and proton exchange membrane?PEM?.The self-developed MEA has a strong resistance to methanol crossover,and the maximum power density?MPD?under a methanol concentration of 8 M could reach 14.8 mW cm^-2.Galvanostatic method was used to test the durability of the flexible MEA.The experimental results showed that largeer discharge current density and excessively low or high concentration of methanol could reduce the durability of the MEA.?3?Structure and performance optimization of the t-DMFC.The operational and structural parameters affecting the performance of t-DMFC were studied,including the anode methanol concentration,the opening rate of cathode collector,the fastening pressure and the tube curvature.The MPD of the t-DMFC with a methanol concentration of 10 M could reach 13.15 mW cm^-2.The tube curvature has no significant impact on the cell performance.Forced air convection experiment showed that the the air-blowing operation reduced the cell temperature and this effect dominated the cell performance.In addition,the dynamic characteristics of t-DMFC were also inspected.