针对空气自呼吸式直接甲醇燃料电池甲醇易渗透和阴极易水淹的特点,通过对催化层催化剂载量、阴极微孔层、阳极微孔层和膜等因素进行调控,对膜电极结构和性能的进行了优化.结果表明,使用高载量催化剂能有效降低甲醇渗透,但载量过高会引起传质阻力.当阳极微孔层PTFE含量为30%(bymass)时,可以有效促进CO2的均一析出,从而降低甲醇浓度梯度,减小甲醇透过.综合考虑甲醇渗透和阴极自返水,经优化后所得MEA在室温时自呼吸工作条件下,比功率密度达到33mW·cm-2,最优甲醇工作浓度为4mol·L-1.
马亮
,
蔡卫卫
,
张晶
,
梁亮
,
廖建辉
,
刘长鹏
. 自呼吸直接甲醇燃料电池膜电极的优化(英文)[J]. 电化学, 2010
, 16(2)
: 131
-136
.
DOI: 10.61558/2993-074X.2050
The structure and performance of MEA were optimized by tailoring the catalyst layer,cathodic microporous layer ( MPL) ,anodic MPL and membrane,with the considerations of unique characteristics of airbreathing direct methanol fuel cell ( DMFC) such as methanol crossover and cathode flooding. It was found that high catalyst loading could suppress the methanol crossover effectively,but too high catalyst loading can lead to high mass transport resistance. Hydrophobic anodic MPL with 30% ( by mass) PTFE could facilitate the CO2 bubble detachment,which decreased the methanol concentration gradient and suppressed the methanol crossover accordingly. When Nafion 115 was used as membrane,methanol crossover was severe,while Nafion 117 was used, the water in cathode could not be effectively back-flowed to the anode by hydraulic pressure. For considerations of complicated interactions and trades-off between the water and methanol crossover effects,the optimized MEA showed peak power density of 33 mW·cm-2 at ambient conditions,the best working methanol concentration was 4 mol·L-1.
[1]Arico A S,Srinivasan S,Antonucci V.DMFCs:from fun-damental aspects to technology development[J].Fuel Cells,2001,1:133-161.
[2]Dillon R,Srinivasan S,Arico A S,et al.International ac-tivities in DMFC R&D:status of technologies and poten-tial applications[J].J Power Sources,2004,127:112-126.
[3]Kamarudin S K,Daud W R W,Ho S L,et al.Overview on the challenges and developments of micro-direct methanol fuel cells[J].J Power Sources,2007,163:743-754.
[4]Kim D,Cho E A,Hong S A,et al.Recent progress in passive direct methanol fuel cells at KIST[J].J Power Sources,2004,130:172-177.
[5]Guo Z,Faghri A.Development of planar air breathing di-rect methanol fuel cell stacks[J].J Power Sources,2006,160:1183-1194.
[6]Pan Y H.Advanced air-breathing direct methanol fuel cells for portable applications[J].J Power Sources,2006,161:282-289.
[7]Chan Y H,Zhao T S,Chen R,et al.A small mono-polar direct methanol fuel cell stack with passive operation[J].Journal of Power Sources,2008,178:118-124.
[8]Baglio V,Stassi A,Matera F V,et al.Optimization of properties and operating parameters of a passive DMFC mini-stack at ambient temperature[J].J Power Sources,2008,180:797-802.
[9]Arico A S,Baglio V,Antonucci V.Direct methanol fuel cells:history,status and perspectives.In:Liu H S,Zhang J J,editors.Electrocatalysis of direct methanol fuel cells[M].Weinheim:Wiley-VCH,2009.1-78.
[10]Gogel V,Frey T,Yongsheng Z,et al.Performance and methanol permeation of direct methanol fuel cells:de-pendence on operating conditions and on electrode structure[J].J Power Sources,2004,127:172-180.
[11]Jiang R,Chu D.Comparative studies of methanol cross-over and cell performance for a DMFC[J].J Electro-chem Soc,2004,151:A69-A76.
[12]Nakagawa N,Abdelkareem M A,Sekimoto K.Control of methanol transport and separation in a DMFC with a porous support[J].J Power Sources,2006,160:105-115.
[13]Du C Y,Zhao T S,Yang W W.Effect of methanol cr-ossover on the cathode behavior of a DMFC:A half-cell investigation[J].Electrochim Acta,2007,52:5266-5271.
[14]Lu G Q,Wang C Y.Electrochemical and flow charac-terization of a direct methanol fuel cell[J].J Power Sources,2004,134:33-40.
[15]Lu G Q,Liu F Q,Wang C Y.Water transport through Nafion112membrane in DMFCs[J].Electrochem Sol-id-State Let,2005,8:A1-A4.
[16]Xu C,Zhao T S,He Y L.Effect of cathode gas diffusion layer on water transport and cell performance in direct methanol fuel cells[J].J Power Sources,2007,171:268-274.
[17]Jiang R,Chu D.Water Crossover:A challenge to DM-FC system I.Experimental determination of water crossover[J].J Electrochem Soc,2008,155:B798-B803.
[18]Ma L,Huang Y,Feng L,et al.Fabrication and optimi-zation of DMFC catalyst layers and membrane electrode assemblies.In:Liu H S,Zhang J J,editors.Electroca-talysis of direct methanol fuel cells[M].Weinheim:Wiley-VCH,2009.417-447.
[19]Peled E,Blum A,Aharon A,et al.Novel approach to recycling water and reducing water loss in DMFCs[J].Electrochem Solid-State Let,2003,6:A268-A271.
[20]Kim H,Oh J,Kim J,et al.Membrane electrode assem-bly for passive direct methanol fuel cells[J].J Power Sources,2006,162:497-501.
[21]Liu F,Lu G,Wang C Y.Low crossover of methanol and water through thin membranes in direct methanol fuel cells[J].J Electrochem Soc,2006,153:A543-A553.
[22]Xu C,Zhao T S.In situ measurements of water cross-over through the membrane for direct methanol fuel cells[J].J Power Sources,2007,168:143-153.
[24]Liu F,Wang C Y.Water and methanol crossover in di-rect methanol fuel cells-Effect of anode diffusion media.Electrochim[J].Acta,2008,53:5517-5522.
[25]Zawodzinski J T A,Derouin C,Radzinski S,et al.Wa-ter uptake by and transport through Nafion117mem-branes[J].J Electrochem Soc,1993,140:1041-1047.