Mass transport is crucial to the performance of proton exchange membrane fuel cells,especially at high current densities.Generally,the oxygen and the generated water share same transmission medium but move towards opp...Mass transport is crucial to the performance of proton exchange membrane fuel cells,especially at high current densities.Generally,the oxygen and the generated water share same transmission medium but move towards opposite direction,which leads to serious mass transfer problems.Herein,a series of patterned catalyst layer were prepared with a simple one-step impressing method using nylon sieves as templates.With grooves 100μm in width and 8μm in depth on the surface of cathode catalyst layer,the maximum power density of fuel cell increases by 10%without any additional durability loss while maintaining a similar electrochemical surface area.The concentration contours calculated by finite element analysis reveal that the grooves built on the surface of catalyst layer serve to accumulate the water nearby while oxygen tends to transfer through relatively convex region,which results from capillary pressure difference caused by the pore structure difference between the two regions.The separation of oxidant gas and generated water avoids mass confliction thus boosts mass transport efficiency.展开更多
通过调控2种碳材料科琴黑[Ketjen Black EC-600JD(KB)]和黑珍珠[Black Pearls 2000(BP)]的比例,优化了室温下空气"自呼吸"式直接甲醇燃料电池膜电极集合体阴极微孔扩散层的孔结构,提高了氧气在阴极的传质,避免了液态水在阴极...通过调控2种碳材料科琴黑[Ketjen Black EC-600JD(KB)]和黑珍珠[Black Pearls 2000(BP)]的比例,优化了室温下空气"自呼吸"式直接甲醇燃料电池膜电极集合体阴极微孔扩散层的孔结构,提高了氧气在阴极的传质,避免了液态水在阴极的累积。实验结果表明,阴极微孔扩散层中BP的添加对电池性能有较大的影响。当阴极微孔扩散层中的KB和BP碳材料以质量比9∶1混合时,25℃、空气"自呼吸"条件下,直接甲醇燃料电池的最大功率密度达20.8×10-3W/cm2,电池具有好的稳定性。高的功率密度和好的稳定性可归属于少量BP的添加改善了阴极微孔扩散层的孔结构。展开更多
基金supported by the National Natural Science Foundation of China(21838003,91834301)the Shanghai Scientific and Technological Innovation Project(18JC1410600,19JC1410400)+2 种基金the Social Development Program of Shanghai(17DZ1200900)the Innovation Program of Shanghai Municipal Education Commissionthe Fundamental Research Funds for the Central Universities(222201718002)。
文摘Mass transport is crucial to the performance of proton exchange membrane fuel cells,especially at high current densities.Generally,the oxygen and the generated water share same transmission medium but move towards opposite direction,which leads to serious mass transfer problems.Herein,a series of patterned catalyst layer were prepared with a simple one-step impressing method using nylon sieves as templates.With grooves 100μm in width and 8μm in depth on the surface of cathode catalyst layer,the maximum power density of fuel cell increases by 10%without any additional durability loss while maintaining a similar electrochemical surface area.The concentration contours calculated by finite element analysis reveal that the grooves built on the surface of catalyst layer serve to accumulate the water nearby while oxygen tends to transfer through relatively convex region,which results from capillary pressure difference caused by the pore structure difference between the two regions.The separation of oxidant gas and generated water avoids mass confliction thus boosts mass transport efficiency.
文摘通过调控2种碳材料科琴黑[Ketjen Black EC-600JD(KB)]和黑珍珠[Black Pearls 2000(BP)]的比例,优化了室温下空气"自呼吸"式直接甲醇燃料电池膜电极集合体阴极微孔扩散层的孔结构,提高了氧气在阴极的传质,避免了液态水在阴极的累积。实验结果表明,阴极微孔扩散层中BP的添加对电池性能有较大的影响。当阴极微孔扩散层中的KB和BP碳材料以质量比9∶1混合时,25℃、空气"自呼吸"条件下,直接甲醇燃料电池的最大功率密度达20.8×10-3W/cm2,电池具有好的稳定性。高的功率密度和好的稳定性可归属于少量BP的添加改善了阴极微孔扩散层的孔结构。
