Design of new MEA structure for Mciro Direct Methanol Fuel Cell

摘要

A novel double-catalyst layer MEA using CCM-GDE (Catalyst Coated Membrane, CCM; Gas Diffiision Electrode, GDE) fabrication method is provided. The double-catalyst layer is formed with an inner catalyst layer (in anode side: PtRu black as catalyst, in cathode side: Pt black as catalyst) and an outer catalyst layer (in anode side: PtRu/C as catalyst, in cathode side: Pt/C as catalyst). By study of the catalyst loading in the double-catalyst layer, an optimization of the catalyst layer structure is obtained, that is the cell may perform best when the ratio of the inner catalyst and outer catalyst is 1:1 (both in inner and outer catalyst layer, the catalyst loading is 1.5mg/cm~2). As the hydrophilicity and pore structure are important to the MEA performance, they are optimized by adding pore former and Nation in the GDL and outer catalyst layer, respectively. Thus three gradients from the PEM to the GDL are formed in the novel MEA: catalyst concentration gradient, porosity gradient and hydrophilicity gradient. These gradients may increase the mass transfer and quicken the electrochemistry reaction in MEA. The CCM-GDE technology may enhance the contact properties between the catalyst and PEM, and increase the electrode reaction areas, resulted in increasing the performance of the μDMFC.