Study On The Performance Of Carbon Nanotube Double Microporous Layer Micro Direct Methanol Fuel Cel

Micro Direct Methanol Fuel Cell(μDMFC)is a new device,which has advances in green and environmentally friendly with high energy density,high conversion efficiency,and simple structure.It has a wide range of application prospects in many mobile devices.However,there are still many technical problems in the practical research ofμDMFC,such as low effective reaction area in electrochemical reactions,low catalyst utilization rate,and low power density.In the research on improving cell performance,the porous layer in the membrane electrode plays a critical role in the internal electrochemical reactions of the cell.Lowering the impedance of the porous layer and increasing the reaction area of the catalyst in the membrane electrode can effectively improve the cell output performance.While a single micro-porous layer membrane electrode reduces internal impedance to a certain extent,it also limits the number of reaction sites for the catalyst.Multiple micro-porous layer membrane electrodes can enhance the three-phase interface of the reaction and allow the catalyst to react more efficiently,but it also increases some internal impedance.Therefore,improving the micro-porous layer of the membrane electrode should not increase its impedance while also avoiding reducing the efficiency of the catalyst utilization.To improve the performance of cell membrane electrodes,the improvement of the membrane electrode microporous layer is one of the most critical points.In this thesis,we propose the use of a new material,carbon nanotube(CNT),to increase the catalyst reaction area without increasing the internal impedance of the membrane electrode.Firstly,a novel improvement combining new materials and structural design was proposed.The exceptional material properties of carbon nanotubes were analyzed,and it was found that the dual microporous layer structure enhances reaction efficiency.Structural design and simulation analysis were performed on the dual microporous layer membrane electrode,and the optimized electrode was validated through theoretical analysis and simulation results,confirming that the dual microporous layer membrane electrode can enhance the working performance of the cell.Second,the membrane electrode was prepared through experiments.Microstructure characterization and pore size distribution tests were conducted on various components of the membrane electrode,and the experimental results showed that the dual microporous layer structure membrane electrode has larger porosity and pore size,providing more reaction sites for the catalyst.The pore size distribution test revealed a wider range of pore sizes and a greater number of larger pores in the dual microporous layer,which can improve the three-phase interface of the cathodic reaction and provide better continuity.Finally,a single cell was fabricated and subjected to electrochemical analysis.The impedance characteristics of the cell were analyzed,and it was found that the dual microporous layer structure exhibited lower mass transport impedance and external impedance compared to the single microporous layer structure,demonstrating that the dual microporous layer increased both mass transport efficiency and reaction efficiency.The peak power density of the carbon nanotube dual microporous layerμDMFC was 42.8m W/cm~2,a 31.6%improvement compared to the single microporous layerμDMFC.Additionally,theμDMFC with dual microporous layers exhibited higher discharge performance at different concentrations.