Ph.D. Proposal Presentation by Laam Angela Tse
Friday, September 24, 2004
(Dr. David W. Rosen, Chair)
"Membrane Electrode Assembly (MEA) Design for Power Density Enhancement of Direct Methanol Fuel Cells (DMFC)"
Micro-direct methanol fuel cells (µ-DMFC) can be the power supply solution for the next generation of handheld devices. The applications of the µ-DMFCs require them to have high compactness, high performance, light weight, and long life. In this proposal, different approaches are introduced to enhance the power density of the direct methanol fuel cell (DMFC) for portable devices. Patterning the membrane electrode assembly (MEA) from 1-D planar design to 2-D corrugated structures can greatly increase the power generation with very modest overall volume increases. Increasing the methanol feed concentration can reduce the fuel tank volume without reducing life. However, the commercially available Nafion solid electrolyte membranes allow methanol crossover at methanol feed concentration of greater than 2M, which can severely impact power production. A multiple-anode MEA design is proposed to reduce the methanol crossover problem by providing extra reaction sites for methanol oxidation to take place at the anodes. The performance of the MEA integrated with multiple anodes and patterned with corrugations will also be investigated to demonstrate the performance of the MEA with the integrated features. Finally, the geometric analysis of different fuel cell stacking configurations for different MEA manifolds will also be investigated to decrease the overall stacking volume of the DMFC system. Analytical models will be developed for geometric analysis of different MEA manifold geometries and stacking configurations. The performance of the DMFC will be evaluated by performing experiments on the customized MEAs and solving some analytical models of electrochemical reactions numerically using finite element method (FEA).