Thesis
Characterization of a microfluidic based direct-methanol fuel cell
Master of Science (MS), Washington State University
2008
Handle:
https://hdl.handle.net/2376/105694
Abstract
Increased demand for portable power has given new interest in research of small scale fuel cells. To meet this demand a new fuel cell type has emerged as an excellent system for micro scale application, the Laminar Flow Fuel Cell, LFFC. LFFC's are microfluidic based devices that can operate without a membrane, using laminar fluid mechanics to separate the fuel cell half reactions. In this thesis a direct methanol laminar flow fuel cell is fabricated and studied both experimentally and analytically. The overall device performance is first briefly studied for stability and operating behavior. The characterization is done with performance curves and by monitoring open circuit potential. Some instability is found as well as performance trends based on methanol concentration, reactant flow rate, and electrolyte strength. The anode and cathode limitations are compared and it is found that the anode limitations are equivalent or greater. The anode limitations have not been given as much attention as the cathode limitations. Therefore, the direct methanol anode is isolated in this work and studied in further detail. Anode polarization and electrochemical spectroscopy are used to better understand the observed behavior. The stability, methanol concentration effect, reactant flow rate effect, and electrolyte strength effect are the salient behaviors evaluated. The results show that the methanol oxidation kinetics is greatly affected by these parameters. It is concluded that this relationship is due to a change in electric double layer structure. To better illustrate the role of the electric double layer an analytical model is used to simulate the behavior of the anode. The important results are the demonstration of the poor stability of the laminar flow fuel cells, the adverse effect of methanol concentration and electrolyte flow rate on methanol oxidation kinetics, the dramatic benefit of a strong supporting electrolyte. This shows that the flowing electrolyte stream should be optimized just as any electrolyte would be in other fuel cell systems. It also shows the important consideration of the electric double layer and the roll it can play in fuel cell performance.
Metrics
1 File views/ downloads
18 Record Views
Details
- Title
- Characterization of a microfluidic based direct-methanol fuel cell
- Creators
- Isaac Benjamin Sprague
- Contributors
- Prashanta Dutta (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Identifiers
- 99900525112501842
- Language
- English
- Resource Type
- Thesis