Microfluidic H2/O2 fuel cells for contaminant and electrode analysis

Alkaline fuel cells (AFCs) are promising power sources due to superior cathode kinetics as compared to acidic media and the ability to use inexpensive non-noble metal catalysts. However, carbonate formation from carbon dioxide in air has long been considered a significant hurdle for liquid electrolyte-based AFC technologies. Carbonate formation consumes hydroxyl anions, which leads to (i) reduced electrode performance if formed salts precipitate from solution and (ii) lowered electrolyte conductivity, which reduces cell performance and operating lifetime. We have used a microfluidic H2/O2 fuel cell as an analytical platform to determine the effects of the carbonate formation problem in alkaline fuel cells. The microfluidic fuel cell has modular components that can easily be swapped to test electrodes, electrolyte, or other aspects of the fuel cell. A reference electrode placed at the outlet allows for individual electrode analysis, which is not normally possible in conventional membrane-based fuel cells. In this thesis, it is demonstrated that AFC performance can be resilient to a broad range of carbonate concentrations. Furthermore, the effects of carbonate formation rates on projected AFC operational lifetime are determined. A quantitative method to analyze individual electrode performance using single electrode plots and the two parameters Rohmic and Vkinetic is also developed. Results demonstrated that losses from both electrodes are substantial in an alkaline fuel cell, and that ohmic and mass transport losses are shown to only significantly affect Rohmic. IR-corrections were used to isolate individual kinetic and mass transport losses at each electrode within the operating fuel cell. These findings demonstrate great potential to broaden the scope of fuel cell research.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Naughton, Matt

Contributors dc:contributor

• Kenis, Paul J.A.

• alkaline fuel cell
• reference electrode
• single electrode plots
• silver (Ag) cathode
• electrode degradation

Statement dc:rights

• Copyright 2011 Matt Naughton. All rights reserved.

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/24356

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/24356