Air-Breathing Laminar Flow-Based Direct Methanol Fuel Cell with Alkaline Electrolyte

Abstract

Microfuel cells have the potential to achieve higher energy densities than batteries and have thus received intense investigation as a power source for a wide range of portable applications. Extensive research efforts are focused on the development and miniaturization of promising fuel cell technologies, including direct methanol fuel cells DMFCs and polymer electrolyte membrane-based fuel cells PEMFCs, operated with hydrogen/oxygen. 1-3 In most fuel cells, a polymer electrolyte membrane such as Nafion allows protons to diffuse from the anode to the cathode, while trying to prevent fuel molecules from diffusing across and mixing with oxygen at the cathode. Poor performance or a lack of selectivity by the membrane leads to a key performance-limiting process called fuel crossover that has plagued the PEM-based fuel cells. In addition to fuel crossover, cathode flooding and anode dry-out water management due to osmotic drag of water molecules associated with protons diffusing from the anode to the cathode, as well as due to the formation and consumption of water at the cathode and anode, respectively, impedes the performance and commercial implementation of these fuel cells. 4