Steady and Pulsed Flow Performance Trends of Higher Concentration DMFCs

摘要

Direct methanol fuel cells (DMFCs) are a promising source of energy due to their potentially high energy density, facilitated fuel delivery and storage, and precluded fuel processing. However, DMFCs have several challenges which need to be resolved before they can replace existing energy sources. Some of these challenges include lower power density, relatively high cost, and uncertain reliability. These issues are all promoted, at least in part, by the methanol crossover phenomenon, wherein membrane permeability allows the undesirable species transport of methanol from the anode to the cathode. This phenomenon also causes the requirement of dilute fuel mixtures, which is undesirable from an energy density viewpoint. Prior research has shown that methanol crossover can be reduced by operating DMFCs in a transient mode. Thus, a study has been performed to investigate the impact of hydraulic pulsing (HP) at different operating conditions, such as fuel concentration, current density, and number-of-stoichs (NOS). Furthermore, the cell's performance is being characterized at different steady flow concentrations to highlight the impact of fuel dilution.