Effect of Flow-Field Variation on Hydrogen Adsorption in a Carbon Electrode Integrated into a Modified Reversible Polymer Electrolyte Membrane Fuel Cell

Reversible polymer electrolyte membrane (PEM) fuel cells have attracted significant research attention in the last decade due to the associated benefits. However, flow-field design of the bipolar end plates, among various other parameters, largely affects its performance. Thus, the present paper focuses on determining hydrogen storage capacity of a typical activated carbon (aC) electrode employed in a reversible modified PEM fuel cell with varied designs of flow-field. Three flow-field orientations-pin-type, parallel, and interdigitated-are used and their performance is evaluated. The fabrication method of the electrode, reversible modified PEM fuel cell, and different orientations of micro flow channels is disclosed. The characterization of the employed aC electrode is done using scanning electron microscopy (SEM), x-ray diffraction analysis (XRD), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). The fabricated cells are tested by linear voltage sweep and results are recorded. The result analysis revealed that the interdigitated flow-field design leads to better distribution of the reactants and encourages higher hydrogen adsorption in the carbon electrode compared to the other flow-field designs under consideration. The electrochemical hydrogen storage capacity of the carbon electrode with interdigitated flow-field design is found to be 1.47 weight percentage (wt. %), whereas for parallel and pin-type designs, it stands at 1.40 wt. % and 1.36 wt. %, respectively. The obtained energy storage density is comparable with the commercially available metal hydride based compressed hydrogen canisters. It is surely a step forward toward developing a reversible PEM fuel cell with enhanced performance capable of storing the charge, like a battery, with many potential applications.