Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

Abstract: The possibility of substituting Pt/C with the hydrogen storage alloy MlNi_3.6Co_0.85Al_0.3Mn_0.3 as the anode active material of a proton exchange membrane fuel cell system has been analyzed. The electrochemical properties indicate that a much more electrochemically active anode is obtained by impregnating the active material loaded anode in a Nafion proton conducting polymer. Such performance improvement might result from the increase of three-phase boundary sites or length in the gas diffusion electrode where the electrochemical reaction occurs. The experimental data revealed that the membrane electrode assembly (MEA) shows better results when the anode active material, MlNi_3.6Co_0.85Al_0.3Mn_0.3, is treated with a hot alkaline KBH₄ solution, and then chemically coated with 3 wt.% Pd. The MEA with the aforesaid modification presents an enhanced surface capability for hydrogen adsorption, and has been studied by molecular beam-thermal desorption spectrometry.