| Title |
Kinetic Parameter Analysis of Hydrogen Diffusion Reaction for Hydrogen Storage Alloy of Fuel Cell System |
| Keywords |
Ni-MH battery ; MmNi3.55Co0.75Mn0.4Al0.3 ; Single Spherical Particle ; Microelectrochemistry ; Hydrogenation/dehydrogenation |
| Abstract |
Electrochemical hydrogenation/dehydrogenation properties were studied for a single particle of a Mm-based (Mm：misch metal) hydrogen storage alloy (MmNi3.55Co0.75Mn0.4Al0.3) for fuel cell and Ni-MH batteries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, and the potential-step experiment was carried out to determine the apparent chemical diffusion coefficient of hydrogen atom (Dapp) in the alloy. Since the alloy particle we used here was a dense, conductive sphere, the spherical diffusion model was employed for data analysis. Dapp was found to vary the order between 10?? and 10?¹?[㎠/s] over the course of hydrogenation and dehydrogenation process. Compared with the conventional composite film electrodes, the single particle measurements using the microelectrode gave more detailed, true information about the hydrogen storage alloy. |