Determination of hydrogen diffusion coefficient in metal hydride electrode by modified Warburg impedance

摘要

Hydrogen diffusion coefficients in MlNi_(3.75)Co_(0.65)Mn_(0.4)Al_(0.2) metal hydride electrode as a function of depth of discharge (DOD) and temperature were evaluated with modified Warburg impedance which describes more precisely the practical diffusion behavior. It was found that hydrogen diffusion coefficient in this electrode increases with the increase in DOD at ambient temperature, and for this electrode with 50 percent DOD, hydrogen diffusion coefficient increases with the increase of temperature and the activation energy for hydrogen diffusion in it is 35 kJ mol~(-1).