Effects of Temperature on the Performance of the MmNi[sub 3.6]Co[sub 0.7]Mn[sub 0.4]Al[sub 0.3] Metal Hydride Electrode in Alkaline Solution

Abstract

In the present study, the electrochemical and hydrogen transport kinetic performance of the MmNi3.6Co0.7Mn0.4Al0.3 metal hydride electrode has been systematically investigated in the temperature range 0–60°C . The results show that the electrode reaction becomes more reversible and gets faster at higher temperatures. At low-discharge current densities, the charge transfer overpotential is greater than the diffusion overpotential, whereas at high-discharge current densities the diffusion overpotential becomes dominant. At medium-discharge current densities, there is a mixed control with a predominance of the mass-transport conditions at lower temperatures. The calculated kinetic parameters also show that the hydrogen desorption on the metal hydride electrode is easier than the hydrogen absorption into its alloy bulk. Activation energies for charge transfer and for hydrogen diffusion, as well as the hydrogen diffusion coefficients in the electrode, have also been estimated.

Hydrogen diffusion behavior in α-solid solution phase of LmNi3.55Co0.75Mn0.4Al0.3 metal hydride electrode—Effect of temperature

“…The obtained results were found to be consistent with the reported values for alloy electrodes with the same or similar composition at low concentration of hydrogen initially charged [9,14,[16][17][18]21,24,25]. Conversely, some reports suggest that the values of hydrogen diffusion coefficient are one or maybe two orders of magnitude lower or higher [8,10,11,13,15,[26][27][28]. This great discrepancy in the reported values of hydrogen diffusion coefficient in the alloy electrodes, even with the same composition, might be attributed to the following.…”

Low Temperature Characteristics of Hydrogen Storage Alloy LaMm-Ni4.1Al0.3Mn0.4Co0.45 for Ni-MH Batteries

“…The determined values of hydrogen diffusion coefficient at SOC = 1 (average ca. 2.5 × 10 −10 cm 2 /s) lay within the range observed for other hydrogen storage alloys of similar grain size [43][44][45].…”

Effect of temperature on behavior of perovskite-type oxide LaGaO3 used as a novel anode material for Ni-MH secondary batteries

“…The slope line of Ln D H versus 1/ T in Figure corresponds to the value of E a (117.46 kJ mol −1 ). This value is higher than those reported in literature for the conventional hydrogen storage alloys …”

“…This value is higher than those reported in literature for the conventional hydrogen storage alloys. [38][39][40][41] Potentiodynamic polarization technique was used to characterize the kinetic behavior of the working electrode after activation at different temperatures. The exchange current density (I 0 ) and the polarization resistance (R p ) are the effective parameters to estimate the electrocatalytic activity of the electrochemical reaction on the electrolyte/electrode interface.…”