A. Zuttel et al., INFLUENCE OF ELECTRODE THICKNESS ON CHARGE DISCHARGE BEHAVIOR OF AB(5)-TYPE METAL HYDRIDE ELECTRODES, Journal of alloys and compounds, 221, 1995, pp. 207-211
Reversible alkaline batteries that use metal hydride alloys require a
compacting procedure for fabricating the negative electrode. This is b
ecause the intermetallic compounds used as the active material are bri
ttle and disintegrate into powder upon hydride formation. The charge-d
ischarge kinetics are expected to depend on the reaction mechanism and
on the electrode morphology. The resistance of an electrode can be di
vided into the following series resistances: the reaction resistance,
given by the surface composition of the alloy and the real surface are
a of the alloy grains, and the resistances due to the ionic conductivi
ty of the electrolyte and the electrical conductivity of the metal hyd
ride bed; these strongly depend on the porosity and the geometry of th
e electrode. The total resistance defines the kinetic behaviour and th
e loss of energy (Joule heating) during cycling. We have investigated
the influence of the electrode thickness on the overpotential during c
harge and discharge. The overpotential is described as a function of t
he discharge time and thickness of the electrode.