Electrolytic Activation of Iron Electrodes in Aqueous Potassium Hydroxide

Abstract

Effects of hydrogen absorption-desorption on the electrolytic activation of iron electrodes in 4. 7 N KOH solution were studied in order to obtain fundamental data for the preparation of the negative plate of a sintered-type alkaline storage battery.
The results were summarized as follows : (1) The rest potential was significantly less noble in the electrolytic reduction at -1.30 V and showed a nearly constant potential of -0.990 V when electrolytic reduction was carried out for more than 10 min.
(2) The current-potential curves and potential-time curves at constant current showed that a new peak probably due to the oxydation of absorbed atomic hydrogen appeared at -0. 85 V on anodic scanning from the hydrogen evolution potential. Iron electrodes activated by the adsorption-desorption of hydrogen exhibited an increased discharge capacity. The electrode potential at the initial stage of discharge decreased with drop in the charging potential. This caused higher discharge capacities.
( 3 ) When the iron electrodes were activated by electrolytic reduction, a swelled or disintegrated surface were observed on electronmicrophotograph, but no distinct change in X-ray diffraction pattern was found.