Questions concerning the interrelationship between the structure of nickel hydroxides used in alkaline batteries and their electrochemical activity are discussed. A great role in the nickel hydroxide electrode (NHE) activation played by the increase of the depth of the transition higher nickel hydroxides ---, ~-Ni(OH)2 during NHE discharging is shown. The latter can be achieved by modifying the higher nickel hydroxide structure. In particular, the cobalt(II) hydroxide additive enables this modification during NHE charging forming the fragments of the CoHQ structure embedded into the crystalline lattice, which leads to the inhibition effects during the transition phase ~-Ni(OH)2--~ ~-NiOOH and to some certain types of the crystalline lattice disorder facilitating the reverse transition to the ~-Ni(OH)2 structure during NHE discharging. It has been shown that the ~-NiOOH structure modification can be achieved by various means. In particular, some positive effects increasing the NHE reversibility are observed in the presence of the inert zinc hydroxide additive, as well as some portion of stable anions incorporated into the ~-Ni(OH)~ structure forming H-bonds with the layers of the nickel hydroxide crystalline lattice.
Miissbauer parameters for ferric hydroxo forms in alkaline matrices, ferric oxyhydroxide and its admixture at the nickel hydroxide electrode surface as well as for ferric hydroxo species adsorbed at nickel hydroxides from strongly alkaline solutions have been compared. The feasibility of transmission Miissbauer spectra acquisition for the adsorbed species in the presence of dissolved forms (e.g. in sir#) is based on the principle that the latter give no Miissbauer effect at room temperature owing to their diffusional mobility, while the former, being fixed at the adsorbent surface, have been shown to exhibit a sufiicient resonant absorption. Tbe effects of adsorption and adsorbent surface state on the coordination of ferric hydroxo complexes as well as its hydrolytic destruction in water have been noted. Some questions connected with anodic oxygen evolution electrocatalysis by iron species involved in the anodic process at the nickel hydroxide electrode are also discussed.
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