| This paper, the first of a series to develop high-capacity and high-performance nickel electrode, studied crystal structures and electrochemical reactions of electrochemically precipitated nickel hydroxides. X-ray diffraction pattern (XRD) and thermogravimetric-differential thermal analysis (TG-DTA) showed that electrochemically precipitated nickel hydroxide is a turbostratic α-Ni(OH)₂having intercalated H₂O, NO₃, and it transforms into the more stable βNi(HO)₂ in KOH solution, which contains no intercalated H₂O, NO₃, Cyclic voltammetry showed that α-Ni(OH)₂ has a higher change capacity and more electrochemically active than β-Ni(OH)₂. The charge capacity of nickel hydroxide decreased dramatically at the initial stage of the transformation and its rate of decrease slowed down with lowering KOH concentration. However, the anodic peak potential shifted gradually during the transformation. The results was explained in terms of the concentration of intercalated anions in nickel hydroxide and OH in KOH solution. |
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