Optimization of the deposition conditions for Ni(OH)2 films for electrochromic elements of “smart” windows
Journal Title: Восточно-Европейский журнал передовых технологий - Year 2019, Vol 2, Issue 5
Abstract
<p class="1">Thestudywasconductedinordertodeterminethe influenceoftwofactorsonelectrodepositionofNi(OH)<sub>2 </sub>films: concentrationofnickelnitratein the electrolyteanddrying stage between deposition and electrochemical and optical tests. For deposition, pure solutions of nickel nitrate without additives were used, so that the presence of the latter did not complicate the analysis of the data obtained.</p><p class="1">As a result, two series of films were prepared from electrolytes with nickel nitrate concentrations of 0.01, 0.1 and 1 M. The difference between the two series is the presence or absence of drying stage after deposition. Drying was conducted under mild conditions at room temperatures.</p><p class="1">Electrochemical and optical characteristics were evaluated by means of cyclic voltamperometry with simultaneous recording of changes in film transparency.</p><p class="1">As a result of analysis of the obtained data, it was found that uniform films with roughly equal thickness are obtained within the nickel nitrate concentration range from 0.01 to 0.1 M. For solutions with the nickel nitrate concentration of 1 М, deposition occurs with significant non-uniformity. A hypothesis was proposed, in which such behavior is explained by redistribution of current density over the electrode surface due to the high conductivity of the concentrated nickel nitrate solution. In turn, the redistribution of current density results in a significantly high current density on the electrode surface near the electrolyte-air boundary. Such an increase could result in shifting of the reaction front away from the electrode or formation of Ni(OH)<sub>2</sub> with high thickness. The latter would lose contact with the electrode and fall off.</p>It was also found that drying process has a significant effect on the structure and properties of the films. Drying process was also found to impact the appearance of nickel hydroxide films due to film cracking. It was also assumed that electrochemically deposited nickel hydroxide contains a large amount of crystal water
Authors and Affiliations
Valerii Kotok, Vadym Kovalenko
Keywords
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- EP ID EP666308
- DOI 10.15587/1729-4061.2019.162572
- Views 52
- Downloads 0
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