- Electrochemical template synthesis of advanced Ni(OH)2/PVA films for electrochromic devices hal link

Auteur(s): Kotok V. a., Kovalenko V.L., Kovalenko P.v., Solovov V.a., Deabate S., Medhi Amhad, Bantignies J.-L., Henn F.

(Article) Publié: Journal Of Engineering And Applied Sciences, vol. 12 p.3962 (2017)

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The use of electrochemical template synthesis for the formation of electrochromic composite nickel hydroxide/PVA films with poor inside stress, effective adhesion to substrate and high optical and electrochemical properties is proposed.Influence of the deposition current density and of the amount of PVA on the structure, surface morphology and transparency of the electrodeposit films is investigated. It is thus concluded that the optimal current density is 0.625 mA/cm2 for the pure Ni(OH)2 film whereas the optimal concentration of PVA is 5% weight is. Overall, the electroplated Ni(OH)2/PVA films exhibit an X-ray amorphous structure, due to the Ni(OH)2 particle growth in the nano-size cells of the 3D network of the PVA template. Surface morphology of films, deposited with the template synthesis, is investigated by SEM. The film electrodepositing rate by template synthesis was estimated around the 3.87 μm/h at the current density of the 0.625 mA/cm2. Template incorporating into the nickel hydroxide film has been proved by EDX analysis. Electrochemical and electrochromic properties of films, deposited by electrochemical template synthesis and dried at 20 °C and 90 °C, have been investigated. It was shown that both types of films have high properties (charge/discharge and colorization-bleaching processes). But films, dried at 20 °C, has the best electrochemical properties and larger colorization depth, however the colorization/bleaching process has larger reversibility for the sample dried at 90 °C