Electrostatic Layer-by-Layer Deposition and Electrochemical Characterization of Thin Films Composed of MnO2 Nanoparticles in a Room-Temperature Ionic Liquid

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• 作者：T&acirc ; nia M. Benedetti ; Fernanda F. C. Bazito ; Eduardo A. Ponzio ; Roberto M Torresi
• 刊名：Langmuir
• 出版年：2008
• 出版时间：April 1, 2008
• 年：2008
• 卷：24
• 期：7
• 页码：3602 - 3610
• 全文大小：672K
• 年卷期：v.24,no.7(April 1, 2008)
• ISSN：1520-5827

文摘

Thin films of MnO₂ nanoparticles were grown using the layer-by-layer method with poly(diallyldimetylammonium)as the intercalated layer. The film growth was followed by UV-vis, electrochemical quartz crystal microbalance(EQCM), and atomic force microscopy. Linear growth due to electrostatic immobilization of layers was observed upto 30 bilayers, but electrical connectivity was maintained only for 12 MnO₂/PPDA bilayers. The electrochemicalcharacterization of this film in 1-butyl-2,3-dimethyl-imidazolium (BMMI) bis(trifluoromethanesulfonyl)imide (TFSI)(BMMITFSI) with and without addition of a lithium salt indicated a higher electrochemical response of the nanostructuredelectrode in the lithium-containing electrolyte. On the basis of EQCM experiments, it was possible to confirm thatthe charge compensation process is achieved mainly by the TFSI anion at short times (<2 s) and by BMMI and lithiumcations at longer times. The fact that large ions like TFSI and BMMI participate in the electroneutrality is attributedto the redox reaction that occurs at the superficial sites and to the high concentration of these species compared tothat of lithium cations.