کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
186213 | 459609 | 2014 | 8 صفحه PDF | دانلود رایگان |
• Infrared spectra were obtained for three carbon|ionic liquid interfaces.
• The carbon electrodes have different electrochemical and infrared spectra.
• The thin carbon film electrodes have great potential for in situ infrared studies.
• Supercapacitor cell voltage limiting reactions were solved.
Three different carbon materials were studied in very dry 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) ionic liquid using infrared and electrochemical spectroscopy methods. Advantages of in situ infrared measurements with magnetron sputtered thin carbon films are demonstrated over thicker porous carbide-derived carbon and pyrolytic graphite electrodes. Differences in the double layer structure exist for the three carbon materials, confirmed by the different shape of capacitance-potential curves and infrared spectra. It was established that imidazolium cation dimerizes at potential E < −2 V (vs. Ag|AgCl wire in the same ionic liquid), whereas anion as well as cation decomposition takes place at E > +1.6 V. An explanation is given why EMImBF4 with a potential window of 4.1 V for the carbon film electrode gives symmetric supercapacitor voltage of only 2.8 V.
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Journal: Electrochimica Acta - Volume 125, 10 April 2014, Pages 183–190