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Type: Article × Subject: polyaniline ×

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    The First Products of Aniline Oxidation – SERS Spectroelectrochemistry
    (Weinheim : Wiley-VCH, 2019) Morávková, Zuzana; Dmitrieva, Evgenia
    There are different opinions on the first products of aniline oxidation throughout the scientific community. While electrochemists basically accept only linear oligomers with repeating units joint in para positions, chemists have proposed formation of various branched and polycyclic oligomers. It was also suggested that one of these structures, N-phenyl-phenazinium cation, is responsible for the adherence of polyaniline films to substrates. In this work, a surface enhanced Raman spectroscopic and spectroelectrochemical analysis of the species adsorbed onto gold surface in aniline-containing solution at pH 1 and 5 is presented. The influence of the pH value on the oligomer structure is declared. The results are discussed in the context of linear and branched/phenazine-like aniline oligomers. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Imperceptible Supercapacitors with High Area-Specific Capacitance
    (Weinheim : Wiley-VCH, 2021) Ge, Jin; Zhu, Minshen; Eisner, Eric; Yin, Yin; Dong, Haiyun; Karnaushenko, Dmitriy D.; Karnaushenko, Daniil; Zhu, Feng; Ma, Libo; Schmidt, Oliver G.
    Imperceptible electronics will make next-generation healthcare and biomedical systems thinner, lighter, and more flexible. While other components are thoroughly investigated, imperceptible energy storage devices lag behind because the decrease of thickness impairs the area-specific energy density. Imperceptible supercapacitors with high area-specific capacitance based on reduced graphene oxide/polyaniline (RGO/PANI) composite electrodes and polyvinyl alcohol (PVA)/H2SO4 gel electrolyte are reported. Two strategies to realize a supercapacitor with a total device thickness of 5 µm—including substrate, electrode, and electrolyte—and an area-specific capacitance of 36 mF cm−2 simultaneously are implemented. First, the void volume of the RGO/PANI electrodes through mechanical compression is reduced, which decreases the thickness by 83% while retaining 89% of the capacitance. Second, the PVA-to-H2SO4 mass ratio is decreased to 1:4.5, which improves the ion conductivity by 5000% compared to the commonly used PVA/H2SO4 gel. Both advantages enable a 2 µm-thick gel electrolyte for planar interdigital supercapacitors. The impressive electromechanical stability of the imperceptible supercapacitors by wrinkling the substrate to produce folds with radii of 6 µm or less is demonstrated. The supercapacitors will be meaningful energy storage modules for future self-powered imperceptible electronics.