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Poly(3,4-ethylenedioxithiophene)/poly(styrene sulphonate) (PEDOT/PSS) aqueous dispersions were mixed with aqueous gold nanoparticle and aqueous silver nanoparticle colloids. PEDOT/gold nanoparticles (Au NP) and PEDOT/silver nanoparticles (Ag NP) films were obtained by solvent casting the corresponding aqueous solutions. The nanocomposite films showed the optical characteristics associated with both the surface plasmon absorption resonance of the metal nanoparticles and the excitation of the bipolaron band of the conducting polymer. As an interesting application we demonstrate the use of metal nanoparticles to tune the color of PEDOT based electrochromic films from blue to violet in the case of Au NP or green in the case of Ag NP.

Abstract: A new family of polymeric ionic liquids having pyrrolidinium cation pendant units was synthesized from commercially available poly(diallyldimethylammonium) chloride. A simple anion exchange procedure was applied to the poly(diallyldimethylammonium) chloride using different salts such as LiTFSI, KPF6, LiBF4 and NaDBSA. The anion exchange reaction was quantitative as confirmed by NMR, FT-IR and titration experiments. Among these polymers, poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (TFSI) showed excellent performance as polymer matrix for polymer electrolyte compositions together with pyrrolidinium ionic liquid and lithium salt having a similar TFSI counter-anion. In this sense, free standing mechanically stable transparent polymer films showing an ionic conductivity higher than 10−4 Scm−1 at room temperature were prepared and characterized. Furthermore, the polymer electrolytes presented a wide electrochemical stability window (7.0V) which makes them interesting candidates for solid-state lithium batteries. [Copyright &y& Elsevier]

BatteriesThe use of immiscible electrolytes would make the removal of membranes from batteries possible. In their Communication on page 12460 ff. R. Marcilla and co‐workers demonstrate such a “proof‐of‐concept” battery. [ABSTRACT FROM AUTHOR]

Abstract Chemical functionalization of nanocarbons is an important strategy to produce electrochemical systems with higher energy/power density by generating surface functional groups with additional faradaic contribution, by increasing their surface area and correspondent capacitive contribution and by improving compatibility with aqueous electrolytes and other active materials, such as pseudocapacitive metal-oxides. Here we present an electrochemical method to simultaneously swell and functionalize large electrodes consisting of fabrics of macroscopic fibers of carbon nanotubes that renders the material hydrophilic and produces a substantial increase of specific capacitance and energy density in aqueous electrolytes. Through in-depth characterization of the carbon nanotube fibres (CNTF) by Raman spectroscopy, transmission electron microscopy, X-ray photoelectrocn spectroscopy (XPS) and small-angle X-ray scattering (SAXS) we identify various contributions to such improvements, including surface oxidation, tubular unzipping, debundling and inter-bundle swelling. Changes in hydrophilicity of functionalized CNTF are determined by analyzing the dynamics of spreading of polar and nonpolar liquids in the electrodes. The extracted contact angles and polar and dispersive surface energy components for different treatment conditions are in agreement with changes in dipole-moment obtained by XPS. Finally, functionalized CNTF electrodes were employed in current collector-free solid flexible supercapacitors, which show enhanced electrochemical properties compared to as-produced hydrophobic ones. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Highlights • NiMnO 3 -rGO nanocomposite were synthesized via a facile hydrothermal route followed by a thermal treatment. • The effect of hybridization was electrochemically investigated on energy storage performance of the material. • NiMnO 3 -rGO nanocomposite exhibited a high capacity of 91 mAh g−1. • The nanocomposite demonstrated a high energy density of ∼24 Wh kg−1 in integration with rGO. Abstract Demand for more efficient and ecofriendly energy storage systems arouse research efforts in seeking to develop new energy materials with promising properties. In this regard, mixed transition metal oxides have recently attracted great attention due to their improved electrochemical and electrical properties in comparison with simple oxides. Herein, NiMnO 3 and their composites with reduced graphene oxide (NiMnO 3 -rGO) were synthesized via a facile hydrothermal route, followed by a thermal treatment and their electrochemical properties have been evaluated as electrode materials for hybrid energy storage devices. The prepared samples were characterized by using X-ray diffraction (XRD), Raman spectroscopy, Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and N 2 adsorption measurements. The energy storage behavior of the samples was investigated using different electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. Accordingly, a NiMnO 3 -rGO nanocomposite showed a high capacity of 91 mAh g−1 at a scan rate of 5 mV s−1, 48% higher than that of the pure NiMnO 3 sample (47.7 mAh g−1). Furthermore, this nanocomposite was integrated as a positive electrode with reduced graphene oxide nanosheets as the negative electrode in an aqueous hybrid energy storage device. This system displayed a high specific energy of 23.5 Wh kg−1 and a maximum specific power of 7.64 kW kg−1. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, we report the microstructural characterization and the electrochemical performance of six activated carbons with varied textural properties. Activated carbons were investigated in terms of specific surface area, pore size distribution, surface chemistry and electrochemical behaviour in acidic, neutral and organic electrolytes. For this purpose, N2 adsorption isotherms, thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR) and cyclic voltammetry (CV) techniques were used. Electrochemical properties of symmetric supercapacitors using these carbons were investigated by galvanostatic charge–discharge experiments and electrochemical impedance spectroscopy (EIS). Differences in textural properties of the activated carbons were analysed and correlated with their electrochemical behaviour indicating that mesoporous carbons of high surface area are promising materials for high power applications, whereas microporous carbons with higher specific capacitances would be preferred for high energy and medium power applications. [Copyright &y& Elsevier]