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A recent assessment (Giovannelli, G., D'Urzo, L., Maggiulli, G., Natali, S., Pagliara, C., Sgura, I. & Bozzini, B. 2010. Journal of Solid State Electrochemistry, 14: 479–94.) of the corrosion state...

We demonstrate the fabrication of free-standing polymeric nanocomposite films, which present magnetic and electrically conductive anisotropic properties. Magnetically functionalized carbon nanofibers are dispersed in a polymeric solution and, upon casting under a weak external magnetic field, are easily oriented and permanently assembled in a head-to-tail orientation in the polymer film during solvent evaporation. Magnetic and conductive property studies reveal that the resulting films have a high degree of anisotropy in both cases, thus allowing their use in functional complex devices. As a proof of concept, we demonstrate the potential application of these films as flexible THz polarizers. The detailed study shows that very high attenuation values per unit film thickness and fiber mass concentration are achieved, paving thus the way for cost-effective fabrication of substrate-free systems that have advantage over conventional devices realized so far.

Electrically conductive and self-cleaning superhydrophobic films (water contact angles >160°, droplet roll off angles

Freely-standing and flexible films (0.075 to 9 mm in thickness) of electrically conducting polypyrrole were synthesised via anodic electrodeposition onto a stainless steel substrate from methanesulphonic acid under stirred conditions at 295 K. Cyclic voltammetry was used to studythe effect of pyrrole monomer concentration (0.01 to 1.0 mol dm-3) and methanesulphonic acid level (1.0 to 6.0 mol dm-3) on the formation of polypyrrole films. The films were prepared for deposition times of 30–240 s at constant current densities of 1 to 15 mA cm-2. The ionic conductivity of freely-standing polypyrrole membranes in aqueous methanesulphonic acid was studied. Scanning electron microscopy was used to image the surface microstructure. The polypyrrole films, which were prepared in the oxidised (methanesulphonate doped), conductivestate, showed an ionic area resistance as low as 10 ohm cm2. The films were readily doped with the methanesulphonate anion and the membrane ionic conductivity was dependent on the electrolyte composition used for their deposition. In the presence of anodic oxygen evolution, thefilms showed a ‘template-free’ porosity due to film growth around the bubbles.

Metal–air batteries are becoming of particular interest, from both fundamental and industrial viewpoints, for their high specific energy density compared to other energy storage devices, in particular the Li-ion systems. Among metal–air batteries, the zinc–air option represents a safe, environmentally friendly and potentially cheap and simple way to store and deliver electrical energy for both portable and stationary devices as well as for electric vehicles. Zinc–air batteries can be classified into primary (including also the mechanically rechargeable), electrically rechargeable (secondary), and fuel cells. Research on primary zinc–air batteries is well consolidated since many years. On the contrary, research on the electrically rechargeable ones still requires further efforts to overcome materials science and electrochemical issues related to charge and discharge processes. In addition, zinc–air fuel cells are also of great potential interest for smart grid energy storage and production. This review aims to report on the latest progresses and state-of-the-art of primary, secondary and mechanically rechargeable zinc–air batteries, and zinc–air fuel cells. In particular, this review focuses on the critical aspects of materials science, engineering, electrochemistry and mathematical modeling related to all zinc–air systems.

This paper reports on the reactivity of cyanide ligands released from Ag(I) cyanocomplexes during electrodeposition at very negative potentials. The study is based on in-situ surface-enhanced Raman spectroscopy (SERS) measurements performed during Ag electrodeposition from H2O and D2O based-electrolytes in order to pinpoint isotopic shifts. The investigation is complemented by electrochemical measurements – electrochemical impedance spectrometry (EIS) and cyclic voltammetry (CV) – as well as by SEM micrography. Surface-enhanced Raman spectroscopy spectroscopy disclosed details of the cathodic reactivity of adsorbed cyanide yielding amine that are typical of very negative polarisations and had not been observed in previous studies. The formation of cathodic films resulting from cyanide reactivity and giving rise to cathodic passivation and the cathodic reactivation corresponding to the increase in formation rate at the most negative investigated potentials have also been followed by potential-dependent EIS...

Interaction of polyethylene oxide (PEO) with transition metal triflates is a newly emerging research area due to its numerous application fields, such as thin-film power conversion devices and sensors. In the present study, we demonstrate, for the first time, that PEO can solvate silver triflate organic salts in large quantities when formic acid is used as a common solvent for both. Nanocomposites with unique structural and electrical properties are fabricated by simply drop casting formic acid solutions of PEO and silver triflate salts. We present a detailed experimental study on the characterization of morphological and electrical properties of PEO-silver triflate nanocomposite films as a function of silver triflate concentration and discuss their potential applications as humidity sensors. In particular, by increasing the concentration of the salt in the initial solution the morphological features of the formed nanocomposites can be varied from well defined microcrystals to amorphous nanofibers. Of special interest are the nanocomposite films fabricated from a 1:1 (PEO-unit:Ag(+)) molar ratio, since they consist of self-assembled nanofibrillar structures, which exhibit good electrical conductivity as well as highly repeatable sensitivity towards humidity.

We demonstrate a simple and rapid way to deposit layers of polyaniline (emeraldine base) particles on flexible microtextured silicon carbide surfaces by contact charging them using a smooth dielectric rubber. Wetting of the layers by trifluoroacetic acid creates conductive, continuous polymeric films after drying. Pre-functionalization of the textured surfaces with anionic surfactants prevents particle coagulation during contact charging and decreases sheet resistance to metal-like levels (∼60 Ω/□). Conductivity of the films can be tuned by controlling the rate of acid evaporation. Conductive films are highly stable under ambient conditions and show no hysteresis when biased with zero delay-time.