On the processes of migration and diffusion in the systems with solid-state reagents

This paper deals with peculiarities of diffusion and migration in electrochemical systems with solid-state reagents (ESSSR). Contradictions of the diffusion model are analyzed. It is the difference of applied potentials and the corresponding electric field strength in the bulk solid phase and at the interfaces which is the primary driving force of charge transfer in ESSSR. The time characteristic of diffusion processes is not comparable to the duration of electrode processes at charging/discharging of batteries and especially electrochemical capacitors. In many real systems involving ESSSR, the process of diffusion in solid phase is absent. Examples of charge transfer processes in ESSSR (nickel hydroxide electrode, sparingly soluble quinoid compounds, Li+ intercalation in graphite, etc.) are considered, and the processes are explained using the Grothuss, tunnel and other migration mechanisms. It is shown in this paper that the linear relationship between peak currents in voltammetric curves and the square root of potential scan rate cannot be presented as an ultimate support of the diffusion model, but as а more universal property of ESSSR. In this aspect, the efficient diffusion coefficient, Deff, could be at best discussed, not to distort the ideas of charge-transfer migration mechanisms in the ESSSR

Self-Organized Heterocyclic Amines Films on Carbon Substrates for Photovoltaic Applications

Future technologies for organic photovoltaics include self-organization and self-assembly. Heterocyclic amines, namely sodium sulfacyl, clonidine, and cyanocobalamin, were deposited on four types of carbon-on-paper substrates by the self-organization assembly method. Each organic film was deposited in the chemical bath for 10, 20, 40, 60, and 90 min. Carbon substrates were thin layers of carbon composites deposited on Maestro paper. Compositions of carbon films of thicknesses about 20 mcm included graphitized carbon black “PureBlack@”and graphite “KGPS-1” as the permanent components, as well as activated carbon, magnetite, nanotubes, and needle graphite DBX-010 as variable components. Polyvinyl butyral (PVB) served as a binder for all of these composites. Morphological features of organic-carbon hybrids were investigated using optical microscopy MII-4 of 500 nm resolution with a SLR camera. The injection properties of the obtained hybrids were studied on standard equipment for current–voltage characteristics measuring. The thin organic films demonstrated the possibility of self-organization on various carbon substrates. The best grid morphology was determined for the optimal deposition time between 20 and 40 min with circular-type cells. The best injection properties correlated with the best morphology. These heterocyclic amines-on-carbon hybrids are promising structures for the formation of non-expensive and easily-fabricated solar cells

Novel Water-Based Paints for Composite Materials Used in Electromagnetic Shielding Applications

The development of materials offering electromagnetic interference (EMI) shielding is of significant consideration, since this can help in expanding the lifetime of devices, electromagnetic compatibility, as well as the protection of biological systems. Conductive paints used widely today in electromagnetic interference (EMI) shielding applications are often based on organic solvents that can create safety issues due to the subsequent environment problems. This paper concerned the development of eco-friendly conductive water-based paints for use in EMI-shielding applications. Graphene nanoplatelets, polyaniline emeraldine (PANI) doped with poly(styrene sulfonic acid) (PSS) or HCl or HBr and poly(3,4-ethylenedioxythiophene) poly(styrene sulfonic acid) (PEDOT:PSS) in various ratios were employed in a water base for developing the paints. The target was to develop homogeneous water-based paint-like fluid mixtures easily applied onto surfaces using a paint brush, leading in homogeneous, uniform, opaque layers, draying fast in air at room temperature, and having quite good electrical conductivity that can offer efficient EMI-shielding performance. The results of this parametric trial indicated the optimum compositions leading in paints with optimized properties that can result in uniform, homogeneous, and conductive layers up to a thickness of over 500 μm without deformation and cracking, offering attenuation of up to 60 dBs of incoming GHz electromagnetic radiation. In addition, the structural and morphological characteristics of these paints were studied in detail

Development of novel SOlid Materials for high power Li polymer BATteries (SOMABAT). Recyclability of components.

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