Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage

We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe2O3) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the “pure” conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt4BF4 (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of charge–discharge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertion–expulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during charge–discharge processes

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

Conducting polymer nanocomposite-based supercapacitors

The use of nanocomposites of electronically-conducting polymers for supercapacitors has increased significantly over the past years, due to their high capacitances and abilities to withstand many charge-discharge cycles. We have recently been investigating the use of nanocomposites of electronically-conducting polymers containing conducting and non-conducting nanomaterials such as carbon nanotubes and cellulose nanocrystals, for use in supercapacitors. In this contribution, we provide a summary of some of the key issues in this area of research. This discussion includes some history, fundamental concepts, the physical and chemical processes involved, and the challenges that these nanocomposite materials must overcome in order to become technologically viable. Due to space limitations, this is not a complete review of all the work that has been done in this field and we have focused on common themes that appear in the published work. Our aim is that this chapter will help readers to understand the advantages and challenges involved in the use of these materials in supercapacitors and to identify areas for further development

MW assisted synthesis of LiFePO4 for high power applications

LiFePO4/C was prepared by solid-state reaction from Li3PO4, Fe3(PO4)2.8H2O, carbon and glucose in a few minutes in a scientific MW oven with temperature and power control. The material was characterized by X-ray diffraction, scanning electron microscopy and by TGA analysis to evaluate carbon content. The electrochemical characterization as positive electrode in EC- DMC 1 M LiPF6 was performed by galvanostatic charge–discharge cycles at C/10 to evaluate specific capacity and by sequences of 10 s discharge-charge pulses, at different high C-rates (5-45 C) to evaluate pulse-specific power in simulate operative conditions for full-HEV application. The maximum pulse-specific power and, particularly, pulse efficiency values are quite high and make MW synthesis a very promising route for mass production of LiFePO4/C for full-HEV batteries at low energy costs

A three-dimensional carbon-coated LiFePO4 electrode for high-power applications

The fabrication process of a new, threedimensional carbon-coated LiFePO4 electrode by sol\u2013gel synthesis in situ on interconnected conducting fibers of carbon paper is described. This three-dimensional structure ensures overall electrode conductivity, facilitates lithium diffusion in and out of LiFePO4 particles and, hence, enables good cycling stability at 1C-rate and maximum pulse-power values that exceed those of planar LiFePO4 electrodes at high electrode loading

[Dysplasia epiphysealis hemimelica].

The Authors present 9 patients affected by Dysplasia Epiphysealis Hemimelica with a mean follow-up of 11 years (range 5 years-21 years). The Authors confirm the benignity of the disease and report the variability of the clinical evolution of this rare type of osteochondrodysplasia. Besides cases with spontaneous evolution characterized by no clinical evidence of the disease, there are cases that require surgical removal of the osteochondromas and, sometimes, corrective interventions because of axial deviations and/or limb discrepancy

Batterie al litio per dispositivi biomedicali

Gli avanzamenti della ricerca nel campo delle batterie al litio primarie e secondarie, sotto la pressante richiesta di mercato, hanno contribuito enormemente alla miniaturizzazione dei dispositivi biomedicali ed alla loro impiantabilità. In questo articolo viene data una breve panoramica su alcune batterie che hanno permesso lo sviluppo di dispositivi biomedicali sempre più sofisticati e che per questo motivo giocano una parte essenziale e determinante nel miglioramento della qualità della vita