250 research outputs found
Introduzione
No full textL'autore introduce il tema delle riforme promosse dalla l.d. n. 124/2015 individuandone le principali criticità
Sn-Co nanowire-based anodes for lithium-ion batteries
No full textThe demand of improvement in lithium-ion battery technology in terms of specific capacity and safety has stimulated the search for anode materials alternative to graphite. Among them, tin-based materials have been widely studied because tin can intercalate lithium up to atomic ratio Li/Sn of 4.4 to deliver a impressive specific capacity of 993 mAhg−1 (while graphite gives 372 mAhg−1). Unfortunately the high volume change of about 300%, which is related to the insertion/removal of lithium, causes the alloy pulverization and loss of electric contact that causes a poor cycle life. The synthesis of nanometric materials, intermetallic compounds and carbon composites are strategies that have been pursued to reduce this drawback.
In the present study, nanowires of SnCo amorphous alloy grown inside the channels of polycarbonate membrane by potentiostatic deposition were tested as anode for lithium-ion batteries with galvanostatic charge/discharge cycles, demonstrating a capacity corresponding to tin theoretical one stable for over 30 cycles. Even results of nanowires of the same alloy grown on alumina membrane are reported as comparison1.
Reference
1. G. Ferrara, C. Arbizzani, L. Damen, R. Inguanta, S. Piazza, C. Sunseri, M. Mastragostino, Nanostructured anode and cathode materials for Li-ion batteries, CIMTEC 2010 5th Forum on New Materials, Montecatini, Italy, June 13-18, 201
Polybithiophene as positive electrode in solid-state polyethylene oxide—LiClO4 lithium rechargeable battery
No full textCyclability features of an all solid-state lithium polybithiophene battery with PEO20LiClO4 polymer electrolyte was investigated at 70°C working temperature. Although the capacity values of the solid device are lower than those of the comparable one with liquid electrolyte, the cyclability performances are promising and the cycle life is satisfactory. The shelf-life of the solid battery was also investigated. The self-discharge rate is fast at 70°C but is not appreciable at room temperature. © 1990
Forma di governo, Presidente di Regione e Giunta regionale tra giurisprudenza costituzionale e attuazione statutaria
No full textIl contributo si inserisce nel Volume dal titolo "Lineamenti di Diritto Costituzionale della Regione Emilia-Romagna", curato dai Professori Michele Belletti, Franco Mastragostino e Luca Mezzetti. L'Autore del contributo ha dato dettagliatamente conto delle problematiche emerse con specifico riferimento al tema della forma di governo regionale dopo la riforma dell'elezione diretta del Presidente di Regione introdotta con la legge costituzionale n. 1 del 1999. In particolare ci si è soffermati sull'ampia e importante giurisprudenza costituzionale, per poi verificare come, proprio sulla base di quella giurisprudenza, i diversi Statuti regionali abbiano recepito i principi della citata riforma costituzionale. Da ultimo l'Autore ha analizzato lo Statuto della Regione Emilia- Romagna, con specifico riferimento alla forma di governo, per verificare come e in quale misura quella Regione si fosse discostata dalle conclusioni della Corte costituzionale, dando inoltre conto e analizzando alcune situazioni particolari e problematiche che si sono verificate nella stessa Region
Ionic Liquid for High Energy Supercapacitors
No full textHybrid and asymmetric supercapacitors in ionic liquids for high power applications in transportation
Forme alternative di risoluzione delle controversie con la pubblica amministrazione ed effettività della tutela
No full textMethanol oxidation by pEDOT-pSS/PtRu in DMFC
No full textDirect methanol fuel cells (DMFCs) are attracting more and more attention because of their operating temperature and easy fuel management. While carbons are the most widely used supports for both metal catalysts, i.e. PtRu for methanol oxidation and Pt for oxygen reduction, conducting polymers also can act as suitable supports for catalyst particles because of their conductive and stable three-dimensional structure. We thus chemically synthesized poly3,4-ethylenedioxythiophene-polystyrene-4-sulfonate (pEDOT-pSS) with different (3,4-ethylenedioxythiophene):styrene-4-sulfonate (EDOT:SS) molar ratios and prepared the electrocatalytic systems pEDOT-pSS/PtRu and pEDOT-pSS/Pt, the former by both electrochemical and chemical deposition of PtRu and the latter by chemical deposition of Pt. The results of the electrocatalytic activity tests of the pEDOT-pSS/PtRu composite electrodes performed in 0.1 M H2SO4 - 0.5 M CH3OH liquid solution and in passive, air-breathing DMFC configuration with Nafion 115 protonic membrane and 1 M CH3OH are reported and discussed.
doi: 10.1016/j.jpowsour.2007.09.03
Oligothiophene-S,S-dioxides: A new class of thiophene-based materials
No full textWe report here that bissilylated oligothiophenes may be selectively oxidized at the thienyl sulfurs by m-chloroperbenzoic acid (m-CPBA) to afford stable S,S-dioxides having alternate aromatic and nonaromatic moieties. These compounds are characterized by enhanced electron delocalization, smaller optical gap, and greater electron affinity than the “fully aromatic” precursors
Batterie convenzionali ed avanzate, sistemi efficienti di accumulo e conversione dell'energia
No full textIl sistema energetico di oggi basato principalmente sull’energia da combustibili fossili non è più sostenibile per i previsti danni ambientali, per gli aumenti dei costi dovuti alla crescita della richiesta ed il calo delle risorse e per la dipendenza economica dai Paesi produttori di petrolio, destinato per il 30% alla quasi totalità (90%) del trasporto con macchine a combustione interna a bassa efficienza energetica.
A livello internazionale vi è un crescente impegno per un nuovo piano energetico sostenibile che vede anche aumentare gli investimenti per lo sfruttamento di energia da fonti rinnovabili, in particolare per le tecnologie più mature come quelle eolica e solare, ed è proprio in tale ambito che emerge il ruolo chiave dei sistemi elettrochimici per un uso efficiente dell’energia [1]. Infatti tali fonti rinnovabili hanno carattere di intermittenza, pertanto risultano di fondamentale importanza i sistemi elettrochimici di accumulo e conversione ad alto rendimento energetico, quali batterie ricaricabili e supercapacitori che accumulano l’energia per poi erogarla e distribuirla efficientemente in base alle richieste e alla potenza desiderata
Strategies for high performance supercapacitors for HEV
No full textOur paper highlights the role of supercapacitors in hybrid electric vehicles (HEVs), the current response to the world-wide demand for a clean and low fuel-consuming transport. The main strategies for increasing the specific energy of supercapacitors, which are electrochemical energy storage/conversion systems of high specific power, are discussed, with the focus on electrode material, electrolyte and electrode/electrolyte interface properties. Particular emphasis is given to the use of ionic liquids (IL), which are attracting much attention as green and solvent-free electrolytes, and to the development of high-voltage, IL-based hybrid supercapacitor with high surface area carbon negative electrode and poly(3-methylthiophene) positive. Based on the results of laboratory cells featuring N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonylimide) ILs, the specific energies of hybrid supercapacitor modules are evaluated and compared to those expected for double-layer carbon supercapacitors displaying the same ILs
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