1,721,011 research outputs found
Ricerca e sviluppo di materiali e processi per la realizzazione di materiali anodici con prestazioni migliorate. Test elettrochimici su nanotubi di TiO2 ottenuti mediante ossidazione di un substrato in titanio
No full textIl presente rapporto descrive la caratterizzazione elettrochimica di anodi costituiti da nanotubi di ossido di titanio (TiO2) ottenuti mediante ossidazione di un substrato in titanio. Gli anodi sono stati investigati in semicelle Li/elettrolita liquido/TiO2 in termini di capacità, cicli di vita ed efficienza coulombica a differenti regimi di corrente
Investigation of swelling phenomena in PEO-based polymer electrolytes: II. Chemical and electrochemical characterization
No full textRicerca e sviluppo di materiali e processi per la realizzazione di materiali anodici con prestazioni migliorate. Test elettrochimici su anodi compositi
No full textIl presente rapporto descrive la preparazione e la caratterizzazione elettrochimica di anodi che utilizzano TiO2 (ossido di titanio), in qualità di materiale attivo. L’ossido di titanio, preparato per via elettrochimica è stato confrontato con TiO2 preparato sia mediante tecnica laser (ENEA) che commerciale
Plastic power sources
No full textLithium ion polymer batteries and laminated solid-state redox supercapacitors, formed by placing a highly conducting gel-type membrane electrolyte between a graphite film and a composite cathode film and between a poly(pyrrole)–poly(aniline) electrode combination, respectively, have been fabricated and tested. The preliminary results are encouraging in suggesting that these plastic power sources may be particularly advantageous for mobile electronic products and for zero emission electric vehicles
Sintesi, purificazione e caratterizzazione chimico-fisica dei liquidi ionici PYR13TFSI e PYR13IM14
Full text linkIl presente rapporto tecnico descrive sintesi, purificazione e caratterizzazione di due liquidi ionici, aventi interesse come componenti elettrolitici per batterie al litio e composti dallo stesso catione Nmetil-N-propilpirrolidinio (PYR13)+, ma differente anione (rispettivamente bis(trifluorometilsulfonil) immide, TFSI-, e (nonafluorobutilsulfonil)immide, IM14-). I liquidi ionici PYR13TFSI e PYR13IM14 sono stati sintetizzati seguendo un protocollo (estendibile a qualunque liquido ionico idrofobico) che impiega solamente acqua come unico solvente, rappresentando un notevole miglioramento in termini di impatto ambientale rispetto agli attuali processi sia in scala di laboratorio che industriale. Particolare cura è stata prestata al processo di purificazione. L’analisi NMR ha confermato l’identità del catione dei liquidi ionici, validandone il metodo di sintesi. La purezza dei liquidi ionici è stata controllata mediante spettrofotometria UV-Vis e fluorescenza a raggi X mentre il contenuto di umidità è stato determinato mediante titolazione coulombmetrica. Le proprietà termiche sono state studiate mediante calorimetria differenziale a scansione e analisi termogravimetrica. Le proprietà chimico-fisiche sono state investigate in termini di densità e conducibilità ionica specifica. Tutte le caratteristiche dei liquidi ionici, in funzione di una loro applicazione quali solventi per elettroliti in batterie al litio, sono state valutate in funzione della natura dell’anione. I risultati ottenuti sono discussi nel presente rapporto tecnico.The present technical report describes synthesis, purification and characterization of two ionic liquids of interest as lithium battery electrolyte components and composed of the same cation (PYR13)+ but different anions (TFSI- and IM14-). Ionic liquids were synthesized following a protocol that uses onlywater as the processing solvent, allowing for an improvement in terms of environmental impact over current processes. Particular care has been given to the purification processe. NMR analysis confirmed the identity of the cation, validating the synthesis method. The purity of the ionic liquids was controlled
by UV-Vis spectrophotometry and X-ray fluorescence while the moisture content was determined by coulombmetric titration. The thermal properties were investigated by differential scanning calorimetry and thermogravimetric calorimetry whereas the physicochemical ones were studied in terms of density and specific ionic conductivity. The characteristics of the ionic liquids have been found to depend on the nature of the anion, especially the melting point and ion transport properties. The obtained results are discussed in this internship report
Outstanding compatibility of hard-carbon anodes for sodium-ion batteries in ionic liquid electrolytes
No full text: Hard carbons (HC) from natural bio-waste have been investigated as anodes for sodium-ion batteries in electrolytes based on the 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI) and N-trimethyl-N-butylammonium bis(fluorosulfonyl)imide (N1114FSI) ionic liquids. The Na+ intercalation process has been analyzed by cyclic voltammetry tests, performed at different scan rates for hundreds of cycles, in combination with impedance spectroscopy measurements to decouple bulk and interfacial resistances of the cells. The Na+ diffusion coefficient in the HC host has been also evaluated via the Randles-Sevcik equation. Battery performance of HC anodes in the ionic liquid electrolytes has been evaluated in galvanostatic charge/discharge cycles at room temperature. The evolution of the SEI (Solid Electrochemical Interface) layer grown on the HC surface has been carried out by Raman spectroscopy. Overall the sodiation process of the HC host is highly reversible and reproducible. In particular, a capacity retention exceeding 98 % of the initial value has been recorded in N1114FSI electrolytes after more than 1500 cycles with a coulombic efficiency above 99 %, largely beyond standard carbonate-based electrolytes. Raman, transport properties and impedance confirms that ILs disclose the formation of SEI layers with superior ability to support the reversible Na+ intercalation with the possible minor contributions from the EMI+ cation
Realizzazione e prova di celle complete da laboratorio. Test elettrochimici di miscele elettrolitiche miste in semicelle e celle complete
No full textIl presente rapporto descrive la caratterizzazione di miscele elettrolitiche miste, sviluppate nell’ambito dell’Accordo di Programma ENEA-MSE per celle litio-ione destinate ad applicazioni alle reti elettriche, in semicelle catodiche e anodiche. Queste ultime sono state realizzate utilizzando gli elettrodi costituiti dai materiali attivi LiFePO4 e TiO2, selezionati nel corso delle attività svolt
A Study of the Conformers of the (Nonafluorobutanesulfonyl)imide Ion by Means of Infrared Spectroscopy and Density Functional Theory (DFT) Calculations
Full text linkPyrrolidinium-based ionic liquids with anions of the per(fluoroalkylsulfonyl)imide family
are particularly interesting for their use as electrolytes in lithium batteries. These ions have several
geometric isomers and the presence of different ion conformers and their distribution affects the ILs
(Ionic liquids) physical and chemical properties. In the present work, we report the temperature
dependence of the infrared spectra of the N-butyl-N-methyl-pyrrolidinium(trifluoromethanesulfonyl)
(nonafluorobutanesulfonyl)imide (PYR14-IM14) ionic liquid; DFT (Density Functional Theory)
calculations performed with different models provides indications about the IM14 conformers and
their vibrational spectra. Moreover the temperature dependence of the intensity of the lines identified
as markers of different conformers provide indications about the conformers’ distribution and the
difference of their enthalpy in the liquid phase
Sodium-conducting ionic liquid-based electrolytes
No full textMixtures, based on the N-butyl-N-methylpyrrolidinium bis(trifluoroMethanesulfonyl)imide (PYR14TFSI) ionic liquid and the NaTESI salt, as low flammability and volatility electrolytes for safer sodium electrochemical energy storage devices, were prepared and investigated in terms of thermal and ion-transport properties. The PYR14TFSI-NaTFSI electrolytes showed melting point down to 30 C. No difference in terms of ion-transport properties was observed with respect to analogous lithium electrolyte systems. Conductivity values above 1 x 10(-3) S cm(-1) were observed at room temperature. (C) 2014 Elsevier B.V. All rights reserved
Pulsed Electrosynthesis of Polypyrrole in N-Butyl-N-Methyl- Pyrrolidinium Bis(Trifluoromethanesulfonyl)Imide Ionic Liquid for Electrochemical Sensors
No full textPolypyrrole (pPy) thin films were synthesized electrochemically by a pulse method on platinum electrodes in N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR14TFSI). The pulse deposition method allowed the synthesis of well adherent pPy layers on Pt that are attractive for the realization of sensors and biosensors because of their good selectivity with respect to the most common interferents. The EIS (Electrochemical Impedance Spectroscopy) response to hydrogen peroxide and biological interferents indicated pPy as a highly sensitive electrochemical platform for the impedimetric sensing of H2O2. The polymer was overoxidated (opPy) before the characterization to prevent its electrochemical contribution when working in aqueous solution. opPy was then functionalized by glucose oxidase enzyme and the device so assembled was tested as a impedimetric biosensor. This technique showed to have great chances to substitute classic detection methods
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