124,999 research outputs found
Lithiated short side chain perfluorinated sulfonic ionomeric membranes: Water content and conductivity
No full textIn view of possible applications as single-ion electrolyte for lithium batteries, some aspects of the lithium form of Hyflon Ion ionomer, a sulfonic short side chain (SSC) electrolyte, have been investigated. The synthesis of the ionomer and the successive membrane preparation is reported. An appropriate methodology for the direct salification of the ionomeric membrane from the SO2F form to lithium salt, using lithium hydroxide in absence of organic solvent has been found. Utilizing these SSC lithium ionomer membranes and though a particular methodology for the dehydration of the lithium ion membrane in non-aqueous media, it has been possible to achieve an ionic conductivity of 10(-3) S cm(-1) at room temperature [W. Navarrini, S. Panero, B. Scrosati, A. Sanguineti, European Patent 1,403,958 A1 (2003)]. Surprisingly it was observed that the membrane ionic conductivity depends on the dehydration methodologies adopted. (C) 2007 Elsevier B.V. All rights reserved
New electrochemical process for in situ preparation of metal electrodes for lithium-ion batteries
No full textA new, in situ experimental procedure, which allows in a single step the formation of a metal, e.g., tin, and its operation as reversible alloying-de-alloying electrode in lithium-ion cells, is here reported. The results demonstrate that this procedure has unique advantages not only in terms of fabrication simplicity but also of electrode response
Recupero e valorizzazione del materiale antropologico del museo Civico di Cuneo:cinque reperti craniali con esiti di lesioni traumatiche..
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Batteria litio-ione polimerica con configurazione innovativa
No full textIl brevetto in oggetto descrive una tipologia di accumulatori innovativi che unisce ragguardevoli prestazioni elettrochimiche a totale sicurezza e compatibilità. Tali batterie impiegano (a) un elettrodo negativo a base di un composito M-C dove M è un metallo (Sn, Sb, Si, Mg, Al) e C è carbone amorfo; (b) un elettrodo positivo a base di un ossido lamellare litiato di nichel e manganese con o senza cobalto; (c) un elettrolita comprendente una membrana gelificata polimerica in cui è racchiusa una soluzione liquida di una sale di litio in una miscela di solventi organici aprotici. L’eventuale addizione di un ritardante di fiamma costituisce un ulteriore passo avanti nella direzione di un’incrementata sicurezza ed una ulteriore innovazione. Il ritardante di fiamma agisce come trappola per i radicali che possono eventualmente formarsi nel corso del processo redox ed iI cui propagarsi è all’origine del fenomeno noto come thermal runaway. I sistemi elettrolitici polimerici che ne derivano sono estremamente stabili chimicamente e non infiammabili per la presenza del ritardante di fiamma. Anche sotto il profilo elettrochimico non sono soggetti a reazioni di decomposizione nella finestra di potenziale di esercizio degli elettrodi prescelti
Recupero e valorizzazione del materiale antropologico del museo civiso di Cuneo: cinque reperti craniali con esiti di lesioni traumatiche.
No full textDispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A process for preparing ionomeric membranes
No full textA process for preparing membranes formed by (per) fluorinated ionomeric electrolytes salified with the lithium ion, comprising the following steps: a) obtaining of (per) fluorinated polymer membranes, containing --SO.sub.2F groups; b) partial or complete salification of (per)fluorinated polymer membranes containing --SO.sub.2F groups with basic lithium compounds and final washing with water; c) swelling and contemporaneous drying process of membranes by dipping in a heterogeneous biphasic system of a dipolar aprotic solvent wherein insoluble solid drying agents are dispersed
Nanotechnology for the progress of lithium batteries R&D
No full textIn this paper we report the strategy followed in our laboratories for the progress of lithium ion batteries. The results show that nanotechnology is a very promising tool for achieving breakthrough in electrode and electrolyte materials. The concept is demonstrated for the cases of metal storage and metal oxide anodes, phospho olivine lithium iron phosphate cathodes and solvent-free, poly(ethylene oxide)-based polymer electrolytes. (C) 2003 Elsevier B.V. All rights reserved
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