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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Optimizacija i karakterizacija elektrolita na bazi jonskih tečnosti pogodnih za litijum jonske baterije / Optimization and characterization of ionic liquid based electrolytes for Li-ion batteries

Zec Nebojša 08 November 2017 (has links)
<p>U ovoj doktorskoj disertaciji ispitivani su elektroliti na bazi jonskih tečnosti pogodni za<br />primenu u litijum&nbsp; jonskim baterijama. Fizičko-hemijska svojstva binarnih sme&scaron;a<br />jonskih tečnosti sa dicijanamidnim i bis(trifluorometilsulfonil)imidnim anjonima i<br />molekulskih rastvarača ispitana su u celom opsegu molskih udela i na različitim<br />temperaturama. Na osnovu izmerenih gustina, viskoznosti i električne provodljivosti<br />izračunati su različiti fizičko hemijski parametri i diskutavne interakcije između komponenata sme&scaron;a. Ispitana je termička i elektrohemijska stabilnost odabranih<br />elektrolita. Dodatkom litijumove soli u odabrane binarne sme&scaron;e dobijeni su ternarni<br />sistemi koji su okarakterisani u zavisnoti od koncentracije litijumove soli. Odabrani<br />elektroliti upotrebljeni su za&nbsp; ispitivanje performansi litijum&nbsp; jonske ćelije sa anatas<br />TiO2&nbsp; nanotubularnim elektrodama.Cikličnom voltametrijom i galvanostatskim<br />cikliranjem su ispitane performanse ćelije u toku 150 ciklusa punjenja i pražnjenja. Na<br />osnovu ciklovoltametrijskih merenja izračunati su koeficijenti difuzije i energija aktivacije za difuziju.</p> / <p>In this doctoral dissertation, Ion liquid-based electrolytes were tested for use in&nbsp; lithium-ion batteries. The physicochemical properties of binary mixtures of ionic&nbsp; liquids with dicyanamide and bis (trifluoromethylsulfonyl) imide anions and&nbsp; molecular solvents were examined throughout the range of molar proportions and at different temperatures. Based on the measured densities, viscosity and electrical conductivity, various physical chemical parameters and discrete interactions between&nbsp; the components of the mixture are calculated. Thermal and electrochemical stability of selected electrolytes was examined. By addition of lithium salt to the selected binary mixtures, ternary systems were characterized which were characterized by the concentration of lithium salt. The selected electrolytes were used to test the performance of the lithium-ion cell with anatomic TiO2 nanotubular electrodes. Cyclic voltammetry and galvanostatic cycling tested the cell&#39;s performance during the 150 charge and discharge&nbsp; cycles. Based on cyclotoltametric&nbsp; measurements, the diffusion coefficients and activation energies for diffusion were calculated.</p>
2

Fizičko-hemijska karakterizacija binarnih smeša jonskih tečnosti i laktona i njihova primena kao elektrolita za litijum-jonske baterije / Physicochemical characterisation of ionic liquids and lactones binary mixtures and their application as electrolytes for lithium-ion batteries

Papović Snežana 20 July 2018 (has links)
<p>U&nbsp; ovoj&nbsp; doktorskoj&nbsp; disertaciji&nbsp; ispitivani&nbsp; su&nbsp; elektroliti&nbsp; na&nbsp; bazi binarnih&nbsp; sme&scaron;a&nbsp; imidazolijumovih&nbsp; jonskih&nbsp; tečnosti&nbsp; i&nbsp; laktona&nbsp; koji su&nbsp; pogodni&nbsp; za&nbsp; primenu&nbsp; u&nbsp; litijum-jonskim&nbsp; baterijama.&nbsp; Fizičkohemijska&nbsp; svojstva&nbsp; binarnih&nbsp; sme&scaron;a&nbsp; jonskih&nbsp; tečnosti&nbsp; na&nbsp; bazi imidazolijum katjona i <em>bis </em>(trifluorometilsulfonil)imidnog anjona i laktona ispitana su u celom opsegu molskih udela i na različitim temperaturama.&nbsp; Na&nbsp; osnovu&nbsp; izmerenih&nbsp; gustina,&nbsp; viskoznosti&nbsp; i električne&nbsp; provodljivosti&nbsp; izračunati&nbsp; su&nbsp; različiti&nbsp; fizičko-hemijski parametri i diskutovane&nbsp; interakcije između komponenata sme&scaron;a. Ispitana&nbsp; je&nbsp; termička&nbsp; i&nbsp; elektrohemijska&nbsp; stabilnost&nbsp; odabranih elektrolita.&nbsp; Na&nbsp; osnovu&nbsp; dobijenih&nbsp; rezultata,&nbsp; prvo&nbsp; je&nbsp; odabran odgovarajući&nbsp; lakton&nbsp; koji&nbsp; je&nbsp; kasnije&nbsp; kombinovan&nbsp; sa&nbsp; jonskim<br />tečnostima&nbsp; na&nbsp; bazi&nbsp; imidazola,&nbsp; koje&nbsp; se&nbsp; međusobno&nbsp; razlikuju&nbsp; u dužini&nbsp; bočnog&nbsp; niza&nbsp; katjona.&nbsp; Na&nbsp; osnovu&nbsp; fizičko-hemijskih svojstava&nbsp; na&nbsp; različitim&nbsp; temperaturama&nbsp; i&nbsp; pri&nbsp; različitim&nbsp; sastavima binarnih&nbsp; sme&scaron;a&nbsp; diskutovan&nbsp; je&nbsp; način&nbsp; organizacije&nbsp; njihovih<br />komponenata.&nbsp; U&nbsp; binarne&nbsp; sme&scaron;e&nbsp; koje&nbsp; su&nbsp; se&nbsp; pokazale&nbsp; kao najperspektivnije&nbsp; sa&nbsp; stanovi&scaron;ta&nbsp; električne&nbsp; provodljivosti, viskoznosti,&nbsp; elektrohemijske&nbsp; stabilnosti&nbsp; i&nbsp; (ne)zapaljivosti&nbsp; dodata je litijumova so. Tako dobijeni ternarni sistemi su okarakterisani<br />u zavisnosti od koncentracije litijumove soli. Odabrani elektroliti upotrebljeni su za ispitivanje performansi litijum-jonske ćelije sa elektrodama&nbsp; na&nbsp; bazi&nbsp; anatas&nbsp; TiO<sub>2</sub>&nbsp; nanocevi.&nbsp; Cikličnom voltametrijom&nbsp; i&nbsp; galvanostatskim&nbsp; cikliranjem&nbsp; ispitane&nbsp; su<br />performanse ćelije u toku 350 ciklusa punjenja i pražnjenja. Na osnovu&nbsp;&nbsp; ciklovoltametrijskih&nbsp; merenja&nbsp; izračunati&nbsp; su&nbsp; koeficijenti difuzije jona Li<sup>&nbsp; + </sup>i energija aktivacije za difuziju.&nbsp; Kombinacijom jonskih&nbsp; tečnosti&nbsp; i&nbsp; laktona&nbsp; moguće&nbsp; je&nbsp; dobiti&nbsp; elektrolite&nbsp; smanjene viskoznosti,&nbsp; povećane&nbsp; električne&nbsp; provodljivosti,&nbsp; povećane<br />termičke&nbsp; stabilnosti&nbsp; usled&nbsp; međusobnog&nbsp; stabilizacionog&nbsp; efekta laktona na imidazolijumove jonske tečnosti.</p> / <p>In&nbsp; this&nbsp; doctoral&nbsp; dissertation,&nbsp; binary&nbsp; mixtures&nbsp; based&nbsp; on&nbsp; imidazolium&nbsp; ionic&nbsp; liquids&nbsp; with&nbsp; lactones&nbsp; were&nbsp; tested&nbsp; for&nbsp; use&nbsp; in lithium-ion&nbsp; batteries.&nbsp; The&nbsp; physicochemical&nbsp; properties&nbsp; of&nbsp; binary&nbsp; mixtures&nbsp; of&nbsp; imidazolium&nbsp; based&nbsp; ionic&nbsp; liquids&nbsp; with&nbsp;<em> bis </em>(trifluoromethylsulfonyl)imide&nbsp; anions&nbsp; and&nbsp; lactones&nbsp; were&nbsp; examined&nbsp; throughout&nbsp; the&nbsp; whole&nbsp; composition&nbsp; range&nbsp; and&nbsp; at&nbsp; different temperatures. Based on the measured densities, viscosity&nbsp; and electrical conductivity, various physical chemical parameters&nbsp; and discrete interactions between the components of the mixture are&nbsp; calculated.&nbsp; Thermal&nbsp; and&nbsp; electrochemical&nbsp; stability&nbsp; of&nbsp; selected&nbsp; binary&nbsp; mixtures&nbsp; were&nbsp; examined.&nbsp; Based&nbsp; on&nbsp; obtained&nbsp; results&nbsp; was&nbsp; selected lactone&nbsp; which is later combined with imidazolium based&nbsp; ionic liquid,&nbsp; differing from each other in the length of the cation. Based&nbsp; on&nbsp; the&nbsp; physico-chemical&nbsp; properties&nbsp; at&nbsp; different&nbsp; temperatures and in the different compositions of binary mixtures, the way of organizing their components is discussed. Lithium salt&nbsp; is added to the binary mixtures that have been shown as the most perspective&nbsp; from&nbsp; the&nbsp; standpoint&nbsp; of&nbsp; electrical&nbsp; conductivity, viscosity,&nbsp; electrochemical&nbsp; stability&nbsp; and&nbsp; (non)flammability.&nbsp; The&nbsp; resulting&nbsp; ternary&nbsp; systems&nbsp; are&nbsp; characterized&nbsp; according&nbsp; to&nbsp; the concentration of lithium salt.&nbsp; The selected electrolytes were used to test the performance of the lithium-ion cell with anatase TiO<sub>2</sub> nanotubular&nbsp; electrodes.&nbsp; Cyclic&nbsp; voltammetry&nbsp; and&nbsp; galvanostatic&nbsp; cycling&nbsp; tested&nbsp; the&nbsp; cell&#39;s&nbsp; performance&nbsp; during&nbsp; the&nbsp; 350&nbsp; charge&nbsp; and discharge&nbsp; cycles.&nbsp; Based&nbsp; on&nbsp; cyclic&nbsp; voltammetric&nbsp; measurements, the&nbsp; Li <sup>+</sup> ion&nbsp; diffusion&nbsp; coefficients&nbsp; and&nbsp; activation&nbsp; energies&nbsp; for diffusion&nbsp; were&nbsp; calculated.&nbsp; Combination&nbsp; ionic&nbsp; liquid&nbsp; and&nbsp; lactone could&nbsp; be&nbsp; obtained&nbsp; electrolytes&nbsp; with&nbsp; lower&nbsp; viscosity,&nbsp; higher electrical&nbsp; conductivity,&nbsp; improved&nbsp; thermal&nbsp; stability&nbsp; due&nbsp; to stabilization effect of lactone on imidazolium based ionic liquids.</p>

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