Utjecaj miješanih staklotvoraca na električni prijenos u alkalijskim germano(boro)fosfatnim staklima

doctoral thesis

• Title (english): Effect of mixed glass network formers on the electrical transport in alkali germano(boro)phosphate glasses
• Author: Kristina Sklepić Kerhač
• Mentor: Andrea Moguš-Milanković (mentor)
• Committee member: Višnja Vrdoljak (predsjednik povjerenstva)
• Committee member: Ana Šantić (član povjerenstva)
• Committee member: Marijana Đaković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2020-07-08, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Učinak miješanih staklotvoraca istraživan je u četiri serije Li2O/Na2O–(B2O3)–P2O5–GeO2
stakala. Sustavnom zamjenom jednog staklotvorca, P2O5, drugim, GeO2 pri čemu udio
alkalijskog iona ostaje nepromijenjen, dolazi do promjena u strukturi staklene mreže koje
rezultiraju povećanjem električne provodnosti u svim istraživanim serijama stakala. U
ternarnim je serijama lokalizirana difuzija pokretljivih Li+ i Na+ iona olakšana kontinuiranim
promjenama u fosfatnoj mreži i nastajanjem miješanih germanofosfatnih strukturnih jedinica.
S druge strane, u kvaternim serijama, prisutnost B2O3, uzrokuje bržu depolimerizaciju fosfatne
mreže i umrežavanje s B4 jedinicama zbog čega su pri niskim udjelima GeO2 vrijednosti DC
provodnosti više od odgovarajućih stakala iz ternarne serija. Međutim, pri višim udjelima GeO2
nastaju dodatne miješane jedinice koje utječu na umreženost staklene mreže. Nehomogenosti u
staklenoj mreži stvaraju više zamki za Li+ i Na+ ione zbog čega je porast DC provodnosti slabije
izražen. Također, litijeve serije pokazuju više vrijednosti DC provodnosti u odnosu na
odgovarajuća stakla iz natrijevih serija jer manji ion Li+ može lakše i brže difundirati kroz
staklenu mrežu.

Abstract (english)

The mixed glass network former effect was investigated in four series of Li2O/Na2O–(B2O3)–
P2O5–GeO2 glasses. Systematic replacement of one glass network former, P2O5, by another,
GeO2, while keeping the alkali ion content constant, causes structural modifications of the glass
network, resulting in electrical conductivity enhancement for all four glass series. In ternary
series, localized diffusion of mobile Li+ and Na+ ions is facilitated by continuous changes in the
phosphate network structure and the formation of mixed germanophosphate structural units. On
the other hand, in quaternary series, the presence of B2O3 causes depolymerization of the
phosphate network and cross-linkages with B4 units, which makes the DC conductivity values
higher than those for the corresponding glasses from ternary series at low germanate content.
However, at higher GeO2 content, additional mixed units are formed that affect the connectivity
of the glass network. The inhomogeneities in the glass network create more traps for Li+ and
Na+ ions, which makes the increase in DC conductivity less pronounced. Also, the lithium
glasses show higher values of DC conductivity than the corresponding sodium glasses because
the smaller Li+ ion can diffuse more easily and faster through the glass network.

• Keywords: ionski vodljiva stakla; kruti elektroliti; učinak miješanih staklotvoraca
• Keywords (english): ionicaly conducting glasses; mixed glass network former effect; solid electrolytes
• Language: croatian
• URN:NBN: urn:nbn:hr:217:985387
• Promotion: 2020
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 176 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2022-07-08
• Created on: 2020-07-21 08:35:34