Mixed alkali effect in lithium-sodium phosphate glasses modified with tungsten oxide

Result code in IS VaVaI

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Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Mixed alkali effect in lithium-sodium phosphate glasses modified with tungsten oxide

Original language description

Lithium and sodium phosphates belong to materials studied as solid electrolytes for batteries. Their modification with other oxides can be due to the optimization of electrical properties or chemical durability thermal stability etc. This contribution is devoted to the study of lithium-sodium tungsten-phosphate glasses of the composition xLi2O-(40-x)Na2O-30P2O5-30WO3 with x = 0, 10, 20, 30 a 40 mol% Li2O. Basic parameters of the glasses were determined (density, molar volume, chemical durability) and their thermal behavior was studied by differential thermal analysis, dilatometry and hot-stage microscopy. Temperature dependence of glass transition temperature reveals a minimum at x = 20 mol% Li2O, characteristic for the mixed-alkali effect, whereas the thermal expansion coefficient decreases monotonously from 19.9 to 13.1 ppm/K. The replacement of sodium cations by lithium cations results in a lower ionicity of W-O bonds, which is reflected by the shift of band of W-O vibrations from 941 to 954 cm-1. Electrical and dielectric properties were measured within the range of 106 Hz to 0,01 Hz and the temperature range 303-513 K. From the obtained dependences of D.C. electrical conductivity on temperature, the activation energy was calculated using Arrhenius equation. Activation energy reaches a maximum at the glass with 20 mol% Li2O, whereas electrical conductivity reveals a minimum at the same composition. The observed nonmonotonous behavior of electrical conductivity and its activation energy is characteristic for the mixed-alkali effect observed previously also in other phosphate glasses.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

10402 - Inorganic and nuclear chemistry

Project

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Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Proceedings of the 5th International Conference on Chemical Technology

ISBN

978-80-86238-65-4

ISSN

2336-811X

e-ISSN

neuvedeno

Number of pages

6

Pages from-to

278-283

Publisher name

Česká společnost průmyslové chemie

Place of publication

Praha

Event location

Mikulov

Event date

Apr 10, 2017

Type of event by nationality

CST - Celostátní akce

UT code for WoS article

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