High Electronically Conductive Tungsten Phosphate Glass-Ceramics.

Sanja Renka,Petr Kalenda,Petr Mošner,Andrea Moguš-Milanković,Ana Šantić,Teodoro Klaser,Sanja Burazer

doi:10.3390/nano10122515

Sanja Renka, Petr Kalenda + Show 5 more

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https://doi.org/10.3390/nano10122515

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Abstract

High electronically conductive tungsten phosphate glass-ceramics have been prepared by the controlled crystallization of binary 60WO3–40P2O5 glass in the temperature range from 700 to 935 °C and for 1 to 24 h. The substantial increase in the conductivity for four orders of magnitude is a result of the formation of electronically conductive W2O3(PO4)2 and WO3 phases. At low crystallization temperature the dominant W2O3(PO4)2 phase is created, whereas at 935 °C for 24 h the formation of semiconducting WO3 crystallites of an average size of 80 nm enhances the conductivity to the highest value of 1.64 × 10−4 (Ω cm)–1 at 30 °C. The course of the crystallization and its impact on this exceptionally high electronic transport of binary tungsten phosphate glass-ceramics has been discussed in detail. Since such highly electronically conductive WO3-based glass-ceramics have a great potential as cathode/anode materials in solid state batteries and as electrocatalysts in fuel cells, it is of interest to provide a novel insight into the improvement of their electrical properties.

Highlights

The interest in glass-ceramics has grown exponentially in the recent years due to the novel and useful physical properties that can be obtained by controlling the crystallization process in the glass
The physical properties of glass-ceramics are strongly dependent on the size, type, morphology, and distribution of crystalline phases inside the glass matrix, all of which can be tuned by changing the crystallization conditions
According to the DTA results reported in the previous papers [29,30,33] the temperatures of heat treatments of binary 60WO3-40P2O5 glass were chosen to be in the temperature region above glass transition temperature (Tg = 520 ◦C) at 700 ◦C and 800 ◦C for 1 and 6 h and at crystallization temperature Tc = 935 ◦C for 1, 12 and 24 h

Summary

Introduction

The interest in glass-ceramics has grown exponentially in the recent years due to the novel and useful physical properties that can be obtained by controlling the crystallization process in the glass. The crystallization processes were induced by heat-treatments at different temperatures and times which enabled us to prepare glass-ceramics with various amounts of crystalline phases and comprehensively examine their role in electrical transport.

Results

Conclusion