Effect of tungsten metal-oxide addition on physical, structural, and electrical properties of borophosphate glasses

Abstract

Demand for electrical energy storage (EES) is growing, necessitating the development of improved batteries. Inorganic glassy materials are a class of essential electrodes due of their excellent conductivity and stable structures, they are appropriate for both cathode and anode applications. The most important characteristics that determine the dynamic behavior and rate performance of batteries are the ionic and electronic conductivities of active materials. In this sense, many crystalline, vitreous, and glass ceramics are investigated for their electrical properties. To create uniformly mixed glasses within the xLi2WO4–(50–x)Li2O–40P2O5–10B2O3 system, the melt-quenching technique is employed. Glasses containing up to 50 mol% Li2WO4 are synthesized with a substantial region of glass formation. They are homogeneous, transparent, and bubble-free. The structural approach and selected physical parameters of these glasses, such as density, molar volume, electrical conductivity, and glass transition temperature, are evaluated. The study emphasizes that an increase in the Li2WO4 amount leads to an elevation in both the density (ρ) and molar volume (Vm). Infrared spectroscopy identifies the presence of numerous structural units within the glass framework. Electrical conductivity measurements of the glasses are investigated using impedance spectroscopy. The measurements are taken over a wide frequency range of 10 Hz to 1 MHz and across temperatures ranging from 303K to 403K. It is highlighted that the electric conductivity rises as the Li2WO4 content is added. The glass with x = 30 mol% exhibits a dc conductivity of 8.63 × 10−7 (Ω−1 cm−1) at room temperature and 8.90 × 10−5 (Ω−1 cm−1) at 150°C. To gain insight into the conductivity relaxation mechanism, the frequency dependence of the glasses' conductivity is investigated. The results indicate that the ion transport in the glasses is governed by the correlated barrier hopping mechanism, which follows Jonscher's power behavior. The scaling conductivity spectra reveal that the conduction mechanism in the glasses is influenced by both temperature and composition.