Effect of MoO ₃ content on structural, physical and electrical properties of mixed alkali calcium phosphate glasses for energy storage capacitors

This work was motivated by the limited stability and dielectric performance of phosphate glasses. The main goal is to examine how small MoO₃ additions (0-4 mol%) affect structure, elastic properties, and dielectric response in a mixed-alkali calcium phosphate host. New mixed alkali calcium phosphate with different MoO₃ contents with nominal composition 10K₂O-10Na₂O-(20 - <i>X</i>)CaO-<i>X</i>MoO₃-60P₂O₅ (mole%) glasses (where <i>X</i> = 0, 1, 2, and 4 mol%) were swimmingly prepared <i>via</i> melt quenching. The impact of doping with MoO₃ on the structure, physical and mechanical strength of the prepared glass samples was studied. It is determined that MoO₃/CaO molar ratio substitution led to an increase the density and oxygen packing density (OPD) and a decrease molar volume because the internal structure has changed for the non-crystalline specimens. The calculated mechanical parameters revealed that MoO₃-modified samples have the highest mechanical resistance due to the increased bond strength and structural rigidity. The permittivity of glass samples was measured from 0.1 Hz to 10 MHz at temperatures from 25 °C to 150 °C. The neat glass showed little change in high-frequency permittivity. Adding MoO₃ increased low-frequency permittivity and widened the dispersion range. Two processes appeared: a slow interfacial response at low frequencies and a faster dipolar response at mid-frequencies. The physical, mechanical and electrical data propose that the vitreous materials under study are varied conductors with both electronic and ionic conductivity as suitable for high-performance energy storage capacitor materials. The prepared glass is lead-free and composed of abundant, low-toxicity oxides, aligning with environmentally responsible and sustainable dielectric design.