Niobate-Functional materials for energy storage/conversion applications: Investigation on the dependence of cations incorporation on Nb2O5 solubility, properties, and crystallization behavior

• Applicant: Dr. Maria Rita Cicconi
• Subject Area: Synthesis and Properties of Functional Materials ; Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 524824666

This project aims to design, produce, and characterize a novel class of glasses and glass-ceramics based on niobium with optical/electrical properties that make them suitable for functionalization. Niobium is a versatile element that, in glasses, provides a high refractive index, large non-linear optical susceptibilities, and intense UV absorption while preserving high transparency in the visible region. In the crystallized form, it can stabilize phases having unique properties, such as electro-optical and electro-mechanical coupling, photorefractive, and non-linear optical properties (e.g., LiNbO3, NaNbO3, KNbO3). Furthermore, the (K0.5Na0.5)NbO3 composition is considered crucial in developing environmentally friendly ferroelectrics. Combining the high-temperature stability and optical applications of a pore-free and chemically/mechanically stable aluminosilicate glass matrix with the functional properties of Nb-based crystals dispersed in it would allow an important step forward for developing multi-functional materials (glass-ceramics). These novel glass-ceramics would allow many applications in optics and advanced energy-related technologies, such as second harmonic generation, down- and up-conversion, pyroelectricity, piezoelectricity, and high energy-storage dielectric. To obtain such advanced functionalized materials, it is necessary to understand i) the evolution of the local structure of Nb5+ ions, the distortion of its coordination polyhedra depending on glass polymerization, and the possible interaction with other elements in the amorphous network; and ii) the impact of chemistry/connectivity on crystallization mechanisms and glass-ceramics microstructure. The goal of this project is to answer these critical points, quantify the effect of glass chemistry and Nb2O5 content on the evolution of the Nb5+ structural units, and investigate the influence of cations incorporation on niobate solubility, crystallization behavior, and properties. In addition, we plan to perform advanced characterizations of the developed niobo-aluminosilicates to quantify the functional properties (optical and electric properties) that will establish the potential applications for light management and energy-related applications (energy conversion and energy storage applications).

• DFG Programme: Research Grants