Nitridation of Lithium Silicate Phosphate Glasses for Application as Solid Electrolyte : A Material Properties Study

Abstract: The pursuit of sustainable and high-performance materials is of utmost significance in driving the progress of battery technologies. Solid-state technology represents a promising avenue for the development of batteries with improved sustainability and performance. In this context, the present study delves into the examination of composition and the substitution of oxygen with nitrogen within the 50Li2O-xSiO2-(50-x)P2O5 glass system, specifically as applied to Solid-State electrolytes. The objective is to evaluate the influence of these factors on the electrical properties of the glass and their potential implications for Solid-State battery technology. The glass matrix was obtained through the melt-quenching technique, followed by comprehensive characterization using electrochemical impedance spectroscopy. The influence of varying silica content on the conductivity of the glass was investigated. This led to the selection of the glass system with the highest conductivity for further experiments involving nitridation. Subsequent experiments on nitridation aimed to explore the impact of nitrogen incorporation on the conductivity of the glass. By systematically varying the nitrogen content at different temperatures, the study sought to elucidate the relationship between nitrogen content and the resulting increase in glass conductivity.    The study reveals a noteworthy finding regarding the impact of nitrogen content on the conductivity of the glass. Specifically, when the nitrogen content was increased, the conductivity increased. In the case of a similar glass composition in pellet form, the conductivity at room temperature increased from Log σ = -8,009 (for glass without nitrogen) to Log σ = -6,951 (for nitrided glass). Additionally, the introduction of nitrogen into the glass resulted in a decrease in activation energy, being reduced from 0,66 eV (for oxide glass) to 0,60 eV (for oxynitride glass). These results indicate a clear correlation between increased nitrogen content and enhanced electrical properties of the investigated glasses; although obtaining a homogeneous bulk glass after nitridation was not feasible. Therefore, the nitrided samples were pelletized and sintered under different thermal conditions to obtain characterizable samples. The findings suggest that nitrogen substitution could be a promising approach for enhancing the electrical properties of the glasses of the title system of composition. Further investigation is required to optimize the process and achieve homogeneous bulk oxynitride glass.