Synthesis and characterization of Li2O K2O CuS modified sodium phosphate glasses

Abstract

Lots of research has been carried out to develop oxide/sulfide glasses as solid electrolytes for batteries applications. The ionic conductivity of the glasses is generally higher than that of the corresponding crystalline counter part because of their open structure. Sulfide based glasses show an increase in ionic conductivity more than three orders of magnitude as compared to the oxide glasses of the similar composition. However, sulfide based glasses are hygroscopic in nature. So, reaction with environmental moisture leads to generation of H2S gas. Addition of oxides in the sulfide glasses can increase their chemical stability dramatically with marginal decrease in ionic conductivity. Mixed anions effect in either oxide or in sulfide based glasses, enhances the ionic conductivity and thermal stability simultaneously. Based on the literature review, different series of glasses were synthesized and studied in detail. Moreover, for binary sodium-phosphate glass-ceramics, mechanical properties and their relationship with structural changes are discussed. The effect of modifiers (Li2O/K2O/CuS) on thermal stability and on crystallization kinetics in the sodium-phosphate glasses is also presented in this thesis. The entire work of the thesis is presented in five chapters as follows: First chapter deals with the general introduction of the glasses and their synthesis by different routes. Different theories for glass formation and different class of fast ion-conducting glasses as solid electrolytes for batteries applications are also described. Mixed anions effect on stability and on overall conductivity is discussed in detail. Second chapter is related to the literature review of sulfide and oxide glasses, their synthesis and properties. Synthesis and characterization of oxy-sulfide based glasses for better stability in air are discussed. Mixed modifiers effect on thermal stability and crystallization are also described in this chapter.