Exploring the electrochemical cation exchange and anion redox in polyanionic

This thesis explores the promising potential of cation exchange and anion redox in battery materials. This research reveals insights with exciting implications for energy storage advancement. The Chapter III highlights the optimization of the Li-by-Na ion exchange process and demonstrates encouraging progress in achieving desired compositions. Comparative study between lithium-ion and sodium-ion systems showcases lithium's superior rate capabilities and diffusion, underscoring the need for improving sodium-ion batteries. Structural evolution during cation exchange processes is crucial, with techniques like XRD and GITT providing invaluable information about mechanisms and stability. The findings contribute to battery research and development, showcasing the potential of cation exchange electrode materials for improved performance and expanded energy storage capabilities. Chapter IV delves into Na2MoS2O2 as a cathode material for sodium-ion batteries. Comprehensive techniques like FTIR, XPS, and in-situ electrochemical-XRD uncover its redox mechanism, stability, and cycling performance. The promising reversibility and stability of Na2MoS2O2 during Na+ extraction and insertion suggest its potential in sodium-ion battery applications. Chapter V extends the exploration, detailing the crystal structure evolution and electrochemical performance of Na2MoS2O2 as a lithium storage material. In-situ XRD and electrochemical ion exchange studies illuminate structural changes during charging and discharging, successfully demonstrating cation exchange between Na and Li ions, creating Li3MoS2O2. The assembly of all-solid-state batteries underscores [Li-Na]2MoS2O2's potential as an energy storage material. Together, these chapters contribute to the evolving battery field, offering insights into cation exchange processes, electrode materials optimization, and advanced energy storage technologies.