Engineering of cathode materials for sodium-ion batteries

Abstract

The continuously increasing worldwide demand for cost-efficient, eco-friendly, and sustainable energy storage devices has driven the search beyond traditional lithium-ion batteries. Among several energy storage systems, sodium-ion batteries have become a potential candidate due to the natural availability, abundant supply, and affordable nature of sodium resources, together with similar electrochemistry to lithium-ion batteries. Though these have the advantages listed, sodium-ion batteries are hindered by critical issues due to the larger ionic radius and increased molar mass of Na+ ion, leading to phase instability, slow diffusion kinetics, and lower energy density. Here, the cathode material is the most critical ingredient as it determines the overall capacity, operating voltage, energy density, and cycle life performance of the battery. The current thesis is dedicated to engineering, optimization, and thorough assessment of several cathode materials for sodium-ion batteries through tailoring structure, substituting elements, and defect engineering.