Chalcogen Effects and Cathodic Properties of Scandium-based Materials for Sodium-Ion Batteries

Abstract Sodium-ion batteries emerged as a sustainable alternative to overcome the cost, availability, safety, and energy density concerns challenged by existing commercialized lithium-ion battery technology. This paper focuses on modeling new layered sodium scandium chalcogenides (O, S, and Se) as electrode materials for large-scale energy storage. We examined and compared the structural, electronic, cathodic, and transport properties of NaScX₂ layered materials. The calculated energy barrier for Na-ion diffusion decreases, i.e., 0.7 and 0.57 eV from oxide to selenides. As we go to the higher ionic radii of divalent anions, it shows higher electric polarizability. NaScO₂ has a high theoretical capacity of 268 mAhg⁻¹. Hence, layered selenide has a higher capability to deform the electron charge density of anion by the nearby Na cations. This influences the mobility of diffusing alkali metal cations.