LAUSR

Production of energy and its storage has become the main concern at the present time. Global environmental issues and the rising demand for a powering system of portable electronic devices as well as zero gaseous emission vehicles triggers research towards high energy and high voltage systems. Although Li‐ion batteries have conquered the portable electronic market, yet its limited availability, high cost and safety issues have led to the search its alternatives. Na‐ion and K‐ion batteries may turn out to be a promising candidate for storage devices as they are cheaper and have higher energy density as compared to Li metals. We have proposed a fundamental theoretical design based on cubic double antiperovskite structure X6SOA2 (X = Na, K; A = Cl, Br and I) by full‐potential augmented plane wave (FP‐LAPW) method as implemented in the WIEN2k code within the density functional theory (DFT). We have calculated structural, electronic, optical, elastic, and thermodynamic properties and may be concluded that these materials are mechanically, dynamically, and thermally stable and have profound characteristics in high UV energy range. As these double antiperovskites have been studied for the very first time, this study may unfold a new vista for more comprehensive experimental and theoretical investigations for the search for non‐toxic, eco‐friendly and cheaper energy storage devices.