First-principles calculations of bulk WX2(X = Se, Te) as anode materials for Na ion battery.

ABSTRACT

Two-dimensional transition metal dichalcogenides are promising anode materials for Na ion batteries (NIBs). In this study, we carried out a comprehensive investigation to analyze the structural, electrochemical characteristics, and diffusion kinetics of bulk WX2(X = Se, Te) by employing first-principles calculation in the framework of density functional theory. We deeply studied the full intercalation of Na+in WX2and diagnosed NayX phase through conversion reaction mechanism. The voltage range of 2.05-0.48 V vs Na/Na+for NayWSe2and 2.26-0.65 V for NayWTe2(y= 0-3) have been noted. Density of states analysis showed metallic behavior of WX2(X = Se, Te) during sodiation. The facile pathways for Na+mobility through WX2have shown that tungsten dichalcogenides are inferred as excellent electrode material for NIBs.