Investigation of Na-ion battery applicability and supercapacitance properties of ZrCr<sub>2</sub> alloyed with Na: a first-principles study.

Abstract

Here, the [Formula: see text] compound has been investigated as a novel candidate material for supercapacitor electrodes. Moreover, its alloy with Na in replacement of Cr atoms ([Formula: see text]) has been structured in order to prove Na-ion battery applicability and supercapacitance behavior as a hybrid energy material. The density functional theory with the general gradient approximation has been used for the present work calculations. The structural, thermodynamic, and dynamic stability of the compounds have been tested using the cohesive energy, enthalpy of formation energy, and phonon calculation, respectively. The diffusion coefficient for the [Formula: see text] is 9 × 10[Formula: see text] [Formula: see text]/s which shows an improvement of 1× 10[Formula: see text] [Formula: see text]/s in compare with the pure compound. While its largest value at 300 K for electrical conductivity per relaxation time is 2.64 × 10[Formula: see text] and lower than that for [Formula: see text]. Furthermore, the largest peaks of areal quantum capacitance are 511.06 μF/[Formula: see text] (at 1.41 V) and 414.03 μF/[Formula: see text] (at - 0.63 V) for [Formula: see text] and [Formula: see text], respectively. These results introduce new candidates for supercapacitance and Na-ion battery industries.