First-principles study of the effect of O and S functional groups on the lithium storage properties of Zr2N materials

Abstract

This paper constructs a single O and S functionalized Zr₂N model for surface levelling and at the same time a series of bifunctional models with different functional group ratios and distributions. The influence of these functional groups on the electrochemical and lithium storage properties of Zr₂N materials has been systematically investigated in terms of lithium atom adsorption, migration and lithium storage capacity. Among them, the theoretical lithium storage capacities of Zr₂NO₂ and Zr₂NS₂ with a low migration barrier are more than 755.02 and 678.30 mA h g⁻¹, respectively. The results show that the O and S-functionalized Zr₂N materials are all metallic and capable of adsorbing a certain number of lithium atoms. By controlling the ratio and distribution of the O and S functional groups, the adsorption position and adsorption energy of the lithium atoms can be influenced to a certain extent. Especially, the aim of improving the lithium storage performance of the material can be achieved in this way.