First-principles study on electronic properties and lattice configurations of Ni3S2/LiAlO2 interface towards lithium ions storage

Abstract

Construction surface coating is an effective and widely adopted approach to improve coulomb efficiency and cycle stability of transition metal sulfides. For example, LiAlO2 coated Ni3S2 (LiAlO2@Ni3S2) shows significantly improved cycle stability of the Li-ion battery. However, the coating effects of LiAlO2 on electrochemical performance of Ni3S2 are still unclear. In this study, the local structure, electrical properties, and work functions of Ni3S2(110)/LiAlO2(101) interface were studied by density functional theory (DFT) method to reveal the effects of LiAlO2 coating on electrochemical performance of Ni3S2 at the micro level. The results show that the Ni3S2 (110)/LiAlO2(101) interface has a small lattice mismatch of 4.02%, which bonds to each other through the formation of NiO chemical bonds, and exhibit lower interface formation energy that can predict the stability of the interface. The work function shows that the coating of LiAlO2 is beneficial to the transportation of Li+. The results provide a theoretical reference for design of appropriate coating layer to improve coulomb efficiency and cycle stability of transition metal sulfide in lithium ions batteries.