Local lattice structures and electronic properties of β-Li3PS4/CuS interface

Abstract

In all-solid-state lithium–sulfur batteries (ASSLBs), unfavorable solid–solid contact at the interfaces with sulfide electrolyte (SE) is one of the important reasons affecting the properties of ASSLBs. CuS is a promising cathode material, and [Formula: see text]-Li3PS4 (LPS) is a newly found SE used for ASSLBs. In order to deeply explore the electronic properties at the interface between these two materials, we used the first-principles calculation method to investigate the local lattice structures, electronic properties, work-function, and charge distribution of LPS/CuS interface. The interface binding energy of the LPS/CuS interface is about −0.568 J/m2. Hence, the LPS/CuS interface structure is thermodynamically reasonable and stable with newly formed chemical bonds at the interface. The interfacial electron density of state shows the metallic properties, which are mainly contributed by Cu-[Formula: see text], [Formula: see text] orbitals and S-[Formula: see text], [Formula: see text] orbitals in CuS and S-[Formula: see text] orbital electrons in LPS. Furthermore, the work function of the interface means the formation of a space charge layer, which has a certain influence on the charge and discharging process.