Interfacial properties and Li-ion dynamics between Li3OCl solid electrolyte and Li metal anode for all solid state Li metal batteries from first principles study

Abstract

First-principles calculations and ab initio molecular dynamics (AIMD) methodology are performed to investigate the interfacial properties and ionic transport between Li3OCl solid electrolyte and Li metal anode (LOC/Li). The structural stability, interfacial charge distribution, and electronic properties of the LOC/Li interface are systematically studied to elucidate the basic properties of Li3OCl as a solid electrolyte. The calculated results show that the Li3OCl electrolyte in contact with Li metal is stable, and the interface is almost insulating for electrons. In addition, through AIMD simulations, it is found that the LOC/Li interface is primarily Li-ion conductor. Moreover, the evaluated self-diffusion, conductivity, and activation energy of Li ions in the interface at 300 K are 0.88 × 10−5 cm2/s, 1.60 S/cm, and 0.09 eV, respectively, which are superior to their counterparts in the Li3OCl bulk, indicating that the interface contributes to Li ions transport. Meanwhile, the calculated results show that the Li ions mobilities in the interface are predominantly along the interfacial boundary. Moreover, the Li ionic conductivity in Li3OCl side for LOC/Li interface is one order of magnitude higher than that of bulk Li3OCl due to the effects of the interface and Li metal. The present work provides information on the Li-ion transport in the LOC/Li interface, which will help us to improve the ionic conductivity for future all-solid-state Li metal batteries.