The increasing demand for high-energy battery systems has led to investigations for replacing the graphite anode of Li-ion batteries with Li metal due to its high theoretical capacity and high negative potential. The combination of a Li metal anode and a Li-ion cathode can enable high energy density batteries due to a significantly higher specific capacity.,  However, poor cycling performance, low Coulombic efficiency (CE) and the uncontrollable dendrite growth during lithium electrodeposition and electrodissolution still remain as main challenges to be overcome ahead Lithium metal batteries (LMBs) practical application.
One approach to overcome the low performance and the safety issues of LMBs is the development of an artificial SEI (aSEI) to generate a homogeneous Li-ion flux, obtain a protective coating layer that prevents parasitic surface reactions and suppresses the formation of high surface area lithium (HSAL, “lithium dendrites”). In the past, LixM alloy coating layers have shown an improved cycling behavior due to a reduced overpotential and interfacial resistance during lithium electrodeposition. The lithiophilic alloy coating decreases the HSAL formation caused by a high affinity for Li-ion adsorption and a fast lithium diffusion.
Herein we present a new method to generate a LiZn alloy coating on Li metal by using physical vapor deposition (PVD) under vacuum conditions. The lithiophilic coating layer improves the performance of the Li||Li symmetric cell and the full cell by suppressing the formation of HSAL during electrodeposition and electrodissolution. The morphological changes of the Li metal surface were investigated by cryo SEM, Li-EDX and XPS to gain insights of the HSAL growth and the aging process of the LiZn layer.