Artificial Interphases for Highly Stable Lithium Metal Anode

Lithium (Li) metal anode is highly pursed as the “Holy Grail” electrode because of its extremely high theoretical capacity (3,860 mAh g⁻¹, 10-fold higher than that of commercial graphite anode), low gravimetric density (0.534 g cm⁻³), and the most negative equilibrium potential (−3.045 V versus standard hydrogen electrode). During practical operation, however, the aforementioned merits are largely hidden by the highly unstable electrode-electrolyte interface originating from the intrinsic high reactivity of metallic Li, which directly dictates a low Coulombic efficiency and a widely observed lithium dendrite formation. Designing an artificial interface with various in situ and ex situ methods is employed as an emerging strategy to greatly alter the surface chemistry of Li metal anode, hence intuitively enhancing the interfacial compatibility toward the electrolyte and enabling a highly stable Li anode in working batteries. In this review, the recent efforts on strengthening the Li metal and liquid/solid-electrolyte interfaces with artificial films are comprehensively summarized and discussed, the significance of interface-related science and engineering in both liquid-state and solid-state Li metal batteries is highlighted, and the future research directions in this field are prospected.