Protecting Lithium Metal Electrode With Titanium Based Interphase: Synthesis and Battery Performance

Atomic layer deposition (ALD) of interphases is a promising strategy for stabilizing lithium metal negative electrode and mitigating dendrite formation in rechargeable batteries. In this work, we investigate the growth mechanism and electrochemical impact of titanium‐based ALD coatings on highly reactive lithium surfaces. Operando ambient‐pressure X‐ray photoelectron spectroscopy (APXPS) was employed to probe the initial stages of a Ti interphase growth under realistic ALD conditions using TiCl 4 and H 2 O precursors. The first H 2 O pulse rapidly converts the Li surface into LiOH, while subsequent TiCl 4 exposure reacts directly with lithium surface to form a stable LiCl interlayer. TiO x nucleates on this LiCl‐modified surface, resulting in a composite TiO x /LiCl interphase. This synergistic interphase improves electrolyte wettability, promotes uniform Li + flux, and suppresses dendritic growth. Electrochemical evaluation shows that TiO x ‐LiCl‐coated Li anodes deliver substantially enhanced interfacial stability and cycling performance. Symmetric cells exhibit stable operation for over 600 h, while full Li‖LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells with a 10 ALD cycle TiO x /LiCl coating achieve 100% Coulombic efficiency after 300 charge–discharge cycles at 200 mA g −1 , compared with ∼63% for bare lithium. These findings provide mechanistic insight and practical validation of ALD Ti‐based coatings as an effective protection strategy for durable lithium metal batteries.