Emerging Surface Engineering Methods for Lithium Metal Anodes: Critical Review Beyond Conventional SEI and Surface Coatings

Abstract For rechargeable lithium batteries with high energy density, lithium metal anode is an ideal candidate due to its high theoretical capacity (3860 mAh g⁻¹) and low electrode potential (−3.04 V versus standard hydrogen electrode). Despite its promising characteristics, it faces formidable obstacles such as dendritic growth and poor formation of solid electrolyte interphase (SEI) layers. To overcome such obstacles, multifaceted unconventional surface engineering approaches are hypothesized, tested, and examined. In this review, in addition to the conventional SEI and surface coatings, the principles and recent progress of the unconventional surface engineering methods are summarized and assessed, based on the interfacial thermodynamics and factors governing the interface between the electrode and the electrolyte. It connects and provides the newest insight on material science, design methodologies, and fabrication techniques, which require significant attention. This review reveals the significance of unconventional methods in enhancing both electrochemical performance and safety of the next‐generation lithium metal batteries, providing a comprehensive understanding of the current research landscape and roadmaps for future technological breakthroughs.