Anode-free all-solid-state and thin-film batteries: Advances, challenges, and interfacial engineering strategies

Abstract

Anode-free all-solid-state batteries (AFASSBs) have garnered considerable attention as promising next-generation energy storage systems, offering high energy density, enhanced safety, and improved cost efficiency by eliminating the lithium metal anode. However, these advantages are offset by critical challenges, most of which stem from issues at the solid electrolyte–electrode interface. These challenges include interfacial instability, non-uniform lithium deposition during initial charging, and void formation owing to volumetric changes during cycling. Meanwhile, thin-film AFASSBs (TF-AFASSBs), fabricated by implementing the anode-free design in thin-film battery systems, offer distinct advantages over conventional thin-film systems, including higher energy density and a more streamlined cell structure. Moreover, their fabrication using deposition-based approaches promotes better interfacial wettability, thereby enhancing contact between the solid electrolyte and current collector. Despite these advantages, however, TF-AFASSBs are often more susceptible to interfacial degradation and uneven lithium plating than their bulk-type counterparts. In response to these challenges, considerable research has focused on mitigating interfacial and mechanical failures in both AFASSBs and TF-AFASSBs. This review presents an overview of the core characteristics and key limitations of AFASSBs and discusses recent advances in material development and interfacial engineering. These insights aim to guide the development of effective strategies for meeting the performance and stability requirements of practical TF-AFASSBs.