Tailoring Artificial Solid Electrolyte Interphase via MoS2 Sacrificial Thin Film for Li-Free All-Solid-State Batteries

Anode-free all-solid-state batteries (AFASSBs) are potential candidates for next-generation electric mobility devices that offer superior energy density and stability by eliminating Li from the anode. However, despite its potential to stabilize the interface between sulfide solid electrolytes (SEs) and anode-free current collectors (CCs) efficiently, a controllable approach to incorporating MoS₂ into AFASSBs has not yet been found. Herein, we propose a strategy for stabilizing the interface of Li-free all-solid-state batteries using controllable MoS₂ sacrificial thin films. MoS₂ was controllably grown on CCs by metal-organic chemical vapor deposition, and the MoS₂ sacrificial layer in contact with the SEs formed an interlayer composed of Mo metal and Li₂S through a conversion reaction. In the AFASSBs with MoS₂, Mo significantly reduces the nucleation overpotential of Li, which results in uniform Li plating. In addition, MoS₂-based Li₂S facilitates the formation of a uniform and robust SE interface, thereby enhancing the stability of AFASSBs. Based on these advantages, cells fabricated with MoS₂ exhibited better performance as both asymmetrical and full cells with LiNi_0.6Co_0.2Mn_0.2O₂ cathodes than did cells without MoS₂. Moreover, the cell performance was affected by the MoS₂ size, and full cells having an optimal MoS₂ thickness demonstrated a 1.18-fold increase in the initial discharge capacity and a sevenfold improvement in capacity retention relative to SUS CCs. This study offers a promising path for exploiting the full potential of MoS₂ for interface stabilization and efficient AFASSB applications.