Amorphous fluorinated interphase enables fast Li-ion kinetics in sulfide-based all-solid-state lithium metal batteries

Sulfide-based all-solid-state lithium metal batteries (ASSLMBs) have garnered significant attention due to their potential for high energy density and enhanced safety. However, their practical application is hindered by challenges such as uneven lithium (Li) deposition and the growth of Li dendrites. In this contribution, we propose an amorphous fluorinated interphase (AFI), composed of amorphous LiF and lithiated graphite, to regulate the interfacial Li-ion transport kinetics through in-situ interface chemistry. Amorphous LiF, which exhibits a significantly enhanced Li-ion diffusion compared to its crystalline counterpart, works synergistically with lithiated graphite to promote both short-range and long-range Li-ion transport kinetics at the Li/electrolyte interface. As a result, the Li anode with AFI demonstrates a remarkably enhanced critical current density of 1.6 mA cm⁻² and an extended cycle life exceeding 1100 h. The Li||LiNi_0.6Co_0.2Mn_0.2O₂ full cell also achieves a high discharge capacity of 125.7 mA h g⁻¹ and retains 71.2% of its initial capacity after 200 cycles. This work provides valuable insights into the rational design of artificial anodic interphase to regulate interfacial Li-ion transport kinetics in ASSLMBs.