Emergence of One-Dimensional Interstitial Anionic Superconductivity in Li–F System under High Pressure

Inspired by lithium-based electrides with pressure-induced superconductivity (e.g., Li8Au, Li6P, and Li6As), we performed first-principles calculations on LinFm (n = 1–11, m = 1–3). By incorporating zero-point energy (ZPE) and van der Waals (vdW) interactions, we obtained convex hulls distinct from previous reports and identified four phases with 1D interstitial anionic electrons (IAEs): stable P1̅-Li9F at 50 GPa; metastable C2-Li6F at 50 GPa, P21/c-Li5F2 at 100 GPa, and P1̅-Li10F at 50 GPa. All four compounds are predicted to be high-pressure, phonon-mediated superconductors, albeit with distinct origins of the superconducting carriers. Among them, Li10F exhibits the strongest electron–phonon coupling (EPC) constant λ = 0.873 and the highest superconducting critical temperature (Tc ≈ 10 K). More remarkablely, our study indicates that Li-associated IAEs play a significant role in the superconductivity of Li10F. Our work not only predicts the first example of superconductivity in lithium halides but also highlights the crucial role of IAEs in influencing superconductivity.