Realizing high-flux lithium-ion conduction by LaF${}_3$ doping in quasi-solid-state electrolytes

The inherent low ionic conductivity of PVDF-based electrolytes at room temperature and lithium dendrite penetration hinder its further application. Herein, a LaF${}_3$ doped Poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-ctfe)) quasi-solid electrolyte is developed. High-flux channels are created due to the optimization of the lithium environment that lanthanum preferentially competes coordination with anionic species for relaxing lithium hopping. Lithium carriers are therefore highly free and unbound at the molecular level, resulting in a high ionic conductivity (σ) of 0.7 mS cm${}^{-1}$ and a transfer number (t${}_{Li+}$) of 0.79 at 25 °C. Moreover, the in situ organic-inorganic LiF-rich dielectric layer effectively improves the stability and compatibility of the electrode/electrolyte interface, ensuring interfacial lithium conduction while facilitating stable Li${}^{+}$ plating/stripping. As a result, the optimized Li/ATCSE-3%/Li can deliver favorable compatibility at 0.1 and 0.3 mA cm${}^{-2}$ for stable Li${}^{+}$ plating/stripping for 2000 and 1200 h, respectively. The high-mass loading (6.4 mg cm${}^{-2}$) pouch cell delivers a stable cycling performance over 100 cycles with a capacity retention of 85.8% at 0.3 °C. This work is anticipated to provide considerable insight into the creative design of lithium transport of polymer-based for practical quasi-solid-state lithium metal batteries. (© 2024 Wiley‐VCH GmbH)