We are pioneering LiPF₆–glyme ether electrolytes, an emerging electrolyte configuration that combines the lithium-metal compatibility of ethers with the high-voltage and aluminum compatibility of LiPF₆. This platform integrates salt–solvent phase behavior, molecular symmetry, and interfacial selectivity as coupled design variables.

Our first study showed that the apparent insolubility of LiPF₆ in conventional glymes arises from a dissociation–solvation–reprecipitation mechanism. Weak dielectric screening and glyme symmetry promote ordered Li(glyme)ₓPF₆ solvate crystals, whereas a homogeneous solubility-inverted region re-emerges above a critical concentration. These electrolytes also exhibit remarkable anodic stability, establishing the solubility foundation of this configuration.

Our EES study extends the concept to molecular design. Asymmetric fluorination disrupts crystal packing and increases LiPF₆ solubility from <0.1 M in DEE to 2.0 M, bridging dilute electrolytes and the high-concentration region. It further reveals that bulk solvation does not directly determine the anode interphase. Glyme reduction dominates the SEI, while FEC redirects reduction chemistry and improves lithium reversibility. Meanwhile, PF₆⁻ suppresses aluminum corrosion and enables NCM811 operation up to 4.8 V, supporting a fluorine-efficient, high-voltage lithium-metal battery platform.

The LiPF₆–glyme ether system is full of high-hanging fruit and rich insights that are difficult to uncover, but well worth the effort. We have more exciting discoveries on the way!