Design Criteria of Dilute Ether Electrolytes toward Reversible and Fast Intercalation Chemistry of Graphite Anode in Li-Ion Batteries
Dawei Xia, Ethan P. Kamphaus, Anyang Hu, Sooyeon Hwang, Lei Tao, Sami Sainio, Dennis Nordlund, Yanbao Fu, Haibo Huang, Lei Cheng, Feng Lin
Abstract
To date, dilute ether electrolytes have been believed to be incompatible with graphite in Li-ion batteries due to the detrimental solvent cointercalation and graphite exfoliation. Here, we provide design criteria of dilute ether electrolytes for a reversible graphite anode based on tailoring the solvation structures and thermodynamic properties. We clarify that ether solvents can support graphite reversibly by modulating the anion. Our redesigned electrolyte consisting of a single-solvent 1,3-dioxolane (DOL) and 1 M single-salt lithium bis(fluorosulfonyl)imide (LiFSI) shows weakened Li-solvent interaction and results in an inorganic-rich solid-electrolyte interphase. Consequently, we achieved ∼99.9% Coulombic efficiency with >96% capacity retention (∼350 mAh/g) after 300 cycles at C/5 using natural graphite. The weakly solvated electrolyte maintains desirable transport properties, enabling better rate capability than carbonate electrolytes with an areal capacity of 2–4 mAh/cm 2 . We have demonstrated the potential of dilute ether electrolytes for facile desolvation-based intercalation chemistry in graphite, creating a viable path toward fast-charge Li batteries.