Coupling LiF Dissolution Chemistry with Solvation Regulation for High-Power and Wide-Temperature Li/CF x Batteries

Abstract

Lithium/fluorinated carbon (Li/CFx) batteries are promising for mission-critical power sources, but their practical performance is hindered by solvent-dominated Li+ solvation and insulating LiF accumulation. Herein, 2-fluoro-6-methoxyphenylboronic acid (FMPB) is introduced as a dual-functional electrolyte additive to regulate LiF dissolution and Li+ solvation. Experimental and theoretical analyses reveal that the Lewis acidic B center promotes B−F coordination, lowering LiF dissociation energy and facilitating LiF dissolution. Meanwhile, electronegative O and electron-deficient B sites induce BF4− participation in the inner solvation sheath, accelerating Li+ desolvation and constructing an inorganic-rich interphase. Benefiting from these synergistic effects, Li/CFx batteries achieve a record-high power density of 88,661 W kg−1 at 492.4 Wh kg−1 (30 °C, 50 A g−1) and stable operation from −35 to 60 °C. A 2 Ah pouch cell delivers 460.3 Wh kg−1 based on the entire cell mass. This work provides a strategy for electrolyte design in high-power Li/CFx batteries.