Abstract

Lithium/fluorinated carbon (Li/CFx) batteries have attracted wide attention due to their ultrahigh energy density and low self-discharge rate. However, robust C-F covalent bonds of CFx and insufficient ionic conductivity of the discharge product lithium fluoride (LiF) limit the discharge platform and energy density of Li/CFx batteries at high discharge current densities. Herein, 1,1-dimethylpyrrolidinium tetrafluoroborate (DMP.BF4) is developed as an additive of the LiBF4/PC/DME electrolyte to substantially promote the energy density and the rate capability of Li/CFx batteries. The Li/CFx battery with DMP.BF4 exhibits high discharge capacity performance at 0.01C (933mAh g-1, 2442 Wh kg-1) and a remarkable high-rate capability at 10C (823mAh g-1, 1722 Wh kg-1), compared to the performance of battery using initial electrolyte (2142 Wh kg- 1 at 0.01C and 1288 Wh kg- 1 at 10C). It is found that the interaction between DMP+ and F weakens the C-F bond and Li-F bond, forms DMP-LiF coordination compound, accelerates the discharge rate and the reaction depth of the CFx cathode, and finally improves the capacity and kinetics performance of Li/CFx battery. This work provides an effective and facile strategy for ionic liquid as multifunctional additives to increase the performance of Li/CFx batteries.

Keywords Plus：CFX，PERFORMANCE

Published in CHEMICAL ENGINEERING JOURNAL，Volume505；10.1016/j.cej.2025.159325，FEB 1 2025