LiSICON-Ionic Liquid Electrolyte for Lithium Ion Battery.

摘要

Current lithium ion batteries (LiB) have limited usefulness in high temperature applications due to the flammable of the organic electrolyte. Alternatively, solid electrolytes can mitigate safety issues and enable high temperature applications. Here, a new solid-statelithium ion battery design is investigated using LiSICON as the electrolyte. To reduce the interfacial resistance between the solid electrolyte and graphite electrode, an ionic liquid was used as the ionic conductor. N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl) imide(PYR13+FSI-) was used as the ionic liquid due to its high efficiency forlithiation/delithiaion. The cell capacity and efficiency was measured attemperatures from 25 deg C to 120 deg C. The lithium salt concentration in the ionic liquid was found to change the electrolyte reduction potential. A stable solid electrolyte interface (SEI) was achieved by adjusting the lithium salt concentration in the wetting agent. Impedancespectroscopy was performed to study the cell behavior with different Li salt concentrations at elevated temperature. A carbon anode in a LiSICONcell with 0.75M LiTFSI/PYR13+FSI- had a capacity of 325 mAh g-1 and coulombic efficiency of 99.8% during cycling at 80 deg C.