Quaternary-ammonium Based Ionic Liquid Mixed with Organic Solvent Electrolyte System.

Ionic liquids (ILs) have been proposed as electrolytes for long-lived and safe LIBs, since they are nonflammability and have low volatility. The interactions between of cathodes (as olivine LiFePO4 or layered LiNi1/3Mn1/3Co1/3O2 (NMC)) and ionic liquid mixed with organic solvent electrolyte were investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), coin cell test, and scanning electron microscope (SEM). The mixed electrolyte contains ethylene carbonate (EC), dimethyl carbonate (DMC) and ionic liquid such as bis(trifluoromethanesulfonyl)imide (TFSI) and tetraethylammonium (N2222). The results show that the LiFePO4 cathode in this mixed electrolyte had better cycling performance than the NMC cathode. [ABSTRACT FROM AUTHOR]