Spectroscopic investigation of new room-temperature molten salt based on LiTFSI with acetamide

New room-temperature molten salt based on lithium bis (trifluoro methane sucfone) imide (LiTFSI) and acetamide with a proper molar ratio has an excellent thermal stability and electrochemical performance. The action mechanism was studied by FTIR spectroscopy, FT-Raman spectroscopy and quantum chemistry calculation with nonlocal DFT. The vibrational spectra and calculated results show that acetamide can coordinate with Li⁺ cation in LiTFSI through Li-O bonding, and electrovalent bonding of LiTFSI was destroyed. A big coordinate cation formed and its positive charge was shielded in acetamide molecule. Charges of TFSI^- ion were partly off resulting in to shielding of charges in the whole molecule by the terminal CF₃ group. The coulombic forces was very weakly between the cations and anions, and the coordination of Li-O can also cause the breakage of hydrogen bonding between acetamide molecules, resulting in the formation of this molten salt in the liquid state.