Effect of Zwitterionic Additive on Electrode Protection through Electrochemical Performances of Anatase TiO₂ Nanotube Array Electrode in Ionic Liquid Electrolyte

In this work, a functionalized zwitterionic (ZI) compound 1-butylsulfonate-3-methylimidazole (C₁C₄imSO₃) was synthesized and tested as an additive to LiTFSI/C₂C₂imTFSI ionic liquid-based electrolytes for lithium-ion batteries. The structure and purity of C₁C₄imSO₃ were confirmed by NMR and FTIR spectroscopy. The thermal stability of the pure C₁C₄imSO₃ was examined by simultaneous thermogravimetric-mass spectrometric (TG-MS) measurements and differential scanning calorimetry (DSC). The LiTFSI/C₂C₂imTFSI/C₁C₄imSO₃ system was tested as a potential electrolyte for lithium-ion batteries by using anatase TiO₂ nanotube array electrode as the anode material. This electrolyte with 3% C₁C₄imSO₃ showed significant improvement of lithium-ion intercalation/deintercalation properties, such as capacity retention and Coulombic efficiency compared to electrolyte without additive.