Effect of Zwitterionic Additive on Electrode Protection through Electrochemical Performances of Anatase TiO(2) Nanotube Array Electrode in Ionic Liquid Electrolyte

In this work, a functionalized zwitterionic (ZI) compound 1-butylsulfonate-3-methylimidazole (C(1)C(4)imSO(3)) was synthesized and tested as an additive to LiTFSI/C(2)C(2)imTFSI ionic liquid-based electrolytes for lithium-ion batteries. The structure and purity of C(1)C(4)imSO(3) were confirmed by NMR and FTIR spectroscopy. The thermal stability of the pure C(1)C(4)imSO(3) was examined by simultaneous thermogravimetric–mass spectrometric (TG–MS) measurements and differential scanning calorimetry (DSC). The LiTFSI/C(2)C(2)imTFSI/C(1)C(4)imSO(3) system was tested as a potential electrolyte for lithium-ion batteries by using anatase TiO(2) nanotube array electrode as the anode material. This electrolyte with 3% C(1)C(4)imSO(3) showed significant improvement of lithium-ion intercalation/deintercalation properties, such as capacity retention and Coulombic efficiency compared to electrolyte without additive.