Solvated Structure of Hybrid Tetraglyme-Aqueous Electrolyte Dissolving High-Concentration LiTFSI-LiFSI for Dual-Ion Battery

Dengyao Yang, Huan Li, Xiaofeng Shen, Motonori Watanabe, Tatsumi Ishihara

Research output: Contribution to journalArticlepeer-review

Abstract

The solvated structure of a highly concentrated hybrid tetraglyme (G4)-water electrolyte was studied for an increasing cycle stability and performance of a KS6 used dual-ion battery. Hybrid solvent of G4 and water with a weight ratio of 2 to 8 was able to dissolve 9LiFSI-1LiTFSI supporting salts up to 37 mol kg−1 (37 mol kg−1 G2W8). In spite of such high concentration of supporting salts, reasonable charge and discharge performance of dual-ion battery (discharge capacity of ≈40 mAh g−1 and coulombic efficiency of 90 %) were exhibited over 300 cycles. This was attributed to the decreased hydrogen evolution reaction (HER) potential to −1.05 V vs. Ag/AgCl by addition of G4. From Fourier-transform infrared, nuclear magnetic resonance, and Raman spectroscopies, G4 molecules were more strongly coordinated to Li+ to form ion pairs of [Li(G4)x(H2O)y]+ complex in hybrid G4-water electrolyte. Co-intercalation of bis(trifluoromethanesulfonyl)imide (TFSI) and bis(fluorosulfonyl)imide (FSI) into graphitic carbon KS6 cathode was confirmed in hybrid aqueous electrolyte.

Original languageEnglish
JournalChemSusChem
DOIs
Publication statusAccepted/In press - 2022

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Chemical Engineering(all)
  • Materials Science(all)
  • Energy(all)

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