Functional Gelators as Cathode Materials for Lithium-Ion Batteries

Low-molecular-weight gelators bearing 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) were synthesized by amidation reactions with DiC and DMAP. The gelators formed the thermally-reversible gels in various organic solvents and electrolytes. The minimum gelation concentration against γ-BL including lithium salts increased as compared to that of neat γ-BL. The increase of minimum gelation concentration is due to the dielectric constant of γ-BL increased by addition of lithium salt. TEM image of xerogel of loose gel in γ-BL exhibited clear fibers with a diameter of ~100 nm, while the image of γ-BL including lithium salts showed slender fibers, suggesting the interruption of the growth of fibers by lithium salts. The gel strengths of the gels containing lithium salts decreased as compared to that of neat γ-BL, indicating that the lithium salts obstructed the growth of fibrous aggregation. Electrochemical measurements, including cyclic voltammetry and cell performances proved the redox property and a plateau output voltage with rapid chargingdischarging process. Although the half-cell performance is not good enough, the CV performance of the gels comfirmed the stability of the gelators.