Adhesive PEG-based binder for aqueous fabrication of thick Li4Ti5O12 electrode

We report the first fully compressed Li4Ti5O12 electrode designed by an aqueous process. An adhesive, elastomeric, and lithium ion conductive PEG-based copolymer is used as a binder for the aqueous fabrication thick, flexible, and densely packed Li4Ti5O12 (LTO) electrodes. Self-adherent cathode films exceeding 200 μm in thickness and withholding high active mass loadings of 28 mg/cm2 deliver 4.2 mAh/cm2 at C/2 rate. Structurally defect-free electrodes are fabricated by casting aqueous cathode slurries onto nickel foam, dried, and hard-calendared at 10 tons/cm2. As a multifunctional material, the binder is synthesized by the copolymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA), methyl methacrylate (MMA), and isobutyl vinyl ether (IBVE) in optimal proportions. Furthermore, coordinating the binder with lithium salt is necessary for the electrode to function.

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