| Summary: | 碩士 === 逢甲大學 === 材料科學所 === 100 === Perfluorosulfonic acid (Nafion) solution as a polymer binder for lithium ion batteries has been investigated. Lithiated Nafion (Li+Nafion) ionomer have been used to replace the commercial adhesive PVdF. The Li+Nafion solution have been formed by a lithium ion exchange procedure to be the lithium-contained intelligent binder. The Li+Nafion solution is characterized by Fourier transform infrared spectroscopy. Powder cathodes fabricated by mixing LiMn2O4 powder, carbon black and binders have been investigated. The cathodes with conventional PVDF and Li+Nafion are tested and compared separately. These LiMn2O4 electrodes are characterized using Scanning electron microscopy, Energy dispersive spectrometer, X-ray diffraction, Raman spectroscopy.
The electrochemical performances are measured by cyclic voltammetry and charge-discharge cycle tests. In the long term cycling tests, Li+Nafion electrodes show a stable cycle stability as well as PVdF electrodes. The results reveal that the capacities of Li+Nafion-type LiMn2O4 electrode show an better high-rate capacity 70 mAh/g than PVDF-type LiMn2O4 electrode (45 mAh/g) at 10 C. The enhanced high-rate performance of Li+Nafion-type LiMn2O4 electrode is attributed to the intelligent binder with Li-ion conductivity. The charge transfer resistances of the LiMn2O4 electrodes decreases 41 % due to the increased lithium ion concentration around the surface of the active materials by the Li+Nafion ionomer binder.
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