| Summary: | 碩士 === 國立雲林科技大學 === 化學工程與材料工程研究所 === 95 === This study investigates the transport characteristics of binary lithium bis(trifluoromethane sulfone)imide (LiN(SO2CF3)2, LiTFSI)-urea room temperature molten salts which is considered to used as the electrolyte for Li ion secondary battery. The differential scanning calorimetry (DSC) was used for obtaining the phase diagram of the binary system. It was observed that when the mole ratio of LiTFSI and urea was 20:80 mol%, this system had the lowest eutectic point of 230.19 K. The conductivity of the binary molten salt increased with increasing temperature and urea content, whereas the density decreased with increasing temperature and urea content. The activation energies of equivalent conductivity of the binary system were 26.85, 36.49, and 50.34 kJ/mol when the contents of LiTFSI were 20, 30, and 40 mol%, respectively. The effects of temperature and composition on conductivity and density can be explained by the intermolecular force between the complex ions of the solute-solvent.
Lithium manganese oxide thin film with spinel structure was prepared by radio frequency magnetron sputtering. The effects of the sputtering power (80W) and the sputtering pressure (10 and 50 mTorr) on the structure and the characteristics of LiMn2O4 thin film were thus studied. The addition of small amount of the binary LiTFSI-urea room temperature molten salt electrolyte was in the commercial electrolyte（1M LiPF6 in EC/DEC (1:1 in vol.)）. A LiMn2O4¬︱commercial electrolyte/RTMS︱Li coin cell was fabricated in a glove-box filled with argon environment and was tested charge/discharge property. The crystal structure and the surface morphology of the thin film were investigated by using x-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The room temperature molten salts were used as additives in the commercial electrolytes for evaluating its effects of conductivity and nonflammable property.
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