| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 104 === This study investigates in the distinctive features, advantages, potentials as well as obstacles upon the developing process of secondary lithium ion battery (LiB). Safety and energy efficiency issues have always been two of the long-standing barriers that hamper LiBs from being widely utilized in all fields. They usually arise because of the natural intrinsic of olefin separators material limits and herein lies the problem, that is, poor thermal-dimension stability and low electrolyte wettability. Hence, we report a method to design a cross-linkable thermal plastic polymer material by grafting PMASS side chains on PVdF. The as-synthesized grafted polymer was characterized by FITR, DSC, TGA, NMR to verify its molecular structure and thermal property. The nano-fibrous ES PVdF-MASS mat was fabricated by the electrospinning process. Its pore size distribution was also decreased by undergoing hydraulic pressing. After thermal crosslinked, the ES PVdF-MASS CR separator suffers nearly none thermal shrinkage (0.9 %), while also obtain better affinity to the electrolyte. The aforementioned separators were assembled in a containined glove box which was set with low moisturized and low oxygen. The LiBs were compared to the commercial Celgard 2325® ones. Results show that ES PVdF-MASS CR LiBs offer better electric capacity under high-speed charge-discharge cycles and work properly without any performance compromise in the 50-cycle durability test.
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