電場誘導高離子導向之混摻高分子固態電解質

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71340

Title:	電場誘導高離子導向之混摻高分子固態電解質
Authors:	張倚涵;Chang,Yi-Han
Contributors:	化學學系
Keywords:	固態電解質;混摻高分子;離子液體;電場誘導;鋰離子二次電池
Date:	2016-07-26
Issue Date:	2016-10-13 12:45:33 (UTC+8)
Publisher:	國立中央大學
Abstract:	鋰離子二次電池廣泛使用在各個電子產品與行動裝置，為重要儲能裝置之一；由於一般鋰電池之電解液在使用上，有安全性上之隱憂，因此發展不具揮發性之固態電解質為解決此問題之方法之一。本研究利用兩種不同比例之PMMA及PVDF-HFP高分子混摻及非揮發性離子液體之結合，於電場誘導極化下製成高離子導電度之固態電解質。在電場中，非結晶區之高分子鏈形成有序之排列；結晶區結晶度下降，提供鋰離子有更多之運動空間，增加導離子導電度，此系統之樣品之導電度皆可達10-3 S/cm以上。尤其是主體高分子比例為PVDF-HFP:PMMA=50:50電場處理後之e5EL樣品，在溫度70oC，導電度可高達10-2 S/cm。由於電場誘導之結構上的改變，非結晶區形成長程有序的排列，進而使薄膜緻密化，不但增加薄膜之機械強度提高PVDF-HFP/PMMA之相容性，伴隨著提升薄膜之熱穩定性及電化學穩定性，電化學視窗最高可達5.58 V。此外電解質與電極之介面電阻也由於PMMA及電場極化之效應得以改善。電性測試上，在0.1C時，皆都可達120mAh/g以上，e5EL電容量可達150mAh/g，而在0.5C充放電速率下，e3EL電容量可以達70mAh/g，在庫倫效率，皆可達100%左右。 ;Lithium-ion battery holds great promises for automobile applications and for energy storage purpose. In this work, we present a highly ion conducting solid polymer electrolytes (SPEs) membrane, prepared under external electric field (EF) poling where nonvolatile conducting medium, ionic liquids (ILs) in solid polymer electrolytes. The poling created aligned morphology in PVDF-HFP and PMMA blending system yielding long-range ordered morphology, but remains nearly total amorphous where nonflammable ionic liquids is fully dispersed to deliver unusually high Li+ transport. Room temperature conductivity reached above 10-3S/cm and the highest conductivity of 10-2 S/cm is observed at 70oC for polymer electrolyte containing PMMA/PVDF-HFP (50/50 wt%, e5EL). The alignment by the external electric field not only altered the interaction between polymer components which has suppressed PVDF-HPF crystallinity in the SPEs, but it also improves mechanical strength of the membrane, and reduced the electrode-electrolyte interface resistance. The coin cell (R2032) using e5EL, e4EL and e3EL as the SPEs and LiFePO4 cathode shows fair half-cell performance and durable cycle stability. Under 0.1C-rate the half-cell displayed discharge capacity which could above a1most 120 mAh/g, and at 0.5C-rate the capacity reached above 60mAh/g , especially e3EL reached 70mAh/g.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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