博碩士論文 104324004 完整後設資料紀錄

DC 欄位 語言
DC.contributor化學工程與材料工程學系zh_TW
DC.creator吳佳蓉zh_TW
DC.creatorChia-Jung Wuen_US
dc.date.accessioned2018-8-9T07:39:07Z
dc.date.available2018-8-9T07:39:07Z
dc.date.issued2018
dc.identifier.urihttp://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=104324004
dc.contributor.department化學工程與材料工程學系zh_TW
DC.description國立中央大學zh_TW
DC.descriptionNational Central Universityen_US
dc.description.abstract本研究的第一部分,主要比較離子液體1 M LiPF6/PMP-TFSI與1 M LiTFSI/PMP-TFSI與傳統有機電解液1 M LiPF6/EC-DEC應用在高電壓LiNi0.5Mn1.5O4/Li半電池的差別(藥品全名列於3-1節)。1 M LiPF6/EC-DEC電解液具有低黏度與高離子導電率,在室溫時高速2 C與低速0.1 C的放電電容值的維持率也高達91%;但是,在高電壓環境下PF6-即便能夠鈍化鋁基材,EC-DEC卻會發生氧化分解的情況而導致在長時間壽命卻不如離子液體電解液。另外,由於其本身熱穩定性不佳,因此在高溫50 oC未能有正常充放電行為。離子液體電解液中,PF6-與TFSI-都具有良好的鈍化鋁基材能力;並且在高電壓下具有>5 V(Li/Li+)的氧化極限;其本身的熱穩定性良好,因此在50 oC下能夠得到比室溫還要良好的充放電性能。這些優勢都說明了離子液體是比傳統有機還要適合做為高電壓電解液。然而,離子液體本身在室溫下的黏度高達約200 cP是傳統有機電解液的數十倍之多,因此離子液體在室溫1 C經過200圈的放電電容值的維持率高達99%,但是在高速2 C與低速0.1 C的放電電容值的維持率卻僅僅只有20-30%,是離子液體必須克服的。 延續第一部分的結果,在第二部分針對1 M LiTFSI/PMP-TFSI改質。首先在離子液體中導入有機碳酸酯成功降低離子液體的黏度,但導入碳酸酯卻伴隨嚴重的鋁腐蝕反應。因此在混合系統的基礎下(PMP-TFSI與EC-DEC 依不同比例混合,在本文以” % IL “ 表示離子液體的比例),提高鋰鹽濃度來抑制鋁腐蝕反應。在眾多嘗試中,發現2 M LiTFSI/75% IL、3 M LiTFSI/25% IL與3 M LiTFSI/50% IL成功抑制鋁腐蝕並且得到良好的循環充放電性能,其中2 M LiTFSI/75% IL與3 M LiTFSI/25% IL具有比1 M LiTFSI/100% IL更加優良的高速性能,在2 C與0.1 C放電電容值的維持率分別達到45%與60%。但是距離傳統有機的91%仍有待改進的空間。 在第二部分發現混合系統確實有其優勢但以LiTFSI作為鋰鹽的高速維持率仍有不足之處,所以在此章節將鋰鹽更換為陰離子較小的LiPF6期望得到更良好的結果。相比LiTFSI的混合系統,LiPF6展現出較高的離子導電度、較低的黏度,而且在相同濃度及比例下的側反應電流進一步被降低。因此在2 M LiPF6/25% IL、2 M LiPF6/50% IL、2 M LiPF6/75% IL、3 M LiPF6/25% IL及3 M LiPF6/50% IL都得到比LiTFSI的混合系統更加良好的200圈與2 C維持率。其中3 M LiPF6/25% IL更展現出跟傳統有機電解液相差不遠的90.9 %高速維持率而且200圈的循環壽命維持率更高於有機電解液的93%來到97%。zh_TW
dc.description.abstractIn the fist part of research, we compare the difference between ionic liquid and organic electrolyte. Organic electrolyte demonstrate low viscosity, high conductivity and high rate capability. PF6- is able to passivate Al substrate, however, EC-DEC will deposit at high voltage. Electrolyte deposition cause serious capacity fade during cyclelife. On the hand, poor thermal ability is drawback of organic electrolyte that can not charge and discharge normally. Ionic liquid electrolyte demonstrate good electrochemical stability and thermal stability, so it demonstrate nice charge/discharge properties at 50 oC. In summary, ionic liquid electrolyte is more suitiable choice for high voltage lithium ion battery. In the second part of research, introducing carbonate into ionic liquid electrolyte is the first strategy of ionic liquid electrolyte modification. However, these electrolyte are suffer from serious Al corrosion. High concentration electrolyte is a good way which inhibit Al corrosion effectively. 2 M LiTFSI/75% IL, 3 M LiTFSI/25% IL and 3 M LiTFSI/50% IL demonstrate good charge and discharge performance. 2 M LiTFSI/75% IL and 3 M LiTFSI/25% IL promising high rate performance than ionic liquid electrolyte (1 M LiTFSI/PMP-TFSI). In the third part of the research, using LiPF6 as lithium salt improve high rate performance and cyclebility. 3 M LiPF6/25% IL is the best condition of these electrolyte. Compare to oraganic electrolyte, it show competitive high rate performance and better cycle retention.en_US
DC.subject鋰離子電池zh_TW
DC.subject耐高壓電解液zh_TW
DC.title離子液體與有機碳酸酯之混合型電解液應用於高電壓LiNi0.5Mn1.5O4正極材料zh_TW
dc.language.isozh-TWzh-TW
DC.titleMixture of ionic liquid and organic carbonate electrolyte for high voltage LiNi0.5Mn1.5O4 cathodeen_US
DC.type博碩士論文zh_TW
DC.typethesisen_US
DC.publisherNational Central Universityen_US

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