本文關(guān)鍵詞： 固態(tài)聚合物電解質(zhì) 聚碳酸酯 縮聚 高電壓 鋰離子電池　出處：《青島科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：液態(tài)鋰離子電池中的電解液普遍存在易揮發(fā)、易燃的特點(diǎn),在使用過程中存在安全隱患,固態(tài)聚合物電解質(zhì)因?yàn)榭梢杂行У慕鉀Q電解液這方面的缺陷而受到廣泛關(guān)注。聚合物電解質(zhì)同時(shí)具有質(zhì)量輕、粘彈性好,易成膜等優(yōu)點(diǎn),用其組裝的鋰離子電池已經(jīng)為手機(jī)、筆記本電腦等電子設(shè)備提供了高效電源。隨著電極材料的不斷進(jìn)步,聚合物電解質(zhì)已經(jīng)成為決定固態(tài)聚合物鋰離子電池性能的關(guān)鍵材料。(1)本論文利用酯交換反應(yīng)合成了兩種新型的聚碳酸酯,聚二乙二醇碳酸酯(PDEC)和聚三乙二醇碳酸酯(PTEC)在室溫下均為無定形態(tài)的淡黃色蠟狀固體,并且玻璃化轉(zhuǎn)變溫度均在-20 oC以下,有利于其在鋰離子電池聚合物電解質(zhì)中的使用。選擇碳酸二乙酯與二元醇摩爾比為1.2:1,這樣保證了酯交換反應(yīng)的充分,制備出的聚碳酸酯分子量在8000 g·mol-1左右。(2)通過溶液澆鑄法制備出兩種聚合物電解質(zhì)膜,分別為PDEC-LiTFSI和PTEC-LiTFSI與纖維素復(fù)合電解質(zhì)膜。PTEC-LiTFSI比PDEC-LiTFSI的離子電導(dǎo)率高,是因?yàn)镻TEC具有比PDEC更低的玻璃化轉(zhuǎn)變溫度,分子鏈段運(yùn)動(dòng)活性更強(qiáng)。實(shí)驗(yàn)結(jié)果證明,篩選出的PTEC基電解質(zhì)在25 oC下的離子電導(dǎo)率為1.12×10-5S·cm-1,鋰離子遷移數(shù)為0.39,電化學(xué)窗口可以達(dá)到4.5 V。用PTEC基電解質(zhì)組裝的LiFePO_4半電池在室溫0.05 C倍率下可以可逆的充放電。此外,PTEC基組裝的高電壓LiFe_(0.2)Mn_(0.8)PO_4半電池(截止電壓4.35 V),在室溫下具有很好的倍率性能和循環(huán)穩(wěn)定性。(3)設(shè)計(jì)并合成了新型的氟代聚碳酸酯,聚四氟丁烷碳酸酯(PTFBC),室溫下PTFBC為白色固體粉末,重均分子量為207500 g mol-1,分散度為2.3,熔融溫度為105.2 oC。通過溶液澆鑄法制備的聚合物電解質(zhì)膜,形貌上平整且致密。該薄膜具有良好的阻燃效果,在室溫下離子電導(dǎo)率可以達(dá)到1.31×10-4 S·cm-1,電化學(xué)穩(wěn)定窗口可以達(dá)到5 V,鋰離子遷移數(shù)為0.52。PTFBC聚合物電解質(zhì)優(yōu)異的電化學(xué)性能使其在高電壓電池體系中的應(yīng)用具有光明的前景。
[Abstract]:The electrolyte in lithium-ion battery is volatile and flammable. Solid polymer electrolytes have attracted wide attention because they can effectively solve the defects in electrolyte. Polymer electrolytes also have the advantages of light weight, good viscoelasticity and easy film formation. The lithium ion batteries assembled with them have been used for mobile phones. Laptop computers and other electronic devices provide efficient power supply. With the development of electrode materials, Polymer electrolyte has become the key material to determine the performance of solid-state polymer lithium-ion battery. In this paper, two new polycarbonate were synthesized by transesterification. Poly (ethylene glycol carbonate) (PDEC) and poly (triethylene glycol carbonate) (PTEC) are amorphous yellowish waxy solids at room temperature, and the glass transition temperature is below -20oC. The molar ratio of diethyl carbonate to diol is 1.2: 1, which ensures the sufficient transesterification. The molecular weight of the prepared polycarbonate was about 8000 g 路mol-1. (2) two kinds of polymer electrolyte membranes were prepared by solution casting. They were PDEC-LiTFSI and PTEC-LiTFSI / Cellulose composite electrolyte membranes. PTEC-LiTFSI had higher ionic conductivity than PDEC-LiTFSI. This is because PTEC has a lower glass transition temperature than PDEC and is more active in segment motion. The ionic conductivity of the selected PTEC based electrolyte is 1.12 脳 10 ~ (-5) S 路cm ~ (-1), the number of lithium ion migration is 0.39, and the electrochemical window can reach 4.5 V. the LiFePO_4 half-cell assembled with PTEC based electrolyte can be reversibly charged and discharged at the rate of 0.05C at room temperature. In addition, a novel fluorinated polycarbonate was designed and synthesized by a high voltage LiFe_(0.2)Mn_(0.8)PO_4 half-cell (cutoff voltage 4.35V, with good rate performance and cyclic stability at room temperature). Polytetrafluorobutane carbonate (PTFB C), PTFBC is a white solid powder at room temperature, the weight average molecular weight is 207500 g mol -1, the dispersion is 2.3, and the melting temperature is 105.2oC. the polymer electrolyte membrane was prepared by solution casting method. The film has good flame-retardant effect. At room temperature, the ionic conductivity can reach 1.31 脳 10 ~ (-4) S 路cm ~ (-1), the electrochemical stability window can reach 5 V, the lithium ion mobility number is 0.52.PTFBC polymer electrolyte has excellent electrochemical performance, so it has a bright future in high-voltage battery system.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ317;TM912

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 謝興益,李潔華,何成生,樊翠蓉,鐘銀屏;脂肪族聚碳酸酯二醇的合成與表征[J];高分子材料科學(xué)與工程;2002年04期

2 陳立班;二氧化碳共聚物的合成、性質(zhì)和應(yīng)用[J];高分子通報(bào);1999年03期

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本文編號：1496750