本文選題：全固態(tài)鋰離子電池　切入點：聚硅氧烷固體電解質　出處：《中南大學》2014年碩士論文

【摘要】：由于采用熱穩(wěn)定性高的聚合物固體電解質代替可燃的液態(tài)電解質,全固態(tài)聚合物鋰離子電池具有更寬的工作溫度范圍和更好的安全性能。但是室溫電導率差的問題嚴重影響了聚合物固體電解質在鋰離子電池中的應用。本文通過對聚硅氧烷分子進行結構設計,獲得了室溫電導率高的聚硅氧烷電解質薄膜,并且制備出了寬溫度范圍的全固態(tài)鋰離子電池。 通過聚甲基含氫硅氧烷與乙烯基三(2-甲氧基乙氧基)硅烷發(fā)生硅氫加成反應合成了梳形聚氧乙烯(PEO)單接枝聚硅氧烷。使用溶劑揮發(fā)法制備了含聚硅氧烷、聚偏氟乙烯和雙三氟甲烷磺酰亞胺鋰(LiTFSI)的電解質薄膜。當LiTFSI的含量為20wt%時,此電解質在25℃和80℃的電導率分別為5.7×10-5S cm-1和4.5×104S cm-1。 在此基礎上,通過聚甲基含氫硅氧烷同時與乙烯基三(2-甲氧基乙氧基)硅烷和環(huán)[(烯丙氧基)甲基]乙烯碳酸酯反應獲得了環(huán)狀丙烯碳酸酯(PC)和梳形PEO雙接枝聚硅氧烷,采用溶劑揮發(fā)法制備了電解質薄膜。當PC/PEO為6：4,LiTFSI含量為20wt%時,電解質在25℃的電導率為1.6×104S cm-1,相比于單接枝的電解質,提高了近2倍。基于這種電解質的LiFePO4/Li電池在25℃和100℃以1C倍率循環(huán)時,初始放電比容量可分別達到88.2mAh g-1和140mAh g-1,100圈循環(huán)后的放電比容量分別為79.8mAh g-1和130mAh g-1,展現出了優(yōu)良的寬溫度工作特性。
[Abstract]:Due to the use of solid polymer electrolytes with high thermal stability instead of flammable liquid electrolytes, All solid polymer lithium-ion batteries have wider operating temperature range and better safety performance. However, the problem of low conductivity at room temperature has seriously affected the application of polymer solid electrolyte in lithium ion batteries. Structural design of polysiloxane molecules, Polysiloxane electrolyte thin films with high conductivity at room temperature were obtained and all-solid-state lithium ion batteries with wide temperature range were prepared. The comb polyoxyethylene polysiloxane (PEO) grafted polysiloxane was synthesized by hydrosiloxane and vinyl trimethoxy ethoxy) silane. The polysiloxane containing polysiloxane was prepared by solvent volatilization. The electrolyte films of poly (vinylidene fluoride) and lithium trifluoromethane sulfonimide (LiTFSI) were prepared. When the content of LiTFSI was 20 wt%, the conductivities of the electrolyte were 5.7 脳 10 ~ (-5) S cm-1 and 4.5 脳 10 ~ (4) S cm ~ (-1) at 25 鈩，

本文編號：1692772