文章信息/Info

Title:

 Study on Functional Electrolytes Based on Ionic Liquid for Rechargeable Lithium Battery

作者:

 朱奇珍;  陳楠;  陳人杰;  吳鋒

 北京理工大學(xué) 材料學(xué)院

Author(s):

 ZHU Qizhen;  CHEN Nan;  CHEN Renjie;  WU Feng

 School of Material， Beijing Institute of Technology

關(guān)鍵詞:

 ; 電解質(zhì); 離子液體; 鋰二次電池; 電解質(zhì)體系; 半定量

DOI:

10.7502/j.issn.1674-3962.2016.06.08

文獻標志碼:

A

摘要:

 作為電池的重要組成部分，電解質(zhì)在很大程度上影響著鋰電池的安全性、溫度適應(yīng)性、充放電性能和循環(huán)壽命。研究合成了二氟草酸硼酸鋰(LiODFB)�睳�布谆��睳�布籽趸�乙基吡咯烷雙(三氟磺酰亞胺)(Pyr1,2O1TFSI) /亞硫酸酯電解質(zhì)，展現(xiàn)出良好的離子傳導(dǎo)性、電極相容性和寬工作溫度范圍，其中LiODFB�睵yr1,2O1TFSI/DMS電解質(zhì)體系的電導(dǎo)率和鋰離子遷移數(shù)分別為8.163×10-3 S·cm-1，0.28。首次將離子液體基電解質(zhì)體系的應(yīng)用溫度范圍拓展到-40 ℃，使Li/MCMB電池和Li/ LiFePO4電池在-40~60 ℃的工作溫度范圍內(nèi)均表現(xiàn)出理想的電化學(xué)性能。以Li［(NSO2CF3)2］ (LiTFSI)作為鋰鹽，將三(乙二醇)二甲醚(TEGDME)作為共溶劑，結(jié)合離子液體Pyr1,2O1TFSI，制備系列Li/S電池電解質(zhì)。含LiTFSI��(70wt%)Pyr1,2O1TFSI/ (30wt%)TEGDME電解質(zhì)的Li/S電池表現(xiàn)出優(yōu)秀的循環(huán)性能和倍率性能，在0.1 C充放電倍率下，首周循環(huán)周期放電比容量1 212.8 mAh·g-1，循環(huán)100周后仍然維持在693.5 mAh·g-1。在1 C放電倍率下，循環(huán)100周放電比容量約為827.3 mAh·g-1，庫倫效率達到99%以上。同時，該電解質(zhì)還具有良好的高溫性能，電池在80 ℃仍然可以正常工作，放電容量達1 005.3 mAh·g-1。在總結(jié)相關(guān)研究工作的基礎(chǔ)上，從離子液體/有機共溶劑電解質(zhì)體系出發(fā)，首次半定量對離子液體/共溶劑體系和電化學(xué)基本性質(zhì)間的構(gòu)效關(guān)系進行了深入分析，對未來面向不同應(yīng)用方向的鋰二次電池電解質(zhì)體系的設(shè)計合成具有一定的理論意義和參考價值。

Abstract:

 As a key component of a battery, electrolyte has a potent influence on its safety, operating temperature, charge/discharge performance and cycle life. Novel electrolytes were prepared based on (N�瞞ethoxyethyl�睳�瞞ethylpyrrolidinium bis (trifluoromethanesulfonyl)�瞚mide, Pyr1,2O1TFSI) and sulfites as co�瞫olvents with lithium difluoro (oxalate) borate (LiODFB) as lithium salt, exhibiting good ion transport, electrode compatibility and wide operating temperature range. The conductivity and Li+ transference number of the LiODFB�睵yr1,2O1TFSI/ DMS electrolyte was 8.163×10-3 S·cm-1 and 0.28, respectively. The Li/MCMB and Li/ LiFePO4 cells containing this electrolyte had good cycle performance and normal charge curve in the temperature of-40 ℃ to 60 ℃. Moreover, a series of electrolytes for Li/S battery were prepared based on Pyr1,2O1TFSI) with tris(ethylene glycol) dimethyl ether (TEGDME) as co�瞫olvents in different proportions. LiTFSI was used as lithium salt. Li/S cells with LiTFSI��(70wt%)Pyr1,2O1TFSI/ (30wt%)TEGDME electrolyte exhibited excellent cycle and rate performance, whose capacity was 1 212.8 mAh·g-1 in the first cycle and 693.5 mAh·g-1 after 100 cycles at current density of 0.1 C, and 827.3 mAh·g-1 with the coulombic efficiency of above 99% at current density of 1 C. In addition, the cells showed good high temperature performance which could operate at 80 ℃ with the initial cycle capacity of 1 005.3 mAh·g-1. A summary of representative electrolyte systems of ionic liquid with organic co�瞫olvent for lithium battery and the corresponding characteristics and properties based on the investigations above and the previous studies are illustrated for the first time. It might be proposed to offer a useful starting point to design the mixed electrolyte in lithium batteries.