“Water-in-salt”聚合物电解质制备及其电化学性能研究

doi:10.13208/j.electrochem.201250

摘要/Abstract

摘要：

为提高柔性锂离子电池安全性和循环稳定性能,本实验以自由基聚合结合冷冻干燥得到的聚丙烯酰胺膜为电解质载体,引入21 mol·kg^-1 LiTFSI 高浓度电解液,得到“water-in-salt”聚合物电解质。通过聚合物膜的形貌和孔道结构表征,红外光谱分析,离子电导率及电化学稳定窗口测试等对其基本物化特性进行了研究。冷冻干燥得到的聚丙烯酰胺膜内部具有大量微孔结构,有利于电解液的载入。将该吸附了电解液的聚合物电解质膜与锰酸锂(LiMn₂O₄)正极和磷酸钛锂(LiTi₂(PO₄)₃)负极组装全电池进行充放电性能测试。结果表明,制得的柔性聚合物电解质具有良好的拉伸性能,高离子电导率(20°C,4.34 mS·cm^-1)和宽电化学稳定窗口(3.12 V)。以“water-in-salt”聚合物电解质为隔膜组装的LiMn₂O₄||LiTi₂(PO₄)₃ 全电池表现出优异的倍率性能和长循环稳定性。

关键词: “water-in-salt”电解液, 准固态锂离子电池, 聚合物电解质

Abstract:

Since the development of wearable and flexible electronic products, the demand of flexible energy storage devices such as batteries and super capacitors is in urgent. To enhance the safety and cycling stability for flexible lithium-ion batteries, “water-in-salt” polymer electrolyte was prepared by introducing 21 mol·kg^-1 LiTFSI electrolyte into cross-linked polyacrylamide (PAM) after freeze-drying. A great amount of holes with the size range of 10 ~ 20 μm can be found on the surface and in the bulk of polyacrylamide, which is benefited from the freeze-drying process and acts as a great support for the electrolyte uptake. The “water-in-salt” polymer electrolyte showed good tensile property, high ionic conductivity (4.34 mS·cm^-1 at 20℃), and broadened electrochemical stability window (ESW, 3.12 V). Comparing the FTIR spectra of PAM, “water-in-salt” electrolyte (WiSE) and WiSE-PAM, the signal that can be assigned to H-O bending mode transfered from 3186 cm^-1 in PAM to higher wavenumber of 3560 cm^-1 in WiSE-PAM. Therefore, it can be inferred that the amide group in PAM participates in the Li⁺ solvation sheath in WiSE-PAM electrolyte, due to the hydrogen bond between amide group and water. On the one hand, the Li⁺ solvation sheath can transfer through the polymer bone and the liquid in the hole, resulting in high ionic conductivity. On the other hand, due to the hydrogen bond between amide group in PAM bone and free water, the enrichment of free water along the polymer bone can be obtained. Therefore, the free water content on the electrode surface is reduced, resulting in expanded ESW. With this polymer electrolyte, LiMn₂O₄||LiTi₂(PO₄)₃ full cell showed high initial charge/discharge capacity (68.1/62.1 mAh·g^-1) and coulombic efficiency (91.2%) at 1 C. The high capacity retention of 94.2% (with discharge capacity of 58.5 mAh·g^-1) could be obtained after 100 cycles. To evaluate the rate capability, the cells were charged and discharged at different current densities varying from 1 C to 30 C. The remarkable capacity of 28.1 mAh·g^-1 was still retained even at 30 C. After the rate test, the current was decreased back to 1 C, there was still 99.2% of the initial capacity could be recovered. In addition, when cycling at 10 C rate, 79% of the initial capacity was retained even over 5000 cycles. There results demonstrate that the full cell also showed superior rate capability and long-term cycling stability. This work offers an idea for the electrolyte design with high safety to enable the application of high-performance aqueous lithium-ion batteries in flexible electronics.

Key words: water-in-salt electrolyte, quasi-solid-state lithium-ion batteries, polymer electrolyte

侯旭, 何欣, 李劼. “Water-in-salt”聚合物电解质制备及其电化学性能研究[J]. 电化学（中英文）, 2021, 27(2): 202-207.

Xu Hou, Xin He, Jie Li. Preparation and Characterization of “Water-in-Salt” Polymer Electrolyte for Lithium-Ion Batteries[J]. Journal of Electrochemistry, 2021, 27(2): 202-207.

图/表 5

图1

图2

图3

图4

图5

参考文献 13

[1]	Fang Z H, Wang J, Wu H C, Li Q Q, Fan S S, Wang J P. Progress and challenges of flexible lithium ion batteries[J]. J. Power Sources, 2020,454(1):227932-227948. doi: 10.1016/j.jpowsour.2020.227932 URL
[2]	Li W, Dahn J R, Wainwright D S. Rechargeable lithium batteries with aqueous electrolytes[J]. Science, 1994,264(5162):1115-1118. doi: 10.1126/science.264.5162.1115 URL
[3]	Liu Z X, Huang Y, Huang Y, Yang Q, Li X L, Huang Z D, Zhi C Y. Voltage issue of aqueous rechargeable metal-ion batteries[J]. Chem. Soc. Rev., 2020,49(1):180-232. doi: 10.1039/C9CS00131J URL
[4]	Tron A, Park Y D, Mun J. AlF₃-coated LiMn₂O₄ as cathode material for aqueous rechargeable lithium battery with improved cycling stability[J]. J. Power Sources, 2016,325(1):360-364. doi: 10.1016/j.jpowsour.2016.06.049 URL
[5]	Suo L M, Borodin O, Gao T, Olguin M, Ho J, Fan X L, Luo C, Wang C S, Xu K. “Water-in-salt” electrolyte enables high-voltage aqueous lithium-ion chemistries[J]. Science, 2015,350(6263):938-946. doi: 10.1126/science.aab1595 URL
[6]	Suo L M, Borodin O, Sun W, Fan X L, Yang C Y, Wang F, Gao T, Ma Z H, Schroeder M, von Cresce A, Russell S M, Armand M, Angell A, Xu K, Wang C S. Advanced high-voltage aqueous lithium-ion battery enabled by “water-in-bisalt” electrolyte[J]. Angew. Chem. Int. Ed., 2016,55(25):7136-7141. doi: 10.1002/anie.201602397 URL
[7]	Suo L M, Oh D, Lin Y X, Zhuo Z Q, Borodin O, Gao T, Wang F, Kushima A, Wang Z Q, Kim H C, Qi Y, Yang W L, Pan F, Li J, Xu K, Wang C S. How solid-electrolyte interphase forms in aqueous electrolytes[J]. J. Am. Chem. Soc., 2017,139(51):18670-18680. doi: 10.1021/jacs.7b10688 URL
[8]	Liu Z X, Li H F, Zhu M S, Huang Y, Tang Z J, Pei Z X, Wang Z F, Shi Z C, Liu J, Huang Y, Zhi C Y. Towards wearable electronic devices: a quasi-solid-state aqueous lithium-ion battery with outstanding stability, flexibility, safety and breathability[J]. Nano Energy, 2018,44(1):164-173. doi: 10.1016/j.nanoen.2017.12.006 URL
[9]	Raymond S, Weintraub L. Acrylamide gel as a supporting medium for zone electrophoresis[J]. Science, 1959,130(3377):711.
[10]	Entry J A, Sojka R E, Watwood M, Ross C. Polyacrylamide preparations for protection of water quality threatened by agricultural runoff contaminants[J]. Environ. Pollut., 2002,120(2):191-200. doi: 10.1016/S0269-7491(02)00160-4 URL
[11]	Li H F, Liu Z X, Liang G J, Huang Y, Huan Y, Zhu M S, Pei Z X, Xue Q, Tang Z J, Wang Y K, Li B H, Zhi C Y. Waterproof and tailorable elastic rechargeable yarn zinc ion batteries by a cross-linked polyacrylamide electrolyte[J]. ACS Nano, 2018,12(4):3140-3148. doi: 10.1021/acsnano.7b09003 URL
[12]	He X, Yan B, Zhang X, Liu Z G, Bresser D, Wang J, Wang R, Cao X, Su Y X, Jia H, Grey C P, Frielinghaus H, Truhlar D G, Winter M, Li J, Paillard E. Fluorine-free water-in-ionomer electrolytes for sustainable lithium-ion batteries[J]. Nat. Commun., 2018,9(1):5320-5328. doi: 10.1038/s41467-018-07331-6 URL
[13]	Luo J Y, Chen L J, Zhao Y J, He P, Xia Y Y. The effect of oxygen vacancies on the structure and electrochemistry of LiTi₂(PO₄)₃ for lithium-ion batteries: A combined experimental and theoretical study[J]. J. Power Sources, 2009,194(2):1075-1080. doi: 10.1016/j.jpowsour.2009.06.050 URL

[1]	周莉, 吴勰, 薛照明. 热塑性聚氨酯基聚合物电解质的制备与表征[J]. 电化学（中英文）, 2021, 27(4): 439-448.
[2]	张运丰, 王佳颖, 李晓洁, 赵诗宇, 何阳, 霍士康, 王雅莹, 谭畅. 锂金属电池用三维半互穿网络聚合物电解质的制备[J]. 电化学（中英文）, 2021, 27(4): 413-422.
[3]	张运丰, 董佳明, 谭畅, 霍士康, 王佳颖, 何阳, 王雅莹. Li-SGO掺杂半互穿网络型多孔单离子传导聚合物复合电解质的制备[J]. 电化学（中英文）, 2021, 27(1): 108-117.
[4]	潘晓娜, 刘丽来, 王治璞, 王丹, 李云, 杨培霞, 张锦秋, 安茂忠. 离子液体凝胶聚合物电解质的三元组分相互作用研究[J]. 电化学（中英文）, 2020, 26(3): 406-412.
[5]	户献雷, 梁晓旭, 章明秋, 张若昕, 张利萍, 阮文红. 不同锂盐对超支化/梳状复合型聚合物电解质的性能影响研究[J]. 电化学（中英文）, 2016, 22(5): 535-541.
[6]	谭力盛, 潘婧, 李瑶, 庄林, 陆君涛. 碱性聚合物电解质燃料电池电极疏水性对性能的影响[J]. 电化学（中英文）, 2013, 19(3): 199-203.
[7]	许开卿，范乐庆，吴季怀，冷晴，钟欣，林建明，黄妙良，兰章. 聚乙烯醇基水凝胶聚合物电解质超级电容器的研究[J]. 电化学（中英文）, 2011, 17(2): 190-194.
[8]	赵亮, 胡勇胜, 李泓, 王兆翔, 徐红星, 黄学杰, 陈立泉. 拉曼光谱在锂离子电池研究中的应用[J]. 电化学（中英文）, 2011, 17(1): 12-23.
[9]	伍伟峰, 杨长春, 贺素姣, 张兵兵, 徐松, . MCM-48改性PVDF-HFP复合多孔型聚合物电解质[J]. 电化学（中英文）, 2009, 15(3): 315-319.
[10]	叶霖;赵玉美;张晓雯;冯增国;白莹;吴锋;. 纳米SiO_2复合的梳状聚醚聚合物电解质的导电性能研究[J]. 电化学（中英文）, 2007, 13(1): 19-24.
[11]	孟祥利, 殷金玲, 任娟, 张宝宏, . PMMA基凝胶聚合物电解质双电层电容器的研究[J]. 电化学（中英文）, 2007, 13(1): 101-105.
[12]	叶霖;高鹏;冯增国;吴锋;陈实;王国庆;. 梳形聚醚全固态聚合物电解质的电导率研究[J]. 电化学（中英文）, 2006, 12(1): 29-34.
[13]	袁安保;赵俊;. PVA-CMC-KOH-H_2O碱性聚合物电解质研究[J]. 电化学（中英文）, 2006, 12(1): 40-45.
[14]	陈作锋,姜艳霞,庄全超,董全峰,孙世刚. MCM-41介孔分子筛掺杂的微孔型聚合物电解质的制备与表征[J]. 电化学（中英文）, 2005, 11(2): 162-166.
[15]	刘玉文,张勇,李小龙,顾琪萍,张翠芬,黄玉东. 增塑聚合物电解质电化学性能[J]. 电化学（中英文）, 2005, 11(1): 96-100.