从介观角度研究了锂离子在有机电解液锂空气电池隔膜中的传质特性。采用耗散粒子动力学DPD模拟方法,使用分子模拟软件Materials Studio构建了全氟磺酸锂(PFSA-Li)离子交换膜、有机溶剂乙二醇二甲醚(DME)与六氟磷酸锂(LiPF6)的粗粒化模型。分析了PFSA-Li膜中锂离子通道的三维拓扑结构,研究了温度、有机液体含量和锂盐浓度对PFSA-Li膜中锂离子扩散行为的影响。当PFSA-Li膜内有机液体含量达到一定程度时,离子团簇相互连接,最终形成贯穿膜的连续海绵状通道;升高温度、增加有机液体含量有利于锂离子在PFSA-Li膜中的扩散;当锂盐浓度为1mol/L时,锂离子扩散效果最佳。研究成果为有机电解液锂空气电池性能的提升提供了重要依据。
The mass transfer characteristics of lithium ion in the membranes of organics electrolyte lithium air battery were studied from a mesoscopic perspective.By using the dissipative particle dynamics DPD simulation method,the coarse-grained model of lithium perfluorinated acid (PFSA-Li) ion exchange membrane,organic solvent ethylene glycol dimethyl ether (DME) and lithium hexafluorophosphate (LiPF6) was constructed by means of molecular simulation software Materials Studio.The 3D topology of lithium-ion channels in the PFSA-Li membrane was analyzed,and studied the effects of temperature,organic liquid content and lithium salt concentration on the diffusion behavior of lithium ion in the PFSA-Li membrane.When the content of organic liquid in the PFSA-Li membrane reached a certain level,the ionic clusters were connected to each other,and finally formed a continuous cavernous channels through the membrane.Rising the temperature and increasing the content of the organic liquid were beneficial to the diffusion of lithium ion in the PFSA-Li membrane.When the concentration of lithium salt was 1 mol/L,the diffusion of lithium ion was the best.The research results provided an important basis for the improvement of the performance of the organic electrolyte type lithium air battery.
[1] Yang S, Ping H, Zhou H.Research progresses on materials and electrode design towards key challenges of Li-air batteries[J].Energy Storage Materials, 2018, 13:29-48.
[2] Bao L, Sun Y, Li L, et al.Advances in manganese-based oxides cathodic electrocatalysts for Li-air batteries[J].Advanced Functional Materials, 2018, 28(15):1704973.
[3] Bruce P G, Freunberger S A, Hardwick L J, et al.Li-O2 and Li-S batteries with high energy storage[J].Nature Materials, 2012, 11(1):19-29.
[4] Yang W, Kim D Y, Yang L, et al.Oxygen-rich lithium oxide phases formed at high pressure for potential lithium-air battery electrode[J].Advanced Science, 2017, 4(9):7029-7036.
[5] 蒋颉, 刘晓飞, 赵世勇, 等.基于有机电解液的锂空气电池研究进展[J].化学学报, 2014, 72(4):417-426.
[6] 麻微.导锂聚合物电解质膜的制备及应用[D].上海:上海交通大学, 2012.
[7] Ye H, Huang J, Xu J J, et al.Li Ion conducting polymer gel electrolytes based on ionic liquid/PVDF-HFP blends[J].Journal of the Electrochemical Society, 2007, 154(11):A1048-A1057.
[8] Zhang D, Li R, Huang, T, et al.Novel composite polymer electrolyte for lithium air batteries[J].Journal of Power Sources, 2010, 195(4):1202-1206.
[9] 郎万中, 许振良.全氟磺酸离子膜的结构与应用研究进展[J].膜科学与技术, 2005, 25(6):69-74.
[10] Liao X Z, Wang H, Li L, et al.Rechargeable Li/O2 cell based on a LiTFSI-DMMP/PFSA-Li composite electrolyte[J].Journal of the Electrochemical Society, 2012, 159(11):A1874-A1879.
[11] Carla H W.Recent advances in perfluorinated ionmomer membranes:structure, properties and applications[J].J Membr Sci, 1996, 120:1-33.
[12] Gierke T D, Munn G E, Wilson F C, et al.The morpho-logy in Nafion perfluorinate membrane product, as deter-mined by wide- and small-angle X-ray studies[J].J Polym Sci, 1981, 19:1687-1704.
[13] Lee E M, Thomas R K, Burgess A, et al.Local and long-range structure of water in a perfluorinated ionomer membrane[J].Macromol, 1992, 25(12):3106-3109.
[14] Sawada S, Yamaki T, Ozawa T, et al.Watertransport in polymer electrolyte membranes investigated by dissipativeparticle dynamics simulation[J].ECS transactions, 2010, 33(1):1067-1078.
[15] Skyllas-Kazacos M, Goh L.Modeling of vanadi-um ion diffusion across the ion exchange membrane in the vanadium redox battery[J].Journal of Membrane Science, 2012, 399(3):43-48.
[16] 唐元晖, 何彦东, 王晓林.耗散粒子动力学及其应用的新进展[J].高分子通报, 2012(1):8.
[17] 沙华, 孙玲, 刘东雷.DPD方法在软物质模拟领域的研究及应用进展[J].材料导报A, 2014, 28(3):117-121.
[18] 潘恒, 张洋, 周茗萱, 等.耗散粒子动力学在高分子领域中的应用[J].胶体与聚合物, 2016(1):42-45.
[19] 吴立明, 张国庆, 刘汉涛.耗散粒子动力学的发展与应用简述[J].科技信息, 2012(9):450.
[20] 王占良.锂离子电池用聚合物电解质应用基础研究[D].天津:天津大学, 2003.