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.
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