Abstract Thermally induced phase separation (TIPS) is used to prepare polyethylene (PE) micro-porous membrane, consisting of melt blending, fast cooling, stretching and extracting process, which determine the pore-structure of the PE membrane. In this study, we tried to extract PE/liquid paraffin (LP) oil membrane to obtain PE porous membrane by n-hexane (n-PE) and dichloromethane (d-PE). The n-PE membrane would shrink by 10% for extractant volatilizing, less than 15% of the d-PE membrane after the extraction. These PE membranes were applied into symmetrical cells and LiCoO2/Li cells. As a result, the LiCoO2/Li cell based on n-PE separator exhibited better capacity retention (98%) than d-PE separator (91%) after 80 cycles at a current density of 1C rate for higher ionic conductivity. And the LiCoO2/Li cell with d-PE separator had higher capacity at 2C and 3C, it could be attributed to stronger interaction between solvent and wall of d-PE separator with the smaller and curved pore. In addition, the method that electrochemical impedance spectroscopy (EIS) technique carried out with cyclic voltammetry (CV) and charge-discharge curves is successfully applied to monitor the variety of impedance during the cycles, which is helpful to explore the mechanism of capacity attenuation.

中文翻译：

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通过提取工艺调整锂离子电池聚乙烯（PE）隔膜的形貌

摘要 热致相分离(TIPS)用于制备聚乙烯(PE)微孔膜，包括熔融共混、快速冷却、拉伸和提取过程，这些过程决定了PE膜的孔结构。在本研究中，我们尝试通过正己烷（n-PE）和二氯甲烷（d-PE）提取PE/液体石蜡（LP）油膜以获得PE多孔膜。n-PE 膜会因萃取剂挥发而收缩 10%，小于萃取后 d-PE 膜的 15%。这些 PE 膜被应用于对称电池和 LiCoO2/Li 电池。因此，在 1C 倍率的电流密度下循环 80 次后，基于 n-PE 隔膜的 LiCoO2/Li 电池表现出比 d-PE 隔膜更好的容量保持率（98%），以获得更高的离子电导率。而带有 d-PE 隔膜的 LiCoO2/Li 电池在 2C 和 3C 下具有更高的容量，这可能是由于溶剂与 d-PE 隔膜的壁之间的相互作用更强，具有更小和弯曲的孔隙。此外，电化学阻抗谱（EIS）技术结合循环伏安法（CV）和充放电曲线的方法成功应用于监测循环过程中阻抗的变化，有助于探索容量衰减的机制。