Preferential lattice expansion of polypropylene in a trilayer polypropylene/polyethylene/polypropylene microporous separator in Li-ion batteries

Wen Dung Hsu, Po Wei Yang, Hung Yuan Chen, Po Hsien Wu, Pin Chin Wu, Chih Wei Hu, Lakshmanan Saravanan, Yen Fa Liao, Yen Teng Su, Dinesh Bhalothia, Tsan Yao Chen, Chia Chin Chang

研究成果: Article同行評審

摘要

The abnormal lattice expansion of commercial polypropylene (PP)/polyethylene (PE)/polypropylene (PP) separator in lithium-ion battery under different charging current densities was observed by in-situ X-ray diffraction. Significant lattice changes of both PP and PE were found during the low current density charging. The capacity fading and the resistance value of the cell measured at 0.025 C (5th retention, 92%) is unexpectedly larger than that at 1.0 C (5th retention, 97.3%) from the electrochemical impedance spectroscopic data. High-resolution scanning electron microscopy is employed to witness the pore changes of the trilayered membrane. Density functional theory calculations were used to investigate the mechanism responsible for the irregular results. The calculations revealed that the insertion of Li-ion and EC molecule into PP or PE are thermodynamically favourable process which might explain the anomalous significant lattice expansion during the low current density charging. Therefore, designing a new separator material with a more compact crystalline structure or surface modification to reduce the Li insertion during the battery operation is desirable.

原文English
文章編號1929
期刊Scientific reports
11
發行號1
DOIs
出版狀態Published - 2021 十二月

All Science Journal Classification (ASJC) codes

  • General

指紋 深入研究「Preferential lattice expansion of polypropylene in a trilayer polypropylene/polyethylene/polypropylene microporous separator in Li-ion batteries」主題。共同形成了獨特的指紋。

引用此