材料科学
分离器(采油)
聚烯烃
多孔性
膜
热稳定性
化学工程
离子电导率
复合材料
化学
电极
物理化学
生物化学
物理
工程类
电解质
热力学
图层(电子)
作者
Guoxiang You,Qingsong Liu,Man‐Cheng Long,Guorui Zhu,Gang Wu,Xiuli Wang,Yu‐Zhong Wang
出处
期刊:Small
[Wiley]
日期:2024-03-28
标识
DOI:10.1002/smll.202400980
摘要
Polyolefin separators are the most commonly used separators for lithium batteries; however, they tend to shrink when heated, and their Li+ transference number (t Li+) is low. Metal-organic frameworks (MOFs) are expected to solve the above problems due to their high thermal stability, abundant pore structure, and open metal sites. However, it is difficult to prepare high-porosity MOF-based membranes by conventional membrane preparation methods. In this study, a high-porosity free-standing MOF-based safety separator, denoted the BCM separator, is prepared through a nano-interfacial supramolecular adhesion strategy. The BCM separator has a large specific surface area (450.22 m2 g-1) and porosity (62.0%), a high electrolyte uptake (475 wt%), and can maintain its morphology at 200 °C. The ionic conductivity and t Li+ of the BCM separator are 1.97 and 0.72 mS cm-1, respectively. Li//LiFePO4 cells with BCM separators have a capacity retention rate of 95.07% after 1100 cycles at 5 C, a stable high-temperature cycling performance of 300 cycles at 80 °C, and good capacity retention at -40 °C. Li//NCM811 cells with BCM separators exhibit significantly improved rate performance and cycling performance. Pouch cells with BCM separators can work at 120 °C and have good safety at high temperature.
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