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Download fileBinder-Free, Thin-Film Ceramic-Coated Separators for Improved Safety of Lithium-Ion Batteries
journal contribution
posted on 2021-02-03, 18:43 authored by Ashish Gogia, Yuxing Wang, Amarendra K. Rai, Rabi Bhattacharya, Guru Subramanyam, Jitendra KumarSeparators play a
crucial role in ensuring the safety of lithium-ion
batteries (LIBs). Commercial polyolefin-based separators such as polyethylene
(PE) still possess serious safety risks under abuse conditions because
of their poor thermal stability. In this work, a novel type of binder-free,
thin ceramic-coated separators with superior safety characteristics
is demonstrated. A thin layer of alumina (Al2O3) is coated on commercial PE separators using the electron-beam physical
vapor deposition (EB-PVD) technique. Scanning electron microscopy
(SEM), contact angle, impedance spectroscopy, and adhesion test techniques
were employed to evaluate structure–property correlations.
When compared to commercial slurry-coated separators, the EB-PVD-coated
separators display (i) higher thermal stability, (ii) stronger ceramic–polymer
adhesion, and (iii) competitive electrochemical performance of full
LIB cells. Thermal stability, in terms of improved shutdown and breakdown
characteristics of the separator, was studied using the in situ impedance
technique up to 190 °C. In addition, the improved adhesion of
the ceramic layer deposited on the PE separator was studied following
the tape adhesion strength test. We prove that the thin (binder-free)
ceramic layer coated by EB-PVD is far more effective in improving
separator safety than those made using the conventional thick slurry
coating.
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Keywords
slurry coatingabuse conditionssafety characteristicsScanning electron microscopyEB-PVD-coated separators displayadhesion test techniquesbreakdown characteristicsPE separatorAl 2 O 3PE separatorsLithium-Ion Batteries Separatorselectrochemical performanceimpedance spectroscopynovel typeCommercial polyolefin-based separatorstape adhesion strength testThermal stabilitybinder-freevapor depositionThin-Film Ceramic-Coated Separatorssafety risksSEMseparator safetyceramic-coated separatorsLIB cellsimpedance techniqueslurry-coated separatorslithium-ion batteries