Effect of SiO₂ content on performance of polypropylene separator for lithium‐ion batteries

Abstract

Composite separators are prepared by introducing SiO2 nanoparticles on both sides of polypropylene separator with various SiO2 contents through a dip‐coating process, where polyvinylidene fluoride‐hexafluoropropylene is used as binder. Coated layers have highly porous structure, which is quantitatively analyzed by air permeability. Compared to pristine separator, composite separators show significant lower Gurley value, reduced thermal shrinkage, higher liquid electrolyte uptake, better mechanical properties, and better cell performance such as discharge C‐rate capability and cycle performance. The influence of SiO2 content on these properties is also studied, and the best SiO2 content is given. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41156.

Preparation of 4A zeolite coated polypropylene membrane for lithium‐ion batteries separator

“…This can be due to the presence of higher heat‐resistant 4A zeolite particles on the separator surface, as it was also in observed surface SEM images of the coated separator shown in Figure . The same observations were also reported in the other studies where other heat‐resistant materials were coated . Additionally, as the casing solution's 4A zeolite content increases, thicker coated layers were provided as shown in the cross‐sectional SEM images of the coated separator as shown in Figure where resulted in considerable reduction of their thermal shrinkages.…”

“…The neat separator's liquid electrolyte uptake depends only on its porosity. However, the coated separators' liquid electrolyte uptakes depend not only on the trapped electrolyte in the separators' substrate but also on the electrolyte uptake within the coated layer porous network …”

“…Both reduced contact angles and increased porosities of the coated separators confirm their increased electrolyte uptake obtained due to the coated layer hydrophilicity and porous structure . At the higher 4A zeolite coatings on the neat separator's top surface, higher porous structure with enhanced liquid electrolyte uptakes is obtained.…”

Enhanced wettability and thermal stability of polypropylene separators by organic–inorganic coating layer for lithium‐ion batteries

“…The weight change of modified separators compared with bare PP separators was calculated by the equation: where M and M 0 are the weight of the separators before and after modification, respectively …”

Imidazolium‐functionalized norbornene ionic liquid block copolymer and silica composite electrolyte membranes for lithium‐ion batteries

“…Another way to improve the ionic conductivity is to form a composite polymer electrolyte by the addition of ceramic packing. The addition of these nanoparticles can not only improve the microstructure of the polymer but also increase the separation degree of lithium and ultimately improve the ionic conductivity . For example, Zhu et al .…”