Polyphenols assisted silica coating on polypropylene separators with improved wettability and heat‐resistance for lithium‐ion batteries

Abstract

The separator, as one of the essential components for lithium‐ion batteries (LIBs), has garnered considerable attention because of its significant role in battery performance. Here, an in‐situ coating method to promote the wettability and thermal‐stability of polypropylene (PP) separators was reported. The separator was first dip‐coated with phenolic compound based on biologically inspired surface modification. Then silica layers were in‐situ formed on the separator via a sol–gel process of silicate solution, so that an inorganic–organic hybrid layer was coated on PP separators without the need of any polymer binders. Besides, this method hardly increases the film thickness or sacrifices microporous structure of the pristine separator. Due to the introduction of hybrid layers, the resulted separators showed excellent dimensional thermostability, as the thermal shrinkage was only 20% at 150 °C while that of the bare separator was about 80%. Meanwhile, electrochemical performances of cells with the modified separator were obviously improved, especially the rate performance. At the charge/discharge current density of 5 C, cells with PP separators nearly lost all the capacity, but the modified separator still held 45.7% of the discharge capacity at 0.2 C. This facile yet effective method has great application prospects in the preparation of ceramic‐coated separators. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47277.

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

“…There are several ways to overcome these limitations of polyolefin membrane separators; for instance, their surface modification by chemical grafting, E‐beam treatment, or plasma treatments . Another modification method of the polyolefin separators is to coat them with inorganic and/or organic particles . Various types inorganic materials including different zeolites [melt flow index (MFI) and NaA] have been coated on different polymeric membranes.…”

Amino‐Functionalized Al2O3 Particles Coating Separator with Excellent Lithium‐Ion Transport Properties for High‐Power Density Lithium‐Ion Batteries

“…This result is consistent with previous reports, in which the polar coating layers could lead to the decrease in interfacial resistance. [ 34–36 ] The introduction of polar modification layers could improve the wettability with the polar solvent and enhance the close contact between electrodes and separator, which could contribute to the migration of lithium ion and decrease in the interfacial resistance.…”

Improvement of PAN separator properties using PVA/malonic acid by electrospinning in lithium ion‐batteries

“…Probably, the observed changes in the blend peaks are related to PVA and MA effects on the blended polymer. 30,33,34 For all separators, the absorption peak at 2,244 cm −1 corresponds to the stretching vibration of the nitrile group. 14 Sharp intense absorptions at 2,932 and 1,452 cm −1 can be assigned to CH asymmetric and symmetric stretching, respectively, these two peaks are the most characteristic peaks of pure PAN.…”