Effects of Coated Separator Surface Morphology on Electrolyte Interfacial Wettability and Corresponding Li–Ion Battery Performance

Abstract

In order to study the effect of interfacial wettability of separator on electrochemical properties for lithium–ion batteries, two different kinds of polyvinylidene fluoride-hexafluoropropylene (PVDF–HFP) solution are prepared and used to coat onto a polypropylene (PP) microporous membrane. It is found that the cell performance of a coated separator using aqueous slurry (WPS) is better than that of the coated separator using acetone (APS) as the solvent. The separator with flat and pyknotic surface (PP and APS) has a strong polar action with the electrolyte, where the polar part is more than 80%. To the contrary, the WPS has a roughness surface and when the PVDF–HFP particles accumulate loose, it makes the apolar part plays a dominate role in surface free energy; the dispersive energy reaches to 40.17 mJ m−2. The WPS has the lowest immersion free energy, 31.9 mJ m−2 with the electrolyte, and this will accelerate electrolyte infiltration to the separator. The loose particle accumulation also increases the electrolyte weight uptake and interfacial wettability velocity, which plays a crucial role in improving the cell performance such as the ionic conductivity, discharge capacity and the C-rate capability.

Partially Neutralized Polyacrylic Acid as an Efficient Binder for Aqueous Ceramic‐Coated Separators for Lithium‐Ion Batteries

“…This shows that its thin and even coating does not impede the transportation of Li+ ion. In general, low Gurley value is preferred as it indicates that the CCS has high porosity and low tortuosity which equates to short lithium‐ion pathway within the CCS during charging and discharging [29] …”

“…In general, low Gurley value is preferred as it indicates that the CCS has high porosity and low tortuosity which equates to short lithium-ion pathway within the CCS during charging and discharging. [29] In Figure 1 (c), the X-ray diffraction (XRD) pattern of CCSÀ PnÀ PAA shows that alumina processed with PnÀ PAA. The crystalline peaks match well with the corundum α-Al2O3 (PDF# 00-046-1212).…”

Multifunctional Electrolyte Additive for High-Nickel LiNi0.8Co0.1Mn0.1O2 Cathodes of Lithium-Metal Batteries

“…The wettability of different electrolytes can be assessed by the magnitude of the contact angle on the separator. − The smaller the contact angle, the easier it is to disperse on the separator and contact more area, which provide more passing area for lithium ions. When the electrolyte drips onto the surface of the separator, it can quickly diffuse to the membrane surface.…”

Pristine and Modified Porous Membranes for Zinc Slurry–Air Flow Battery

“…The pore sizes of the different membranes (Table 1) are sub-micrometric, thus the zinc particles are about three orders of magnitude larger, indicating that there is no risk of metallic zinc crossover in the RFB. [41,42] Liquid electrolyte uptake: The wettability of the membranes with electrolyte affect both electrolyte filling time and the ability to retain the electrolyte solution, thus affecting the overall performance of the battery [43,44]. The wettability of a membrane, usually investigated by contact angle measurement, depends on various parameters, such as the chemical affinity between the membrane surface and the electrolyte, porosity (in the case of porous membranes), surface roughness and viscosity of the liquid electrolyte [45].…”