Role of Separator Surface Polarity in Boosting the Lithium-Ion Transport Property for a Lithium-Based Battery

Abstract

The separator is a significant safety component inside the lithium-based battery. To design a higher-power-density system, a functional separator has attracted more attention. In our study, vinyl trimethoxysilane (VTMS) has been directly grafted onto a polyethylene (PE) separator by γ-irradiation. We have evaluated the performance of a PE separator grafted with VTMS (PE-g-SiH) and its basic hydrolysis separator (PE-g-SiO) in detail and have discussed the role of separator surface polarity in the ion transport process. The consequence shows that the lithium-ion transference number of the PE-g-SiO separator is 0.38, superior than 0.27 of a pure PE separator and 0.29 of a PE-g-SiH separator. It can be a reason that the LiCoO 2 /Li cell with a PE-g-SiO separator shows excellent cycle stability and rate performance. Furthermore, in the case of a PE-g-SiO separator, the Li/Li symmetric model possesses the lowest activation energy of 55.2 kJ mol −1 , indicating that lithium ions migrate easily at the interface of electrodes and a separator filled with liquid electrolyte. It is attributed to the improved interaction between the separator wall and solvent, which is in favor of lithium-ion-selective transport. Hence, separator functionalization is expected to enhance the battery performance further.

Lithium Ion Battery Anode of Mesocrystalline CoTiO3/TiO2 Nanocomposite with Extremely Enhanced Capacity

“…The other is the mesocrystal effect, as illustrated in Figure . The mesocrystal is constructed from oriented nanocrystals, in which there are two kinds of Li + migration passages in the mesocrystalline materials. − One is in the crystal bulk, which is a relatively slow migration passage. CoTiO 3 has a layered structure, and the crystal bulk passage corresponds to the interlayer space (Figure b).…”

Tissue paper-based composite separator using nano-SiO2 hybrid crosslinked polymer electrolyte as coating layer for lithium ion battery with superior security and cycle stability

“…These results can be attributed to hydrophilicity of tissue paper substrate and strong polarity provided by abundant amines in hyperbranched PEI, which can improve electrolyte a nity with separator and be helpful for electrolyte adsorption (Sheng et al, 2021). On the other hand, the incorporation of crosslinking agent at an appropriate content can regulate the formation of interconnected pore structure but produce negligible effect on porosity, which can make the adsorbed electrolyte in ltrate and diffuse in separator quickly (Sheng et al, 2021). However, deeply crosslinking can hinder the penetration of electrolyte and result in attenuation of wettability, which is mainly related to the reduction of porosity as displayed in Table 1.…”

“…Compared with Celgard 2400 and CS(1:0) separator, the lowest contact angle was obtained for CS(10:1) separator no matter at initial contact or after 20 S. As the crosslinking degree increased, there were complete opposite trends observed between contact angle and immersion-height, indicating coincident wettability results. These results can be attributed to hydrophilicity of tissue paper substrate and strong polarity provided by abundant amines in hyperbranched PEI, which can improve electrolyte a nity with separator and be helpful for electrolyte adsorption (Sheng et al, 2021). On the other hand, the incorporation of crosslinking agent at an appropriate content can regulate the formation of interconnected pore structure but produce negligible effect on porosity, which can make the adsorbed electrolyte in ltrate and diffuse in separator quickly (Sheng et al, 2021).…”

Hexagonal Boron Nitride-Coated Polyimide Ion Track Etched Separator with Enhanced Thermal Conductivity and High-Temperature Stability for Lithium-Ion Batteries

“…Tremendous approaches have widely been applied to improve the thermal stability of separators to suppress the thermal runaway of LIBs. One possible way is to fabricate ceramic composite membranes, such as directly coating ceramics (Al 2 O 3 , , SiO 2 , − etc. ), promoting the in situ growth of a thermal insulation layer − on the surface of commercial separators, or embedding ceramic nanoparticles into polymeric materials .…”