A Critical Review on Materials and Fabrications of Thermally Stable Separators for Lithium‐Ion Batteries

Abstract

Li‐ion batteries nowadays are widely used as energy storage systems owing to their high power and energy densities. However, the safety of Li‐ion batteries has increasingly become a grave concern, and how to effectively mitigate or avoid the thermal runaway of Li‐ion batteries, particularly during fast charging/discharging, is a critical issue. It has been pointed out that among various factors governing the safety of Li‐ion batteries, the thermal stability of separators plays an important role. In this review, a critical discussion is reported on recent research and development of thermally stable separators, including surface modified polyolefin separators, novel polymer separators, inorganic structured separators, and functional smart separators, for improving the safety of Li‐ion batteries, summarizing different techniques, processes, and materials being researched and developed for these separators for lithium‐ion batteries. Finally, suggestions are provided on future directions to develop thermally stable separators with respect to the safety of next‐generation Li‐ion batteries.

“Functional upcycling” of polymer waste towards the design of new materials

“…, phenolic resin and vinyl trimethoxysilane) (Table 2(3, 5)). 159,197 The functionalisation of raw and commercially used PE for lithium-ion separator application has been reviewed, 174,218 and the reported approaches on raw PE can be implemented for waste and commercially used PE materials.…”

“…Various functionalisation strategies of commercially available PE separators can be implemented to improve heat stability and interfacial compatibility (e.g., phenolic resin and vinyl trimethoxysilane) (Table 2(3, 5)). 159,197 The functionalisation of raw and commercially used PE for lithium-ion separator application has been reviewed, 174,218 and the reported approaches on raw PE can be implemented for waste and commercially used PE materials.…”

Biopolymer-based electrospun fibers in electrochemical devices: versatile platform for energy, environment, and health monitoring

“…These structures have lengths and diameters of up to several microns and offer the best physical properties. 166,167 Sheng et al 168 summarized major types of cellulose such as cellulose, nanocellulose, and cellulose derivatives, as well as various methods for the preparation of cellulose-based LIB separators, including electrospinning, force spinning, paper making, solution casting, conventional coating, and phase inversion method, and concluded that the papermaking process could be a good choice for low-cost bulk production. Chen et al 169 presented a detailed study on the advancements in the structural and physical characteristics of nanocellulose in energy storage applications such as Li/Na ion batteries, lithium-sulfur batteries, and supercapacitors.…”

Ionic liquids as potential electrolytes for sodium-ion batteries: an overview

“…An increase in temperature decreases the viscosity of the electrolyte, improving its wettability and mobility of species, and consequently enhances its ionic conductivity. 3,17,18 Moreover, certain attention must be given to the salt selected for the electrolyte (usually based on the same anion of the IL) as well as its concentration. In general, increasing the salt concentration in the medium is detrimental to the transport properties of ILs.…”