The Development of High-Power LIBs Separators

Abstract

Separators present the crucial functions of separating the positive and negative electrodes due to the free flow of lithium ions through the liquid electrolyte that fills in their open pore. Separators for liquid electrolyte Lithium-ion batteries can be classified into porous polymeric membranes, nonwoven mats, and cellulose separators. When a lithium-ion battery is being overcharged, it releases the heat and results in the inner-short. The polyethylene (PE) separators used here had shut down at around 135°C to cool the exothermal batteries. To enhance the meltdown temperature of the separator, a PE separator was coated with polymers synthesized from various ethylene glycol dimethacrylate monomers. At the same time, nonwoven mats have the potential to be low cost and thermally stable separators. Furthermore, the lithium-ion phosphate/lithium half cell using cellulose separator exhibited stable charge-discharge capability even at 120 °C. This paper presents an overview of the PE and PP membranes of lithium-ion battery separators, discusses how to solve their disadvantages, and reviews the cellulose-based materials developed for potential application in the lithium-ion battery.