Lithium-ion batteries have attracted extensive attention as a power source for portable electronic products

new energy vehicles

power storage equipment and other products. Lithium-ion batteries are composed of four parts: the anode (negative electrode)

cathode (positive electrode)

separator and electrolyte. Although the separator does not directly participate in the electrochemical reaction in lithium-ion batteries

as an important part of lithium-ion batteries

its properties greatly affect the performance of lithium-ion batteries. At present

polyolefin is still the most widely used and commercially successful separator material for lithium-ion battery

while because of its poor electrolyte wettability and thermal stability

the electrical properties and safety of lithium-ion batteries are reduced

so modification has become an important way to improve the performance and promotion of polyolefin separator materials. This paper summarizes the latest research progress on modification of polyolefin-based separators in the past five years through constructing of multilayer film method

surface coating technology and layer-by-layer self-assembly deposition technique. Finally

it is proposed that the thermal stability and electrochemical performance of polyolefin separators are still the key points of future research

and new separator materials are prospected.