Research On Preparation And Performance Of High-end Lithium-ion Battery Separator

Lithium-ion batteries have played an important role in daily life and still have a good development prospect in the next few decades.Separator is an important part of lithium-ion battery,but most of the current commercial separators have disadvantages such as poor electrolyte affinity,low porosity,and non-renewable raw materials,which limit their application in large-scale energy storage equipment.Therefore,the research and development of separators with suitable porosity,better wettability,and renewable raw materials are the focus of the researchers'work.In this paper,BC is used as the raw material of the separator,and high-performance separator is prepared by TEMPO oxidation method or in-situ growth method and applied in lithium-ion batteries.The main research contents are as follows:(1)In the TEMPO/NaBr/NaClO oxidation system,separators with different porosities are prepared by controlling the amount of oxidant.When the amount of oxidant is 8 mmol,the TOBC separator shows a porosity of 65%.In addition,the TOBC8 separator exhibits good wettability and thermal dimensional stability,with an ionic conductivity of 0.388 m S cm^-1.(2)Porous ZIF-67 was synthesized on BC nanofibers by in-situ growth method,and the prepared BC/ZIF-67 composite separator showed better electrolyte retention ability.At the same time,the BC/ZIF-67 separator has good thermal dimensional stability and will not shrink at 180°C.The volume resistance of the BC/ZIF-67separator is 4.46?,the ion conductivity is 0.837 m S cm^-1,and the lithium-ion transfer number can reach 0.543.(3)In order to explore the application of TOBC8 and BC/ZIF-67 separators in lithium-ion batteries,they were assembled into CR2032 batteries to analyze the electrochemical performance of lithium-ion batteries.The first discharge capacity of lithium-ion batteries using TOBC8 or BC/ZIF-67 separators is 4.08%or 6.12%higher than those of lithium-ion batteries using PP separators,respectively.After 100 cycles,the capacity retention rates of lithium-ion batteries using PP,TOBC8,and BC/ZIF-67separators were 86.94%,89.87%and 91.41%,respectively.