Controllable Coating Of Alumina And Boehmite Ceramic On The Surface Of Polyimide Nanofiber Membrane And Its Application As Separator For Lithium Ion Batteries

Since it's inception,lithium ion battery has become one of the most promising green energy sources due to the advantages of high energy density and low environmental pollution.However,gradually,traditional lithium ion batteries have been unable to meet the rapidly increasing social demand of high-rate charge-discharge performance and high-temperature resistance.In the battery structure,the battery separator plays a role as preventing the direct contact of positive and negative electrodes and providing ion transmission channel.The performance of the battery separator is an important determinant of battery performance.Traditional battery separator uses polyolefin as raw material,which has poor electrolyte wettability and poor thermal stability.It is difficult for traditional separator to meet the requirements for improving the high rate charge and discharge performance and high temperature resistance.Therefore,the development of new-type lithium ion battery separators with high thermal stability and high electrolyte wettability is an urgent need in the research field of lithium ion batteries.In this paper,based on the adsorption and complexation effect of nanofiber membranes,we innovatively designed the adsorption complexation alkaline hydrolysis method and chemical vapor deposition method to have alumina and boehmite ceramic coated around polyimide nanofibers.We successfully prepared polyimide/boehmite composite nanofiber membranes and polyimide/alumina composite nanofiber membranes with coaxial structures,and the amount of boehmite coating on the surface of the polyimide nanofiber membranes was adjusted,which will provide a new idea for lithium ion battery separator research.In this paper,the micromorphology,thermal stability,mechanical properties,electrolyte wetting performance,porosity,and liquid absorption of the composite nanofiber membrane were tested through various characterization methods,and the performance of the composite membranes as lithium ion battery separators were studied.The results show that both polyimide/boehmite composite nanofiber membrane and polyimide/alumina composite nanofiber membrane have even fiber morphology,excellen thermal stability and electrolyte wettability;comparing with Celgard membrane,the polyimide/boehmite composite nanofiber membrane and the polyimide/alumina composite nanofiber membrane have higher ionic conductivity,which can effectively improve the battery's discharge specific capacity,high rate charge/discharge performance and safty.