Due to the mechanical stability of PP layer,the PP/HDPE double-layer microporous mem brane could be prepared at a higher heat-setting temperatu re than that of PE monolayer membrane.In this work,the effects of heat-se...Due to the mechanical stability of PP layer,the PP/HDPE double-layer microporous mem brane could be prepared at a higher heat-setting temperatu re than that of PE monolayer membrane.In this work,the effects of heat-setting temperature on the pore structure and properties of PP/HDPE dou ble-layer membrane were studied.With the increase of heat-setting temperature from 120℃to 130℃,the length of connecting bridge crystal and crystallinity in the PE layer increase due to the melting of thin lamellae and the stability of connecting bridge structure during heat-setting.The corresponding air permeability,po rosity,wetta bility of liquid electrolyte and mechanical property of the heat-set microporous membrane increase,exhibiting better electrochemical performance.However,when the heat-setting temperature is further increased to 140℃,higher than the melting point of PE resin,some pores are closed since the lamellae and connecting bridges melt and shrink during heat-setting,resulting in a decrease of air permeability and porosity.In contrast,there is negligible change in the PP layer within the above heat-setting temperature region.This study successfully builds the relationship between the stable pore structure and property of microporous membrane during heat-setting,which is helpful to guide the production of high-pe rformance PP/PE/PP lithium batteries separator.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52173033,51773044 and51603047)Research and Development Plan for Key Areas in Guangdong Province(No.2019B090914002)+3 种基金Guangdong Province Science and Technology Plan Project(No.2016A010103030)the Project of Science Foundation of Guangdong Province(No.2021A1515011914)Foshan Science and Technology Innovation Project(No.FS0AA-KJ919-4402-0145)Commissioned development project by Lanzhou Chemical Research Center of Petro China(No.kywx-23-010,2022DJ6315)。
文摘Due to the mechanical stability of PP layer,the PP/HDPE double-layer microporous mem brane could be prepared at a higher heat-setting temperatu re than that of PE monolayer membrane.In this work,the effects of heat-setting temperature on the pore structure and properties of PP/HDPE dou ble-layer membrane were studied.With the increase of heat-setting temperature from 120℃to 130℃,the length of connecting bridge crystal and crystallinity in the PE layer increase due to the melting of thin lamellae and the stability of connecting bridge structure during heat-setting.The corresponding air permeability,po rosity,wetta bility of liquid electrolyte and mechanical property of the heat-set microporous membrane increase,exhibiting better electrochemical performance.However,when the heat-setting temperature is further increased to 140℃,higher than the melting point of PE resin,some pores are closed since the lamellae and connecting bridges melt and shrink during heat-setting,resulting in a decrease of air permeability and porosity.In contrast,there is negligible change in the PP layer within the above heat-setting temperature region.This study successfully builds the relationship between the stable pore structure and property of microporous membrane during heat-setting,which is helpful to guide the production of high-pe rformance PP/PE/PP lithium batteries separator.
