Study On The Modification And Electrochemical Performance Of Lithium-sulfur Battery Separator

In recent years,with the widespread application and development of electric vehicles and electronic devices,the capacity of traditional lithium-ion batteries has been unable to meet the energy requirements of these electronic devices,so the development of new high-energy-density,long-cycle-life secondary battery systems is imminent.Lithium-sulfur batteries have become a promising energy storage system due to their high energy density and high theoretical specific capacity.Due to severe shuttle effects and the volume expansion of sulfur cathodes,the widespread application of lithium-sulfur batteries faces difficulties and challenges.In this paper,two kinds of organic metal framework?MOF?-derived materials are used to study the coating modification of traditional commercial separator PP.The chemical adsorption of metal oxides and the physical adsorption of carbon materials inhibit the shuttle effect of polysulfides and improve the battery's cycle performance.The organic metal frame ZIF-67 was prepared by a solvothermal method,and the metal oxide tricobalt tetraoxide Co₃O₄ was derived through high-temperature calcination.At the same time,spherical Co₃O₄ was prepared by hydrothermal synthesis,and the prepared Co₃O₄ was characterized and tested by SEM,XPS,BET and other methods.The modification effect of Co₃O₄ with different morphologies on the lithium-sulfur battery separator was investigated.Polysulfide adsorption experiments show that the modified separator can effectively adsorb polysulfides and suppress its"shuttle effect".Electrochemical performance tests show that ZIF-67-derived Co₃O₄ has a better modification effect.At a charge and discharge rate of 0.1 C,the specific discharge capacity of the battery for the first time is as high as1569 m Ahg^-1.After 100 cycles,the specific capacity is maintained at 959.7 m Ahg^-1,and the Coulomb efficiency is above 97%.The organometallic framework ZIF-8 and ZIF-8@PVP were prepared by solvothermal method.ZPC and HCF porous carbons with different pore structures were obtained after high-temperature calcination in an inert atmosphere,and the lithium-sulfur battery separator was modified by ZPC and HCF.Were studied.The study found that at a charge and discharge rate of 0.1 C,the first specific discharge capacity of the battery after HCF porous carbon modified separator was 1485.6m Ahg^-1.After 50 cycles,the specific discharge capacity was still maintained at 972.9m Ahg^-1 which greatly improved lithium.sulfur batteries.electrochemical performance.