Preparation And Application Of Metal-Organic Frameworks Derived Carbon Materials

Metal-organic frameworks(MOFs)are a type of porous hybrids that formed by connecting metal or metal cluster centers with multidentate organic ligands.Its structure,pores and functionality can be easily adjusted by changing the kinds of metal centers,organic ligands and post-synthetic modification.At the same time,many researches have proved that using MOFs as sacrificial templates can obtain a large number of porous carbon materials with various structures.The derivatized carbon materials prepared by careful calcination of MOFs possess many advantages including large specific surface areas,hierarchical porous structures and abundant active sites.Especially,by modifying the precursor(MOFs),metal/metal oxide,heteroatoms and other nanao materials can be introduced into the porous carbon.In other words,functional carbon materials can be rapidly fabricated by reasonably designing the synthesis steps and then applied in specific fields.Therefore,this paper focus on using MOFs as precursors to preparing functionalized porous carbon materials,while exploring their applications in different fields.(1)In order to solve the shuttle effect caused by polysulfides present in lithium-sulfur batteries,a membrane modification layer with physical and chemical barrier properties was prepared and its influence in battery was also studied.A small amount of iron acetylacetonate was used to modify ZIF-8 as a precursor template,and a porous carbon material doped with iron atoms was synthesized under high temperature calcination,which was coated on the surface of the battery separator by scraping to obtain a modified separator.The experimental results showed that this design improved the utilization rate of the positive electrode active sulfur material,and the battery with good cycle stability and high rate performance is obtained.At a current density of 1 C,the specific discharge capacity of the battery in the first cycle was as high as 1150.7 mAhg-1.After 150 cycles,the reversible specific capacity can be maintained at 692.2 mAhg-1 and the coulomb efficiency was basically maintained at 100%.Reached 411.4 mAhg-1.Furthermore,the specific capacity can reach 411.4 mAhg-1 even at a high rate of 4 C.(2)On the basis of the previous experiment,a porous carbon material co-doped with iron nanoparticles and carbon nanotubes was quickly prepared by using the pores of ZIF-8 to bind more Fe(acac)3 as a modified MOF precursor.The specific growth mechanism of iron nanoparticles and carbon nanotubes was explored.These porous carbon materials with large specific surface area,multiple action sites and magnetic properties have good dielectric and magnetic permeability properties.The experimental results exhibited that the synthetic method which integrating magnetic particles and carbon materials with certain conductivity in the three-dimensional network structure can effectively improve the electromagnetic shielding performance.The above research has provided new ideas for the preparation and application of MOFs-derived carbon materials to a certain extent.