The Research Of Morphology Control And Electrochemical Performance Of Carbides Derived From Conjugated Microporous Polymers

Conjugated microporous polymer?CMP?is a kind of microporous organic polymer?MOP?with large specific surface area,tuned porous structure and good chemical stability,moreover,it is more and more widely used in supercapacitors,catalysis,gas adsorption and storage,etc.Unlike those of conventional porous materials,the pore structure and morphology of CMP could be commendably tuned by changing the monomers in the CMP network.Using 1,3,5-triethynylbenzene and 1,5-dibromonaphthalene as monomers,the conjugated microporous polymer?CMP?is synthesized by Pd?0?/Cu?I?-catalyzed Sonogashira-Hagihara cross-coupling polycondensation,and the resulting CMP has unique tubular structure and porous structure.In particular,the nanotube-like structure can be well maintained during high-temperature pyrolysis because of the 3D interlinked carbon skeleton of CMP nanotube.So,the Porous carbon nanotube?PCNT?can be undoubtedly obtained by direct pyrolysis of CMP nanotube.The CMP has numerous active sites?C?C?for binding of metallic ions,so that Mn O can be further filled into the PCNT to obtain the composite material of Mn O and PCNT?Mn O-PCNT?.Through the SEM,TEM,TEM-EDX element mapping and specific surface area test,proved that Mn O nanoparticles enter into the PCNT and form a good composite material,further by electrochemical performance test,the specific capacity of Mn O-PCNT is 161 m Ah·g^-1 at 30 C,after 300 cycles at 1 C is still as high as 573 m Ah·g^-1,the results show that Mn O-PCNT has good rate performance and cycling stability.The nitrogen-containing conjugated microporous polymer?NCMP?is synthesized by palladium-catalyzed Sonogashira-Hagihara crosscoupling condensation of1,3,5-triethynylbenzene and bis?4-bromophenyl?amine.The resulting NCMP sample exhibits good chemical and thermal stability due to its rigid structure,nitrogen-containing porous carbon nanoparticle?NPCN?can be obtained by direct pyrolysis of NCMP at high temperature,the particle size and morphology of NPCN have not changed.NPCN is used as anode material for lithium ion battery,and through electrochemical testing,The results show that the specific capacity of NPCN is lower(²16.0 m Ah·g^-1).Activation of NPCN by KOH with high temperature pyrolysis,and the activated nitrogen-containing porous carbon nanoparticle?NPCN-KOH?is obtained,the specific surface area of NPCN-KOH is 1845 m²·g^-1,and the specific surface area ofNPCN is 418 m²·g^-1,NPCN-KOH shows much larger specific surface area.After 600 cycles,NPCN-KOH at a current rate of 1 C with the charge capacity of 527 m Ah·g^-1,and the capacity retention ratio is 97.6%,it shows excellent cycling performance.In the process of synthesizing CMP,the reaction solvent not only has an important influence on the pore structure of the material,but also affects the morphology of CMP,two kinds of nitrogen-containing conjugated microporous polymers?NCMPs?are synthesized by using toluene and 1,4-dioxane as solvents,1,3,5-triethynylbenzene and bis?4-bromophenyl?amine as monomers.The results of SEM and BET show that the two kinds of materials have different morphologies and pore structures,and then affect their electrochemical properties.