Electrospinning Preparation Of MOFs And Derivative Nanofibers For Supercapacitors

Nanofiber materials are favored by many researchers of high-performance supercapacitors(SCs)electrode materials due to their unique structure,light weight,and large specific surface area.Metal-organic framework(MOFs)materials have the advantages of periodic structure,functional diversity,hierarchical porosity,etc.,this provide sufficient space for the electrochemical reaction of electrode materials,and can be used as sacrificial templates to produce metal-based compound electrode materials with high density.Electrospinning technology can efficiently and controllably prepare a wide range of nano-scale fibers,and has shown great application potential in drug delivery and release,environmentally friendly filter membranes,battery separators,etc.Based on electrospinning technology and combining with other post-treatment methods,this subject develops MOFs and derivative nanofiber electrode materials with high energy storage and stable cycling performance.The main work content is as follows:1.The CNF@Ni-CAT core-shell nanofiber was prepared using carbon nanofibers(CNFs)prepared by electrospinning and high-temperature carbonization as a matrix,and two-dimensional conductive MOFs(Ni-CAT)were grown on the surface of CNFs by a simple hydrothermal synthesis method.The composite nanofibers were prepared into electrodes and tested for their superelectric properties:a specific capacitance of 502.95 F g^-1 was exhibited at a current density of 0.5 A g^-1,and after 5000 cycles,the retention rate of the initial capacitance was 73%;the asymmetric supercapacitor device(ASC)assembled by CNF@Ni-CAT and activated carbon(AC)has an energy density of 18.67 W h kg^-1 at a power density of 297.12 W kg^-1.In addition,CNF@Ni-CAT composite nanofibers have a high mechanical flexibility,after bending tests at various angles,the electrochemical properties have not changed significantly,proving that the composite nanofibers have great application potential in the field of flexible devices.2.Using electrospun polymer-metal ion composite nanofibers as a soft template,zeolite imidazole nanoparticles(ZIF)were grown in situ on the surface of the nanofibers by a solvent method,and then calcined in air to prepare metal oxide hollow tubular nanofiber materials(ZnO HTNs,Co₃O₄ HTNs and ZnCo₂O₄ HTNs),this materials exhibit excellent energy storage performance and cycle stability.Take ZnCo₂O₄ HTNs as a representative:when it is used in the positive electrode of SCs,it exhibits a specific capacity of 181 C g^-1 at a current density of 0.5 A g^-1.After 10,000 cycles of testing,the capacity retention rate reaches 97.42%.In addition,the ASC assembled from ZnCo₂O₄ HTNs and AC showed stable and ultra-high cycle stability.After 20,000cycle tests,the capacity retention rate was 95.38%.After analysis,the excellent cyclic stability of the electrode has a huge relationship with the hollow tubular structure of the material.This synthesis strategy provides a direction for the research of hollow tubular nanofiber structures or long-life electrode materials.In summary,this subject is committed to adopting different synthetic strategies,using MOFs and derivative nanofibers as research objects,to prepare supercapacitor electrode materials with high performance and stable cycling performance.The research results of this topic not only prove the research potential of electrospinning MOFs and derivative nanofiber electrode materials in the field of energy storage,but also provide a direction for the research of long-life supercapacitor electrode materials.