Preparation Of Porous Carbon Fibers Based On Electrospinning Technology And Its Capacitive Performance

As a new energy storage device,supercapacitors have attracted widespread attention due to their irreplaceable advantages such as high power density,long cycle life,and safety and pollution-free.The electrode material is a key factor in the performance of supercapacitors.Therefore,searching for electrode materials with good performance is the focus of supercapacitor research.The main work here is to use a mixture of polyacrylonil and other inorganic salts as the precursor solution,to synthesize a porous structure carbon fiber electrode material by electrostatic spinning method,to convert its electrostatic supercapacitor and to study its capacitance characteristics.The details are as follows:1. Nitrogen-enriched hierarchical porous carbon nanofibers?HPCNFs?with superior capacitance and outstanding mechanical strength are facilely fabricated by electrospinning of Polyacrylonitrile/Magnesium acetate?PAN/Mg?OAc?₂?precursor,preoxidation and carbonization of composite nanofibers,which use PAN as carbon source and Mg?OAc?₂as precursor of Mg O template.The introduction of Mg?OAc?₂not only forms the hierarchical porosity with a large specific surface area,but also improve the thermoplasticity and mechanically flexibility of HPCNFs.Under two-electrode configuration,the as-prepared HPCNFs exhibit a high specific capacitance of 263 F g^-1at a current density of 1.0Ag^-1,good rate capability with a capacitance retention of 157 F g^-1up to the current density of 100 A g^-1and excellent cycling stability of 94.2%over 10000 cycles in 6.0 M KOH electrolyte owing to the synergistic effect of the hierarchical porosity and high nitrogen-enriched level of HPCNFs.Moreover,the flexibility test of HPCNFs demonstrates the excellent mechanical flexibility of HPCNFs,indicating their promising application in flexible energy storage devices.2. Large effective surface area and high electrical conductivity are critical for the high-performance carbon-based electrode materials for supercapacitors.Herein,three-dimensional?3D?cross-linked nitrogen-enriched porous carbon nanofibers?C-CNFs?are facilely prepared by electrospinning of polyacrylonitrile/zinc chloride?PAN/Zn Cl₂?precursor,preoxidation and carbonization of the electrospun composite nanofibers.The Zn Cl₂additive makes effects of both cross-linking and pore-forming electrospun carbon nanofibers simultaneously.The as-prepared C-CNFs exhibits a good rate capability of about 60%with current densities ranging from 1 to 60 A g^-1,excellent cycling stability of 97.3%over 60,000cycles in alkaline electrolyte,and a high specific capacitance of 214 F g^-1at 1.0 A g^-1in acidic electrolyte,all of which are significantly superior to the non-cross-linked carbon nanofibers.The significant enhancement of capacitive performance of C-CNFs can be attributed the synergistic effect of its enlarged specific surface area for more charge accumulation and cross-linked architecture that enable the electrons to fast transfer throughout the fibrous membrane.Moreover,the 3D cross-linked carbon nanofiber networks is expected to be a candidate building block of composite electrodes fabrication for the promising applications in other systems that involve a continuous pathway for electron transport,such as metal ion batteries and catalysis.