Preparation And Energystorage Properties Of Fluorine-containing Polyurea Composite Films

In recent years,with the rapid development of electronic power systems,capacitors with physical and electrostatic energy storage mechanisms have high power density and rapid charging and discharging speeds,making capacitors an important energy storage device.As the core component of a capacitor,energy storage dielectric materials need to have ultra-high discharge energy density and charge and discharge efficiency.The linear dielectric polyurea polymer has high dipole moment and high dipole density,and can have a high dielectric constant while maintaining low dielectric loss,so as to achieve high energy storage density,and can be used as a high-performance medium for capacitor energy storage Preferred materials.In this paper,the molecular structure of polyurea polymer is modified,and the electronegative F atom is added to increase the dipole moment and dipole density of the polymer,thereby improving the dielectric constant and energy storage performance of the polymer.Fluorine-containing polyurea film(F-Ar PU)is prepared by using solution polymerization method with two diamines and isocyanate in different proportions.The film structure is dense under the scanning electron microscope observation,and it is stable before 330?under the thermal weight loss test.When the diamine content is 7.5%,the degree of polymerization of polyurea reaches the maximum,the maximum tensile strength of the film can reach 230.79MPa,the dielectric constant at 100Hz is 5.94,and the energy storage density at 440 MV/m is 4.33J/cm³.Properly increasing the dipole moment and dipole density of the polyurea polymer can increase the dielectric constant and energy storage density.Then adopt the in-situ polymerization method,take the polymer film as the matrix,doped two-dimensional conductive Ti₃C₂T_xMXene particles and ceramic PZT particles to prepare Ti₃C₂T_xMXene/F-Ar PU film and PZT/F-Ar PU film.Two-dimensional conductive Ti₃C₂T_xMXene particles were prepared by etching Ti₃Al C₂ using selective low-intensity delamination(MILD)method.XRD and Raman spectra showed that the vibration peaks of Al atoms disappeared after etching,and Ti3C2Tx MXene showed obvious delamination under the scanning electron microscope,showing an"accordion"structure.While maintaining the excellent mechanical properties of the basic film,when the doping amount of Ti₃C₂T_xMXene is1%,the dielectric constant can reach 11.2,which is about twice that of the basic sample.When the doping amount is 0.50%,the maximum energy storage density can reach 4.749J/cm³.Doping Ti₃C₂T_xMXene utilizes the electroosmotic behavior between conductive particles and fluorine-containing polyurea polymer and the polarization effect between the two-phase interface to increase the dielectric constant of the composite film before the percolation value,while keeping it low The dielectric loss.The PZT was prepared by the sol-gel method,and the peaks were matched under the XRD characterization,and it was a perovskite structure.When the doping amount is 5%,the dielectric constant of the PZT/F-Ar PU film can reach about 7.1,and when the PZT content is 2%,the maximum energy storage density at this time is 5.04J/cm³.The addition of high dielectric constant ceramic PZT particles has a gradual increase in the dielectric constant of the composite film,and can increase the energy storage density.The fluorine-containing polyurea series films prepared in this paper have excellent mechanical properties,high thermal stability,dielectric properties,and energy storage properties,which broaden the development of linear dielectric films.This research provides a way to improve the dielectric properties of polymer composite dielectrics.A novel,simple,and effective approach has been developed,which has broad application prospects for the energy storage of dielectric capacitors.