Preparation And Energy Storage Characteristics Of Two-dimensional Sodium Niobate Doped PVDF Composite

In today's society,the demand for energy is increasing day by day and fossil energy is being consumed continuously.There are still many problems to be solved in the development and application of new energy.In the field of energy storage,it is difficult for traditional batteries to charge and discharge rapidly,and the energy storage density of traditional capacitors is low.In this paper,NaNbO₃/PVDF composite films were prepared to prepare composite energy storage materials with the advantages of high dielectric constant of ceramic materials and high breakdown field of polymer materials.In this paper,two-dimensional NaNbO₃ fillers were firstly prepared by two-step molten salt method.The prepared NaNbO₃ was filled into PVDF solution according to different volume ratios,and Na Nb O3/PVDF composite films with volume ratios of 0.5%,1%,1.5%,2%,3%and 4%were prepared by solution method.The composite films were characterized by means of SEM,XRD,infrared spectroscopy,etc.Weibull distribution was used to analyze the breakdown characteristics of composites,dielectric spectrum was used to analyze the dielectric characteristics of composites,and ferroelectric analysis system was used to test the energy storage characteristics of composites.The results show that:for the breakdown characteristics of composites,the breakdown strength of NaNbO₃/PVDF nanocomposites decreased with the increase of the filling amount of NaNbO₃.For the dielectric properties of the composites,the relative dielectric constant of the composites will increase with the increase of the filling amount of NaNbO₃,and the relative dielectric constant will decrease with the increase of the frequency in the whole frequency range.With the increase of frequency,the tangent value of loss Angle of the composite media decreases first and then increases.Under the same electric field,the loss of the composite media increases with the increase of the filling amount of NaNbO₃.The conductivity of the composite media increased with the increase of frequency,and the conductivity of the composite media increased with the increase of the filling amount of NaNbO₃.In the range of 0.5%to 4%of NaNbO₃ filling volume,the energy storage density of NaNbO₃/PVDF composite material increases with the increase of the volume ratio of NaNbO₃ filling volume.However,due to the fact that the material with high doping ratio is not able to withstand breakdown,the material with low ceramic doping ratio can achieve higher energy storage density at high field strength.The energy storage efficiency of the composite film decreases with the increase of the electric field intensity.