Research On Preparation And Energy Storage Performance Of Ba_0.6Sr_0.4TiO₃ Nanofibers Network/PVDF Multilayer Composites With High Energy Storage

The development of advanced energy storage technologies,along with the global increasing demand for energy supply and the rapid consumption of fossil fuels,is imperative for the last decade.Inorganic-polymer nanocomposites,which are flexible,have shown tremendous potential in energy storage applications due to their ultra-high charging-discharging capability.The addition of nanofibers with high aspect radio enhanced dielectric constant and energy density of polymer nanocomposites,compared with the nanoparticles.However,the application of composites is limited by its lower energy storage densities.In this paper,a unique sandwich structure and fiber network was fabricated using Ba_0.6Sr_0.4Ti₃ nanofibers and P?VDF-HFP?powder as the main materials.The sandwich structure,making the fragile filling ceramic nanofibers flexible,enhances the mechanical strength and breakdown strength of composite effectively.Meanwhile,due to the dispersion of local electric field,the fiber network with high aspect ratio can withstand higher breakdown strength,leading to a high energy storage density and high discharge efficiency.The main research contents are as follows:The promoted Maxwell–Garnet model was used to study the relationship between the dielectric constant of the composite with nanofiber-filling and the aspect ratio,the volume fraction of the filler et al.It revealed that increasing the volume fraction of the filler is beneficial to the increase of the dielectric constant of the composite.On the other hand,when the filling fibers are randomly distributed,the dielectric constant of the composite will increase with raising the aspect ratio of the fiber;However,the aspect ratio of the fiber which is perpendicular to the direction of the electric field,has a limited effect on the dielectric constant of the composite.The interconnection structure of nanofibers network?80 aspect ratio?was fabricated by electrospinning and peeling sintering.The sandwich structure composite with loading BSTnws network was prepared by dropping coating process.The results show that the dielectric constant of the composite reaches 24.8,which is much higher than that of pure P?VDF-HFP?film 10.4.The breakdown strength of the composite reaches 3000 kV/cm,resulting in an extremely high energy storage density of 9.46J/cm³?twice the energy storage density of pure P?VDF-HFP?film?and an enhanced energy storage efficiency of 66.8%.This research shows superiority in solving the contradiction between high dielectric constant and high breakdown strength,opening up a new avenue for the structural adjustment of nanocomposites.