678 / 2022-03-31 14:25:52

Energy storage properties of PVDF composites with different calcination temperature BaTiO3

energy storage,dielectric properties,Polymer

Purpose/Aim

The low energy storage density caused by low permittivity of the dielectric film has become a barrier for the further development of film capacitor. Introducing high-permittivity nanofillers (eg. BaTiO₃) into the polymer matrix turns out to be a promising way of improving dielectric properties. Therefore, PVDF composites were fabricated to demonstrate the optimized energy storage properties with different calcination temperature BaTiO₃ (BT). 

Experimental/Modeling methods

BT was calcined in a muffle furnace with different temperature (200 ^oC~800 ^oC), and silane coupling agent KH550 was selected to modify the surface of the calcined BT nanoparticles. Finally, the BT/PVDF and BT@KH550/PVDF composite films were prepared by solution casting method. 

Results/discussion

The BT/PVDF composite film exhibited slightly changed permittivity and significantly improved breakdown strength with different calcination temperature of BT. BT calcined at 400 ^oC was found as the optimized filler, which obtained the highest breakdown strength of 441 MV/m with 5 wt% filler content, and was further improved to 470 MV/m using KH550 surface modification of BT. Thus, the BT@KH550/PVDF composite film (BT calcined at 400 ^oC) showed the highest energy density of 7.9 J/cm³.

Conclusions

The energy density of the composites could be significantly influenced by calcination temperature and BT, and proper surface modification of fillers was proved to be an effective way to further improve the energy storage performance of dielectric composite film.