The ceramic-polymer composites are attracted many researchers attention to using as energy storage. The purpose to get both high breakdown field and high polarization. It is very important to use the high dielectric material as a filler in the polymer matrix to obtain both properties. In many research, ferroelectric fillers like BaTiO₃, PbZrO₃, BaSrTiO₃ have been widely used due to their high dielectric performance [1]. One of the promising materials in this area is CCTO due to showing dielectric constant up to 10⁵ [2-3] The CCTO performance as an energy storage is limited due to low breakdown field and high energy loss. One of the acceptable ways to address this problem is making a composite with a polymer to enhance breakdown field. The ferroelectric polymer like PVDF exhibits high dielectric constant while keep breakdown field high [4-5].

The effect of the SiO₂ coating layer and CCTO concentration mixed with PVDF has been studied. The polymer based composites of PVDF/SiO₂/CCTO were made by a spin coating process, in which DMF was used as the solvent. The CCTO powders were coated by SiO₂ using sol-gel method. The P-E loop test was conducted to measure the energy storage of different composites. The results show an increase in breakdown field while the P-E loop becomes slimmer by making a composite with SiO₂. The polarization increased, due to enhancement in the dielectric constant of the composites because of a good connection between matrix and filler made by the additive. The microstructure was studied by using SEM pictures, which shows a better connection between fillers and matrix. The XRD has been used to illustrate the change in the crystallization. The improvement in both polarization and breakdown field make the composite suitable for energy storage usage.

Fig. 1. P-E loop of polymer composites

Refrences:

1- Ke Yu, Hong Wang, Yongcun Zhou, Yuanyuan Bai, and Yujuan Niu, Enhanced dielectric properties of BaTiO3/poly(vinylidene fluoride) nanocomposites for energy storage applications, J. Appl. Phys. 113, 034105 (2013).

2- Laijun Liu, Yanmin Huang, Yunhua Li, Danping Shi, Shaoying Zheng, Shuangshuang Wu, Liang Fang, Changzheng Hu. Dielectric and non-Ohmic properties of CaCu3Ti4O12 ceramics modified with NiO, SnO2, SiO2, and Al2O3 additives. J Mater Sci (2012) 47:2294–2299

3- Qiaoli Zhang, Tao Li, Zhenping Chen, Renzhong Xue, Yongqiang Wang, The non-ohmic and dielectric behavior evolution of CaCu3Ti4O12 after heat treatments in oxygen-rich atmosphere. Materials Science and Engineering B 177 (2012) 168–172

4- Mojtaba Rahimabady, Shuting Chen, Kui Yao, Francis Eng Hock Tay, and Li Lu, High electric breakdown strength and energy density in vinylidene fluorideoligomer/poly(vinylidene fluoride) blend thin films, Appl. Phys. Lett. 99, 142901 (2011)

5- M. Mohammadi, P. Alizadeh, F.J. Clemens, Effect of SiO2 on sintering and dielectric properties of CaCu3Ti4O12 nanofibers, Journal of Alloys and Compounds 688 (2016) 270e279