Obtaining Greatly Improved Dielectric Constant in BaTiO3-Epoxy Composites with Low Ceramic Volume Fraction by Enhancing the Connectivity of Ceramic Phase

Ceramic-polymer dielectric composites show promising potential as embedded capacitors, whereas it is a great challenge to obtain a high dielectric constant (epsilon(r)) at a low ceramic volume fraction (V-c). This work demonstrates a strategy for overcoming this challange. By employing a high sintering temperature (T-s) and introducing porogen, BaTiO3 ceramics with both great connectivity and high porosity are obtained, and the composites with improved epsilon(r) at a low V-c are prepared after curing the epoxy monomer, which is infiltrated into the porous ceramic bodies. For the composite with a T-s of 1300 degrees C and a V-c of 38.1%, the epsilon(r) is as high as 466.8 at 1 kHz, which is improved by about nine times compared to the 0-3 counterpart with a higher V-c of 60.8%. Furthermore, the composite exhibits low dielectric loss and good frequency and temperature stability of epsilon(r), indicating the great potential for practical applications. Finite element simulation shows that the enhanced connectivity of BaTiO3 increases the electric field intensity in high-epsilon(r) BaTiO3 dramatically and therefore plays a key role in the dielectric response of the composite. This work not only sheds light on the high-epsilon(r) ceramic-polymer composites but also deepens the understanding on the relationship between their properties and microstructures.

Automated summary

This study demonstrates a strategy to overcome the challenge of obtaining a high dielectric constant in ceramic-polymer composites with low ceramic volume fraction. By using a high sintering temperature and introducing a porogen, the researchers were able to obtain BaTiO3 ceramics with high porosity and great connectivity. The composites prepared with these ceramics showed improved dielectric constants at low ceramic volume fractions. The composite with a sintering temperature of 1300 degrees C and a ceramic volume fraction of 38.1% exhibited a dielectric constant of 466.8, which was about nine times higher compared to the counterpart with a higher ceramic volume fraction of 60.8%. The composite also exhibited low dielectric loss and good frequency and temperature stability, indicating its potential for practical applications. Finite element simulation showed that the enhanced connectivity of BaTiO3 played a key role in the dielectric response of the composite.