Fabrication of core-shell structured Ni@BaTiO3 scaffolds for polymer composites with ultrahigh dielectric constant and low loss

Dielectric composites have drawn increasing attention owing to their wide applications in electrical systems. Herein, a novel design of dielectric composites consisting of core-shell structured porous Ni@BaTiO3 scaffolds infiltrated with epoxy was developed. It is demonstrated that the dielectric constants of the composites could be as high as 6397@10 kHz, which is approximately 1777 times higher than pure epoxy matrix (epsilon(r) approximate to 3.6@10 kHz). Meanwhile, the dielectric loss (tan delta approximate to 0.04@10 kHz) remains comparable to that of pure epoxy (tan delta approximate to 0.01@10 kHz). It is believed that the strong charge accumulation and interfacial polarizations on the huge interfaces, especially the Ni/BaTiO3 and Ni/epoxy interfaces, give arise to the substantially enhanced epsilon(r). Besides, the sintered insulating BaTiO3 coating can block the transportation of charge carriers, resulting in the low loss. The ultrahigh dielectric constants and low loss make these composites promising candidates for microstrip antennas, field-effect transistors and dielectric capacitors.