Synergistically improving dielectric permittivity and breakdown strength of ceramic dielectric via introducing monodispersed gold nanoparticles

Ceramic dielectrics have been extensively studied due to their high-power density and fast charge/discharge rate. However, simultaneously increasing their dielectric permittivity and breakdown strength remains a formidable challenge. Here, the novel sandwich structure ceramic dielectrics are designed, in which monodisperse gold nanoparticles are sandwiched by two ceramic layers. The effects of gold nanoparticles with different sputtering times on the dielectric breakdown performance of the composite ceramics are investigated. The results show that the dielectric permittivity and breakdown strength of barium titanate composite ceramics with 3 min gold nanoparticle interlayer (BT-3Au-BT) reach 6017.5 (10 kHz) and 111.4 kV/cm, respectively, which are 9 % and 18 % higher than that of barium titanate ceramics without gold nanoparticle interlayer (BT-0Au-BT). The improved dielectric permittivity is originated from the formation of numerous micro-capacitors. The enhanced breakdown strength is attributed to the Coulomb blockade effect of gold nanoparticles. This work provides a novel, easy-to-operate and scalable approach for synergistically improving the dielectric permittivity and breakdown strength of dielectric materials, which opens up a novel way for the design of high-performance dielectric materials and would also be enlightening for the exploration of other functional nanocomposites.