Significantly Improved Breakdown Strength of Sandwiched Polymer Dielectrics by Functionalized Boron Nitride Nanosheets

Polymer dielectrics have a wide applications in the field of electric engineering because of its good processibility and low cost. Polyvinylidene fluoride (PVDF) possesses the superior dielectric constant among known polymers and hence attracts tremendous attention in the field of electrostatic capacitors. However, the inferior breakdown strength of PVDF severely restricts its application. Herein, functionalized Boron Nitride Nanosheets (BNNSs) are assembled into the middle of two PVDF layers to enhance the breakdown strength of PVDF, leading to suppressed dielectric loss, enhanced electrical resistivity and hence remarkably improved breakdown strength of sandwiched polymer dielectrics. For example, sandwiched polymer dielectrics exhibit an ultra-high breakdown strength of 673 MV/m, which is 150% of PVDF (449 MV/m). This strategy paves a new way to fabricating high breakdown strength polymer dielectrics.