Poly(methyl methacrylate)/boron nitride nanocomposites with enhanced energy density as high temperature dielectrics

The development of advanced dielectric materials with high electric energy densities at elevated temperatures is of crucial importance in modern electronics and electric power systems. Herein, poly(methyl methacrylate) (PMMA)/boron nitride nanosheets (BNNS) nanocomposites for high temperature applications were prepared using a facile solution cast method. It was found the incorporation of BNNS into PMMA increased the thermal conductivity and enhanced the capacitive properties of the nanocomposites. A discharged energy density that is over 210% that of the state-of-the-art biaxially oriented polypropylene (BOPP) and a charge-discharge efficiency of more than 97% have been achieved in PMMA/BNNS under an electric field of 200 MV/m at 70 °C. The incorporation of uniformly dispersed nanosheets into polymer matrix as charge-blocking barrier paves a way to significant reduction of conduction loss in high temperature dielectrics.