Enhanced energy storage density and efficiency of nanocomposite dielectrics by modifying polymer matrix and aminated boron nitride nanosheet

Polymers and fillers with high dielectric constant (epsilon r), charge-discharge efficiency (eta) and breakdown strength (Eb) are fundamental to the development of nanocomposite dielectrics for superior energy storage capabilities. Herein, high-epsilon r P(VDF-TrFE) is used to prepare the P(VDF-TrFE)-g-PMMA matrix with elevated epsilon r and eta, then the P(VDF-TrFE)-g-PMMA/BNNS-NH2 nanocomposites with uniformly oriented distribution of h-BN is obtained by a squeegee casting process using amino-boron nitride (BNNS-NH2) as fillers. Thanks to the limiting effect of PMMA and the high insulating effect of BNNS-NH2, the energy storage density (Ue) of the nanocomposite is up to 15.1 J/ cm3 at 500 MV/m, which is 358 % and 182 % of the original P(VDF-TrFE). Furthermore, the eta could reach to 72 %, being 184 % of neat polymer. These results demonstrate that the coordinated enhancement of Ue and eta is critical for high performance energy storage, which provide scientific and technological support for the practicability of PVDF-based dielectrics.