Flexible dielectric capacitors are becoming shining stars in modern electronic devices. Ceramic particles with large dielectric constants and benign compatibility are attractive candidates to enhance the energy storage density of pristine polymer capacitors while guaranteeing their flexibility. In this work, double-shell structure of Al2O3 (AO) and dopamine (PDA) were successively coated on the Nd-doped BaTiO3 (NBT) particles and then introduced into the Poly(vinylidene fluoride) (PVDF) matrix. Obvious enhancement in dielectric constants was observed while the dielectric loss remained nearly constant. For the composite films with 1–4[Formula: see text]vol.% NBT@AO@PDA NPs, the maximum energy density of 9.1[Formula: see text]J/cm3 and energy efficiency of 65% was achieved at 430[Formula: see text]MV/m in the sample with 1[Formula: see text]vol.% filling ratio, which are 1.4 and 1.3 times larger than those of pristine PVDF at 450[Formula: see text]MV/m. The finite element simulation reveals the effective relief of the electric field concentration in the composite film induced by the AO and PDA layers. The greater improvement in the energy storage performance could be anticipated if the dispersity of NBT@AO@PDA NPs was further improved.
Effect of solvent on the energy storage property of poly(vinylidene fluoride-hexafluoropropylene)