Ceramics-polymer nanocomposites consisting of core-shell structured BaTiO 3 @Al 2 O 3 (BT@Al 2 O 3 ) nanoparticles as the filler and poly(vinylidene fluoride) (PVDF) as the polymer matrix were fabricated by solution casting. At the same volume fraction, the BT@Al 2 O 3 /PVDF nanocomposites, with larger dielectric constant and higher energy density, outperformed the BT/PVDF nanocomposites. The 2.5 vol% BT@Al 2 O 3 /PVDF nanocomposites at 360 MV/m had a double more energy density than pure PVDF at 400 MV/m (6.19 vs. 2.30 J/cm 3 ), and a remarkably 42% lower remnant polarization than the 2.5 vol% BT/PVDF nanocomposites (0.99 vs. 1.69 μC/cm 2 at 300 MV/m). Such significant enhancement was closely related to the surface modification by Al 2 O 3 , which improved the insulation of BT nanoparticles and reduced the contrast of dielectric constant between the filler and the PVDF matrix. [ABSTRACT FROM AUTHOR]