A typical core-shell structural silver@aluminum oxide (Ag@Al2O3) nanorods was successfully synthesized by silver nitrate reduction method combined with hydrolysis of aluminum sulfate. The Ag@Al2O3 coreshell nanorods were used as functional fillers to improve the dielectric properties of polyvinylidene fluoride (PVDF). The thermal, mechanical and dielectrical properties of PVDF based composites were characterized. A comparative study on the dielectric properties of PVDF based composites with the filler of Ag and Ag@Al2O3 core-shell nanorods was also reported. Results showed that Al2O3 could make a homogeneous shell out of the Ag nanorods, and the Ag@Al2O3 core-shell nanorods also have a good dispersion in PVDF matrix. The Ag@Al2O3/PVDF composites with 15 wt% have a more superior expression on energy density (0.026023 J/cm(3)) within a rather low dielectric loss (0.015) and leakage current density (4.41 E-8 A/cm(2)), and the storage is 1.82 times higher than that of the pure PVDF. This improvement in energy storage of composites should be attributed to the occurrence of Al2O3 shell which effectively prevented the leakage current and resulted the reducement in the dielectric loss of the composites. (C) 2018 Elsevier Ltd. All rights reserved.