Poly(vinylidene fluoride) (PVDF) is a piezoelectric material with outstanding physical and mechanical properties. The piezoelectric properties depend on the β-phase content of this polymer, while the physical and mechanical properties depend on the morphology and degree of crystallinity of the material. Silver has antibacterial effects, and silver nanoparticles (Ag-NPs) have large surface areas rich in electrons. In this paper, we produced electrospun PVDF fibrous mats that contained different contents of Ag-NPs between 0% and 1.0%. The β-content in PVDF was found to increase by about 8% for Ag-NPs content of 0.4-0.6%. The electrospun fiber mats had a higher β-crystalline content, nano-pores were visible on the fiber surfaces, and the tensile strength and thermal stability were improved. Dielectric analysis indicated weak interfacial adhesion between the PVDF and AgNPs. Good piezoelectric response was observed in the electrospun fibers containing 0.4% AgNPs, which shows a good correlation between the β-crystalline phase content of the composites and its energy-harvesting application.