Flexible lead-free piezoelectric nano fibers composites of BNT-ST(0.78Bi(0.5)Na(0.5)TiO(3)-0.22SrTiO(3)) ceramic and polyvinylidenefluoride (PVDF) polymer were synthesized by an electrospinning method. The as prepared BNT-ST/PVDF nanofibers composite with different BNT-ST concentrations from 0 wt% to 80 wt% were characterized by XRD, FE-SEM and EDS to investigate the crystal structure, microstructure and morphology. The piezoelectric characteristics were analyzed by the polarization-electric field (P-E) loops, and the results demonstrated that a BNT-ST content of 60 wt% had enhanced piezoelectric characteristics. The possibility of frequency sensor application was confirmed by measuring the output voltage as a function of the frequency of the BNT-ST/PVDF nanofiber composite with a BNT-ST content of 60 wt%. (C) 2016 Elsevier B.V. All rights reserved.