This study reports on novel poly(vinylidene fluoride)/poly(3,4-ethylenedioxythiophene) (PVDF/PEDT) blend and nanocomposite. Polyaniline functional nanodiamond (PANI-ND) was prepared through in situ route and reinforced in blend to form PVDF/PEDT/PANI-ND. Field-emission scanning electron microscopic analysis revealed consistently dispersed and interlinked bead-like morphology owing to physical interaction in matrix–nanodiamond. Transmission electron microscopy also revealed spherical nanoparticles dispersed in the matrix. Tensile strength and modulus for neat PVDF/PEDT blend were found to be 44.2 MPa and 20.2 GPa, respectively. PVDF/PEDT/PANI-ND 5 with 5 wt% PANI-ND showed high tensile strength and modulus of 61.5 MPa and 152.7 GPa. In this way, strength and modulus of PVDF/PEDT/PANI-ND 5 was 22% and 87% (respectively) higher than the pristine blend. Nanofiller reinforcement (5 wt%) also enhanced the 10% degradation temperature from 421°C (neat blend) to 555°C and maximum decomposition temperature from 466°C to 588°C. Moreover, PANI-ND addition from 0.1–5 wt% enhanced the electrical properties from 10−3–2.1 S cm−1(at room temperature). At 100°C, electrical conductivity of all nanocomposite was increased and maximum value was attained for PVDF/PEDT/PANI-ND 5 (3.0 S cm−1). PVDF/PEDT/PANI-ND 5 electrode exposed rapid Li+-ion diffusion, electron transfer, and electrical conductivity profile. Electrochemical impedance spectroscopy exhibited specific capacity and Coulombic efficiency of 900 mA h g−1and 90% after 300 cycles.