PVDF/Ni NWs Composite Films: A High‐Performance N‐Type Thermoelectric Material for Flexible Energy Harvesting

ABSTRACT This study reports the fabrication and characterization of PVDF/Ni nanowire (NW) composite films for thermoelectric (TE) applications. The composite films were prepared with varying Ni NW concentrations (30–90 wt. %) by dispersing them in PVDF using dimethylformamide (DMF) as a solvent, followed by a drying process to form uniform films. X‐ray diffraction (XRD) and fourier‐transform infrared spectroscopy (FTIR) analyses confirmed the presence of α and β crystalline phases in the PVDF matrix, while scanning electron microscopy (SEM) showed uniform dispersion of Ni NWs, forming conductive pathways. X‐ray photoelectron spectroscopy (XPS) analysis provided insights into the chemical states and interactions within the composites. Electrical characterization revealed that increasing Ni NW content enhanced electrical conductivity, while maintaining consistent n‐type Seebeck behavior. The composite with 90 wt. % Ni exhibited the highest power factor of 15.1 μW/m·K 2 at room temperature and reached an optimized value of 120 μW/m·K 2 at 400 K outperforming similar PVDF‐based materials reported in the literature. Furthermore, a flexible thermoelectric generator (TEG) was developed using p‐type PEDOT and n‐type PVDF/Ni NW composites, achieving a maximum power output ( P max ) of 230 nW at a temperature difference (ΔT) of 25 K. These findings demonstrate the potential of PVDF/Ni NW composites for use in flexible, wearable thermoelectric energy‐harvesting devices.