Structure‐Piezoelectric Coupling in P( VDF ‐ TrFE )/ ZnO / CMWCNT Composite Films for Piezoelectric and Triboelectric Nanogenerators

ABSTRACT Ferroelectric polymers are promising candidates for flexible energy harvesting owing to their piezoelectricity, low density, flexibility, and environmental compatibility. Herein, P(VDF‐TrFE) composite films containing ZnO nanoparticles and carboxylated multi walled carbon nanotubes (CMWCNTs) were prepared, and their structure and electrical properties were regulated by hot rolling. ZnO nanoparticles acted as heterogeneous nucleating agents to promote β‐phase formation, while CMWCNTs enhanced dielectric response through the microcapacitor effect. The optimized composite contained 1.08 wt% ZnO and 0.02 wt% CMWCNTs. With increasing rolling temperature, molecular orientation was progressively improved, and the film rolled at 90°C exhibited an orientation degree of 0.66, high β‐phase fraction, remanent polarization of 22 μC cm −2 , piezoelectric coefficient of 46 pC N −1 , and relative dielectric constant of 19.4. A piezoelectric triboelectric nanogenerator based on this film delivered a maximum output voltage of 31 V and a power density of 15.3 μW cm −2 . This work clarifies how ZnO nucleation, CMWCNT assisted dielectric regulation, and hot rolling induced orientation jointly modulate the structure and output performance of P(VDF‐TrFE) based ternary composite films.