Enhanced flexible piezoelectric energy harvesters based on BaZrTiO3–BaCaTiO3 nanoparticles/PVDF composite films with Cu floating electrodes

Flexible piezoelectric energy harvesters (FPEHs) were fabricated by employing different types of composite materials based on lead-free piezoelectric nanoparticles (LPNPs) and polyvinylidene fluoride (PVDF) with floating electrodes. The floating electrode effects were analyzed through an experiment and simulation. Different types of LPNPs (BaTiO3, Ba(Zr0.04Ti0.96)O3 (BZT), 1-mol% Cu-doped BZT, Ba(Zr0.2Ti0.8)O3–50(Ba0.7Ca0.3)TiO3 (BZT–BCT), and 1-mol% Cu-doped BZT–BCT)/PVDF composite films were evaluated for FPEH applications. The FPEH based on the BZT–BCT nanoparticles (NPs)/PVDF composite film with floating electrode exhibited a high performance. The highest energy density (2.79 mJ/cm3) was obtained for the FPEH based on the BZT–BCT NPs/PVDF composite film with floating electrode. The results suggest that upon the introduction of the floating electrodes (Cu) into the BZT–BCT NPs/PVDF composite film, charges could be more easily attracted to the floating electrodes that facilitated the collection of charge into the electrodes. [Display omitted] •Flexible piezoelectric energy harvesters with floating electrodes showed high performance.•The highest energy density of 2.79 mJ/cm3 was obtained from Cu-BZT-BCT with PVDF film.•Charges can be more easily attracted to the Cu to help collection of charge into the electrodes.