  We demonstrate the potential of dopamine modified
0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Zr0.2Ti0.8)O3 filler incorporated poly-vinylidene
fluoride (PVDF) composite prepared by solution cast method as both flexible
energy storage and harvesting devices. The introduction of dopamine in filler
surface functionalization acts as bridging elements between filler and polymer
matrix and results in a better filler dispersion and an improved dielectric
loss tangent (<0.02) along with dielectric permittivity ranges from 9 to 34
which is favorable for both energy harvesting and storage. Additionally, a
significantly low DC conductivity (< 10-9 ohm-1cm-1) for all composites was
achieved leading to an improved breakdown strength and charge accumulation
capability. Maximum breakdown strength of 134 KV/mm and corresponding energy
storage density 0.72 J/cm3 were obtained from the filler content 10 weight%.
The improved energy harvesting performance was characterized by obtaining a
maximum piezoelectric charge constant (d33) = 78 pC/N, and output voltage
(Vout) = 0.84 V along with maximum power density of 3.46 microW/cm3 for the
filler content of 10 wt%. Thus, the results show
0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Zr0.2Ti0.8)O3/PVDF composite has the potential for
energy storage and harvesting applications simultaneously that can
significantly suppress the excess energy loss arises while utilizing different
material.
