PVDF–BaSrTiO3 nanocomposites for flexible electrical energy storage devices

We have explored the energy storage capability of Ba0.5Sr0.5TiO3 (BST)-polyvinylidene fluoride (PVDF) nanocomposites. Morphologically uniform BST colloidal nanocubes were prepared in high yield by a solvothermal method at temperatures as low as 150 degrees C. As-synthesised BST nanocubes were used as fillers (35 vol%) in PVDF polymer matrix. The unique dielectric-polymer films show enhanced dielectric constant (>27) and enhanced electrical breakdown strength (E-b) (2.85 MV/cm). The resulting dielectric energy density for BST-PVDF is 9.7 J/cm(3), which is a result of the interplay between dependencies of permittivity and breakdown strength on volume fraction. We propose that the strong nanoparticle-polymer matrix interfacial interaction is the main reason for the observed improved dielectric properties. This wetchemical-assisted fabrication approach can be readily extended to other combinations of polymers and ceramics with concomitant improvement in properties. Key parameters of various materials (e.g. chemical composition, shape, size and surface reactivity) can be readily controlled in this method, opening up a new pathway to highly flexible macroelectronics.