Fabrication of graphene oxide/nickelous hydroxide nanosheets hybrid filler to improve the energy density of poly(vinylidene fluoride) based dielectric composites

This study demonstrates a one-step and environmental friendly method to fabricate graphene/nickelous hydroxide (GO/Ni(OH)
₂
) hybrid filler via hydrothermal strategy for dielectric polymer composites based on PVDF. Ni(OH)
₂
nanosheets are grown uniformly on the surface of GO sheets, such hybrid filler can bring a number of advantages for resulted composites: 1. Ni(OH)
₂
could reduce the dielectric constant contrast between graphene and PVDF; 2. The special structure of such hybrid filler could lead to enhanced breakdown strength; 3. Strong interfacial interaction between filler and matrix could be achieved due to the hydroxyl groups on the surface of such hybrid filler. As a result, 1.25 wt% of such hybrid filler leads to dielectric constant of 12.05 at 103 Hz for the final composites, which is higher than neat PVDF (≈9.6). While the tanô is limited at 0.011 which is much lower than GO based composites. And the breakdown strength is 254 kV mm
^-1
, an enhancement of 20.9% over neat PVDF. More importantly, an energy density of 3.89 J cm
^-3
can be achieved, with an enhancement of 2.6 times over GO/PVDF (1.47 J cm
^-3
) and 1.57 times over neat PVDF (2.47 J cm
^-3
). Furthermore, this study provides a one-step environmental friendly method for the fabrication of functional filler for various functional polymer nanocomposites.