MOF-derived ZrO2/C-polyvinylidene fluoride composite towards negative permittivity regulation mechanism

Composites featuring negative permittivity have garnered significant attention for their potential in novel capacitance designs, coil-less electrical inductors, and electromagnetic shielding applications. In this study, we prepared polyvinylidene fluoride (PVDF) matrix composites filled with ZrO2/C nanoparticles derived from metal-organic frameworks (MOFs) via a hot-pressing method. With an increase in the ZrO2/C content to 30 wt.%, electrical percolation was observed, accompanied by a transition mechanism from hopping conduction to metal-like conduction. This enabled the realization of ZrO2/C/PVDF composites with tailorable negative permittivity properties, attributed to the plasmonic oscillation of free electrons in the composites beyond the percolation threshold (30 wt.%). Furthermore, the permittivity transition along to a shift in the electrical behavior of the percolative composites from capacitive to inductive. We explored the regulatory mechanism behind the negative permittivity in this random composite system, and our findings highlight the potential of these tunable negative permittivity media as promising candidates for diverse electromagnetic applications.