Notably decreased dielectric loss of high dielectric constant P(VDF-TrFE)/CuBTC MOF composites through adding silica powder

High dielectric constant (high- k ) for energy storage is obtained in composites bearing polar polymer matrix and polar metal–organic-framework (MOF) filler via electrostatic interaction between polymer and MOF. Nevertheless, high dielectric loss is caused by dipole coupling in interface region. For both high dielectric constant and low dielectric loss, in this research, insulating silica particles were added into poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))/copper benzene-1,3,5-tricarboxylate (CuBTC) MOF composites to obtain ternary blends. Compared with polymer/CuBTC blends, polymer/CuBTC/silica blends displayed the moderately reduced dielectric constant and significantly decreased dielectric loss/conductivity. In ternary blends, high dielectric constant was from dipoles in CuBTC and polymer/CuBTC interface zone, and low dielectric loss was from silica-induced weak coupling between Cu/F dipoles in polymer/CuBTC interface zone. Ternary blend with 9 wt% CuBTC and 4 wt% silica showed a high dielectric constant of ~ 60 and low dielectric loss of ~ 0.23 at 100 Hz. Novelty of this research was optimizing both polarization and relaxation of Cu/F dipoles via synergy of CuBTC and silica. This study might pave a road for large-scale preparation of high-performance blends applicable in dielectric capacitors. Graphical abstract