Preparation of Cross-linked P(VDF-CTFE-DB)/PMN-PT-Sm Nanocomposite Films and Their Dielectric and Energy Storage Performances [可交联型P(VDF-CTFE-DB)/PMN-PT-Sm纳米复合薄膜的制备及介电和储能性能]

摘要

A fluoropolymer with double bonds (P(VDF-CTFE-DB)) was synthesized via controlled dehydrochlorination of poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)). High permittivity component of samarium-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT-Sm) ferroelectric was selected as the inorganic composite phase, and the cross-linkable P(VDF-CTFE-DB) was used as polymer matrix. Cross-linking P(VDF-CTFE-DB)/PMN-PT-Sm composite film was synthesized by reacting the free radical initiator. The dielectric properties, breakdown strength, energy-storage performances, and solvent resistance of the P(VDF-CTFE-DB)/PMN-PT-Sm nanocomposite films were investigated. As a result, the dielectric constant increases with increasing the volume fraction of PMN-PT-Sm nanoparticles. A maximal dielectric constant of 65 at 100 Hz associated with a dielectric loss of only about 0.058 was obtained in the P(VDF-CTFE-DB)/PMN-PT-Sm nanocomposite film with 30% of PMN-PT-Sm nanoparticle addition. It is experimentally found that the cross-linked network structure has a great influence on the breakdown strength, energy storage performances and compatibility of P(VDF-CTFE-DB)/PMN-PT-Sm nanocomposite films. The significantly improved breakdown strength up to 3 200 kV/cm and the highest discharge energy density of about 9.7 J/cm3 for the cross-linking P(VDF-CTFE-DB)/PMN-PT-Sm nanocomposite film with 20% of PMN-PT-Sm have been achieved. Constructing cross-linked networks among P(VDF-CTFE-DB) and PMN-PT-Sm nanoparticles could be an effective way to decrease the leakage current and dielectric loss, as well as to enhance the breakdown strength and the energy storage performances in the polymer nanocomposites.

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