Enhanced Energy Storage Capacity in NBT Micro-Flake Incorporated PVDF Composites

In recent years, dielectric films with a high energy-storage capacity have attracted significant attention due to their wide applications in the fields of renewable energy, electronic devices, and power systems. Their fundamental principle relies on the polarization and depolarization processes of dielectric materials under external electric fields to store and release electrical energy, featuring a high power density and high charge-discharge efficiency. In this study, sodium bismuth titanate (NBT) micro-flakes synthesized via a molten salt method were treated with hydrogen peroxide and subsequently blended with a polyvinylidene fluoride (PVDF) matrix. An oriented tape-casting process was utilized to fabricate a dielectric thin film with enhanced energy storage capacity under a weakened electric field. Experimental results demonstrated that the introduction of modified NBT micro-flakes facilitated the interfacial interactions between the ceramic fillers and polymer matrix. Additionally, chemical interactions between surface hydroxyl groups and fluorine atoms within PVDF promoted the phase transition from the α to the β phase. Consequently, the energy storage density of PVDF-NBT composite increased from 2.8 J cm^-3 to 6.1 J cm^-3, representing a 110% enhancement. This design strategy provides novel insights for material innovation and interfacial engineering, showcasing promising potential for next-generation power systems.