Record Efficiency of β-Phase PVDF-MXene Composites in Thin Film Dielectric Capacitors

MXene is a new class of graphene like two-dimensional transition metal carbon show promising applications for high electrical conductivity and energy density. PVDF-MXene composites are challenging to fabricate with high quality due to poor interfacial interactions, dispersibility, or flake size. PVDF is a semicrystalline polymer that has excellent potential for thin film dielectric capacitors due to its inherently high dielectric constant and low loss tangent. PVDF’s dielectric constant can be increased by the formation and alignment of its β-phase crystalline structure, which can be facilitated by solvent selection and 2D nanofiller inclusion. MXenes are promising candidates for PVDF thin film capacitors due to their superior dielectric permittivity and ability to greatly increase interfacial polarization. In this work we will present ultra-high energy density and record efficiency of free standing PVDF-MXene thin film capacitors. We observed energy density as high as 45 J/cm³, with 95% efficiency achieved in thin film capacitors. Furthermore, composites are processed using a green and sustainable solvent, propylene carbonate makes this suitable for large scale applications.