Asymmetric filler engineering of PVDF nanocomposites for high-energy-storage density via synergistic MXene/Al2O3 hybrids

Traditional polymer-based dielectric energy storage materials are typically limited by the compromise between low dielectric permittivity and inadequate breakdown strength. This trade-off represents a major bottleneck that severely restricts the enhancement of energy storage performance. In this work, we introduced a ternary composite design that synergistically integrates two-dimensional MXene nanosheets and insulating Al 2 O 3 nanoparticles into a polyvinylidene fluoride (PVDF) matrix. In this structure, the MXene component induces strong interfacial polarization, significantly enhancing the effective dielectric constant, while the Al 2 O 3 filler acts as a nanoscale barrier, inhibiting charge injection and leakage conduction, thereby maintaining high breakdown strength. With a low filler loading of 0.2 wt%, the film demonstrated a dielectric permittivity of 18.15 and a dielectric loss of 0.028. Moreover, the breakdown strength attained 124% of that measured for pure PVDF, and the maximum discharge energy density increased to 4.76 J/cm 3 . This design provides a novel route for energy storage utilizing advanced dielectric materials. Download: Download high-res image (238KB) Download: Download full-size image