Significantly enhanced breakdown strength and energy density in sandwich-structured nanocomposites with low-level BaTiO3 nanowires

By Ru Guo, Hang Luo, Mingyang Yan, Xuefan Zhou, K. Zhou, Dou Zhang. Nano Energy, 2021

224 citations recorded by the source corpus.

Abstract Low energy densities of polymer-based composites restrict their application in miniaturization and integration of dielectric capacitors. Recently, multilayered hierarchical polymer composite is emerging as a promising route to address the aforementioned challenges. In most cases, high loading (>10 wt%) of ceramic nanoparticles were incorporated into polymer matrix to act as a hard layer for high permittivity. In fact, high-loading filler will inevitably cause agglomerations and deteriorate electric breakdown strength due to the poor dispersion and compatibility between the fillers and matrix. One-dimension nanowires exhibit obvious superiority to increase the permittivity of the nanocomposites due to large dipole moments from its high aspect ratios. In this work, a novel strategy of designing sandwich structured PVDF nanocomposites with low-loading BaTiO3 nanowires was proposed. The motivation is to maintain high breakdown strength by the contribution of barrier effect from the sandwich structure and low-loading of BaTiO3 nanowire fillers. Two sandwich structures including ″3-0-3″ and ″0-3-0″ (the digit representing BaTiO3 nanowires mass fraction in each layer) and single-layered BaTiO3/PVDF nanocomposites are fabricated for optimization and comparison. The results revealed that due to the contribution of interfacial polarization and barrier effect between adjacent layers, sandwich-structured BaTiO3/PVDF nanocomposites deliver greatly improved polarization, enhanced electric breakdown strength, and limited leakage current density, which significantly outperform single-layered films. For instance, a high breakdown strength of 519 kV mm−1 with a high maximum polarization of 12.1 μC cm−2, and an impressive discharged energy density of 19.1 J cm−3 accompanied with energy efficiency of 68.6% were achieved even at a very low filler loading of 3 wt% BaTiO3 nanowires. In addition, the potential applications of the nanocomposites for energy storage have been further demonstrated by keeping stable performance after 106 charge-discharge cycles.

Subfields: Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/24b89ee77117b33546907302b3acb1379e2a4b4b