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Polymer-based dielectric nanocomposites have attracted great attention due to the advantages of high-power density and stability. However, due to the limited breakdown strength (E b) of the dielectrics, the unsatisfactory energy density becomes the bottleneck that restricts their applications. Here, newly designed sandwich-structured nanocomposites are proposed, which includes the introduction of low-loading 0.4BiFeO3–0.6SrTiO3 (BFSTO) nanofibers into the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix as the polarization layer (B-layer) to offer high permittivity and the selection of poly(methylmethacrylate) (PMMA)/P(VDF-HFP) all-organic blend film as the insulation layer (P-layer) to improve E b of the nanocomposites. The optimized sandwich-structured PBP nanocomposite exhibits significant enhancement in E b (668.6 MV/m), generating a discharged energy density of 17.2 J/cm3. The dielectric and Kelvin probe force microscope results corroborate that the outer P-layer has a low surface charge density, which can markedly impede the charge injection from the electrode/dielectric interface and thereby suppress the leakage current inside the nanocomposite. Furthermore, both the finite element simulations and capacitive series models demonstrate that the homogenized distribution of electric field in the PBP sandwich-structured nanocomposite favors the improvement of energy storage performance. This work not only provides insightful guidance into the in-depth understanding of the dielectric breakdown mechanism in sandwich-structured nanocomposites but also offers a novel paradigm for the development of polymer-based nanocomposites with high E b and discharged energy density.

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Amorphous Ga2O3 (a-Ga2O3) films have attracted considerable attention in the field of photodetectors due to their excellent optical absorption response and photoelectric properties. However, there are few studies utilizing the...

Kombucha is a popular sparkling sugared tea, fermented by a symbiotic culture of acetic acid bacteria (AAB) and yeast. The demand for Kombucha is increasing worldwide mainly due to its perceived health benefits and appealing sensory properties. This study isolated and characterised the dominant AAB and yeast from starter culture and Kombucha broth after 0, 1, 3, 5, 7, 9, 11, and 14 days of fermentation at ambient temperature (~22°C). Changes in the microbial composition were associated with variations in the physico-chemical characteristics of Kombucha tea, such as pH, titratable acidity, and total soluble solids (TSS). During fermentation, the acidity increased, and TSS decreased. The yield, moisture content and water activity of the cellulosic pellicles which had developed by the end of fermentation were attributed to the presence of AAB. Yeast and AAB were isolated from the Kombucha samples using glucose yeast extract mannitol ethanol acetic acid (GYMEA) and yeast extract glucose chloramphenicol (YGC) media respectively, using serial dilutions. Phenotypic and taxonomic identification of AAB and yeast were determined by morphological and biochemical characterisation, followed by sequence analysis of the ribosomal RNA gene (16S rRNA for AAB and ITS for yeast). The dominant AAB species in the cellulosic pellicle and Kombucha broth was identified as Komagataeibacter rhaeticus. The yeast isolates belonged to Debaryomyces prosopidis and Zygosaccharomyces lentus.