To enhance the energy storage performance of PVDF-based polymer dielectric films, layered structured polymer nanocomposites were prepared by solution casting method. The middle layer utilized poly(methyl methacrylate) (PMMA) with a volume fraction of 30% to suppress energy loss, while the outer layers employed poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) to provide high dielectric constant. Inorganic BaTiO3 (BT) nano-ceramic particles were uniformly dispersed as fillers in the outer layers. By adjusting the filler content, its effects on the dielectric constant, electric strength, and energy density of the composites were investigated, along with the durability and stability of the films’ energy storage performance under different cycle numbers and in different regions. The results show that the addition of a low content of BT increases the dielectric constant, suppresses the dielectric loss, and reduces the leakage current density of the films. The composite with 5% mass fraction of nano-fillers achieves a discharge energy density as high as 15.5 J/cm3 at an electric field of 425 kV/mm, which is higher than the energy storage densities of most reported PVDF and its copolymer-based composites. The variations in discharge energy density after 10 000 cycles and across eight different regions do not exceed 19% and 7%, respectively.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |