State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China.
College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Adv Mater. 2023 Jun;35(22):e2300246. doi: 10.1002/adma.202300246. Epub 2023 Apr 6.
Dielectric elastomer generators (DEGs) with high generated energy density and high conversion efficiency are of great interest. Among several dielectric elastomers (DEs), silicone elastomer filled with ceramic fillers have been extensively studied for their high elasticity, insulation, and permittivity. However, the stretched breakdown strength (E ) of such composites decreases significantly under large strain, thus sharply reduces its energy harvesting performances. In this study, a polar rubber-based dielectric (GNBR) is synthetized and creatively used as "soft filler" for silicone elastomer. Benefiting from the deformability under stretching and its inherent strong interface bonding with silicone elastomer, this soft filler effectively avoids the formation of weak interface under large strain and reduces the local field strength of interface area. As expected, the composite filled with soft filler (GNBR/PMVS) shows enhanced E of 2.8 times that of composite with traditional hard filler (TiO /PMVS) under equibiaxial strain of 200%. As a result, GNBR/PMVS composite exhibits maximum energy density of 130.5 mJ g with up-to-date highest power conversion efficiency of reported DEG (44.5%). The findings will provide new insights in the rational design of DE composites characterized by high stretched breakdown strength for advanced energy harvesting system.
具有高能量密度和高转换效率的介电弹性体发电机（DEG）引起了极大的关注。在几种介电弹性体（DE）中，填充陶瓷填料的硅酮弹性体因其高弹性、绝缘性和介电常数而得到了广泛研究。然而，这种复合材料在大应变下的拉伸击穿强度（E）显著下降，从而大大降低了其能量收集性能。在这项研究中，合成了一种极性橡胶基介电体（GNBR），并创造性地用作硅酮弹性体的“软填料”。得益于拉伸下的可变形性及其与硅酮弹性体固有的强界面结合，这种软填料在大应变下有效地避免了弱界面的形成，降低了界面区域的局部场强。不出所料，在等双轴应变 200%下，填充软填料（GNBR/PMVS）的复合材料的 E 比填充传统硬填料（TiO/PMVS）的复合材料提高了 2.8 倍。结果，GNBR/PMVS 复合材料表现出 130.5 mJ/g 的最大能量密度，是报道的 DEG（44.5%）中最高的功率转换效率。这些发现将为具有高拉伸击穿强度的先进能量收集系统的 DE 复合材料的合理设计提供新的思路。
