School of Mechanical, Aerospace, Chemical and Materials Engineering, Arizona State University, Tempe, AZ 85287-6106, USA.
Nanotechnology. 2011 Jan 7;22(1):015702. doi: 10.1088/0957-4484/22/1/015702. Epub 2010 Dec 6.
High energy storage plays an important role in the modern electric industry. Herein, we investigated the role of filler aspect ratio in nanocomposites for energy storage. Nanocomposites were synthesized using lead zirconate titanate (PZT) with two different aspect ratio (nanowires, nanorods) fillers at various volume fractions dispersed in a polyvinylidene fluoride (PVDF) matrix. The permittivity constants of composites containing nanowires (NWs) were higher than those with nanorods (NRs) at the same inclusion volume fraction. It was also indicated that the high frequency loss tangent of samples with PZT nanowires was smaller than for those with nanorods, demonstrating the high electrical energy storage efficiency of the PZT NW nanocomposite. The high aspect ratio PZT NWs showed a 77.8% increase in energy density over the lower aspect ratio PZT NRs, under an electric field of 15 kV mm(-1) and 50% volume fraction. The breakdown strength was found to decrease with the increasing volume fraction of PZT NWs, but to only change slightly from a volume fraction of around 20%-50%. The maximum calculated energy density of nanocomposites is as high as 1.158 J cm(-3) at 50% PZT NWs in PVDF. Since the breakdown strength is lower compared to a PVDF copolymer such as poly(vinylidene fluoride-tertrifluoroethylene-terchlorotrifluoroethylene) P(VDF-TreEE-CTFE) and poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP), the energy density of the nanocomposite could be significantly increased through the use of PZT NWs and a polymer with greater breakdown strength. These results indicate that higher aspect ratio fillers show promising potential to improve the energy density of nanocomposites, leading to the development of advanced capacitors with high energy density.
高储能在现代电力工业中起着重要作用。在此，我们研究了填料纵横比在储能纳米复合材料中的作用。纳米复合材料是通过在聚偏二氟乙烯（PVDF）基质中分散具有不同体积分数的两种不同纵横比（纳米线、纳米棒）填料的锆钛酸铅（PZT）合成的。在相同的包含体积分数下，含有纳米线（NWs）的复合材料的介电常数常数高于含有纳米棒（NRs）的复合材料。还表明，具有 PZT 纳米线的样品的高频损耗角正切值小于具有纳米棒的样品，这表明 PZT NW 纳米复合材料具有高的电能存储效率。高纵横比的 PZT NW 比低纵横比的 PZT NR 在 15 kV mm(-1)和 50%体积分数的电场下，能量密度提高了 77.8%。发现击穿强度随 PZT NW 体积分数的增加而降低，但在 20%-50%体积分数左右仅略有变化。在 50%PZT NWs 的 PVDF 中，纳米复合材料的最大计算能量密度高达 1.158 J cm(-3)。由于与 PVDF 共聚物（如聚（偏二氟乙烯-三氟乙烯-三氯三氟乙烷）P(VDF-TreEE-CTFE)和聚（偏二氟乙烯-六氟丙烯）P(VDF-HFP)相比，击穿强度较低，因此通过使用 PZT NWs 和具有更大击穿强度的聚合物，纳米复合材料的能量密度可以显著提高。这些结果表明，更高纵横比的填料具有提高纳米复合材料能量密度的巨大潜力，从而开发出具有高能量密度的先进电容器。
