Figure of merit comparison of PP-based electret and PVDF-based piezoelectric polymer energy harvesters
Figure of merit comparison of PP-based electret and PVDF-based piezoelectric polymer energy harvesters
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DOI：
10.1117/12.2222283
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发表时间：
2016-04
期刊：
影响因子：
--
通讯作者：
M. Mrlík;S. Leadenham;M. A. AlMaadeed;A. Erturk
中科院分区：
文献类型：
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作者：
M. Mrlík;S. Leadenham;M. A. AlMaadeed;A. Erturk
在过去的二十年里，机械应变和动能的收集已经受到了极大的关注，以便为无线电子元件供电，如被动和主动监测应用中使用的元件。压电陶瓷，如PZT（锆钛酸铅），是振动能量采集器中最常用的机电接口。然而，由于其低允许曲率和脆性，压电陶瓷在某些应用中不能使用。软聚合物PVDF（聚偏氟乙烯）可以说是这种情况下最流行的非陶瓷软压电能量采集器材料。另一种较少受到关注的聚合物是PP（聚丙烯），用于使用厚度模式（33模式）的驻极体能量收集。本研究展示了PP与PVDF在厚度模式下非谐振能量收集的优点比较图，揭示了PP相对于PVDF的实质性优势。对于在合理的环境振动频率下的厚度模式能量收集场景（例如动态压缩），最大功率输出的优值与有效压电应变常数除以有效介电常数的平方成正比。在最佳条件下，相同体积下，由于PP具有较大的有效压电应变常数和较低的介电常数，其产生的电功率比PVDF高出两个数量级以上。
The harvesting of mechanical strain and kinetic energy has received great attention over the past two decades in order to power wireless electronic components such as those used in passive and active monitoring applications. Piezoelectric ceramics, such as PZT (lead zirconate titanate), constitute the most commonly used electromechanical interface in vibration energy harvesters. However, there are applications in which piezoelectric ceramics cannot be used due to their low allowable curvature and brittle nature. Soft polymer PVDF (polyvinylidene fluoride) is arguably the most popular non-ceramic soft piezoelectric energy harvester material for such scenarios. Another type of polymer that has received less attention is PP (polypropylene) for electret-based energy harvesting using the thickness mode (33- mode). This work presents figure of merit comparison of PP versus PVDF for off-resonant energy harvesting in thickness mode operation, revealing substantial advantage of PP over PVDF. For thickness mode energy harvesting scenarios (e.g. dynamic compression) at reasonable ambient vibration frequencies, the figure of merit for the maximum power output is proportional to the square of the effective piezoelectric strain constant divided by the effective permittivity constant. Under optimal conditions and for the same volume, it is shown that PP can generate more than two orders of magnitude larger electrical power as compared to PVDF due to the larger effective piezoelectric strain constant and lower permittivity of the former.