Utilization of ionic conduction for developing ceramic electrets applicable to vibration power generator

驻极体发电机可以将低频振动(1-100赫兹)直接转化为电能，但由于其生电能力较低，限制了其应用。虽然驻极体上较高的表面电位可以有效地提高功率密度，但目前使用的聚合物驻极体的电势水平几乎饱和，这是因为它们对硬充电处理的抵抗力较差。因此，我们致力于开发基于控制陶瓷中离子迁移和凝聚的新型陶瓷驻极体。通过这项研究，我们发现羟基磷灰石(OHA)在高温下可以在直流电场下被极化。极化后的OHA陶瓷的表面电位达到1000V以上，至少稳定了一年以上。考虑到聚合物驻极体的表面电势被限制在几百伏的事实，OHA驻极体应该是一种很有前途的驻极体发电材料。

An electret power generator can convert low-frequency vibrations (1-100 Hz) directly into electricity, however, the applications are limited because of it's low electrogenic ability. Although the higher surface potential on the electrets is effective to promote the power density, the potential level of currently-used polymer electrets is almost saturated due to their poor resistivity against the hard charging treatment.Hence we aimed to develop new ceramic electrets based on the approach of controlling ionic migrations and their congelation within the ceramics. Through this study, we found that oxyhydroxyaptite (OHA) could be polarized under a dc electrical field at elevated temperature. The surface potential on polarized OHA ceramics reached above 1000 V, which was stable at least over a year. Considering the fact that the surface potential of polymer electrets is limited to several hundred volts, OHA electrets should be promising material applicable to the electret power generator.