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 Hz）直接转化为电能，但由于其产电能力低，应用受到限制。虽然较高的驻极体表面电位能有效提高驻极体的功率密度，但目前使用的聚合物驻极体表面电位已接近饱和，这是由于它们对硬充电处理的抵抗力差，因此我们的目标是通过控制陶瓷中离子的迁移和扩散来开发新的陶瓷驻极体。通过这项研究，我们发现氧羟基磷灰石（OHA）可以在高温下的直流电场极化。极化后的OHA陶瓷表面电位可达1000 V以上，且至少在一年以上保持稳定。考虑到聚合物驻极体的表面电位仅限于几百伏，OHA驻极体应该是适用于驻极体发电机的有前途的材料。

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.