Soft X-ray-charged multilayered piezoelectret with embedded electrode for push-button energy harvesting

In this report, we propose a push-button-type kinetic energy harvester using a soft-X-ray-charged multilayered piezoelectret. With the aid of embedded electrodes, the bias voltage is directly applied to each unit cell. With our 9-layer early prototype, output power of 9.9 μJ has been obtained for 0.75 mm displacement within 0.3 s. d₃₃ as high as 14000 pC/N is realized, which is 10 times higher than that for previous piezoelectrets. Power generation by pushing with a finger has also been demonstrated.