The effect of fabric properties on the performance of a textile based ferroelectret generator toward human body energy harvesting

This paper reports the lamination of two thin fluorinated ethylene propylene (FEP) films onto the back and front surfaces of a conventional textile forming a sandwich structure which creates a textile-based ferroelectret. In this work, we study the effect of the physical properties and dimensions of the textile on the piezoelectric properties and energy harvesting performance of the ferroelectret. Five different fabrics with different thicknesses and Young's modulus were used to form textile based ferroelectret harvesters. Thinner textiles result in increased piezoelectric properties of the fabricated FEP textile ferroelectret. The highest measured stable maximum piezoelectric coefficient d33 of 987 pC N−1 was achieved by the thinnest silk textile FEP ferroelectret. The energy harvester based on the FEP-silk textile ferroelectret generates a peak output power density of 2.26 µW cm−2. The textile ferroelectret can charge a 10 µF capacitor used to store the harvested energy to 3.2 V in 40 s. This corresponds to an average output power of 1.07 µW when subjected to compressive pressures of 30 kPa applied at a frequency of 1 Hz with a 90 MΩ loading resistance.