Direct-current energy generators from polypyrrole-coated fabric/metal Schottky diodes with considerably improved output

Abstract

Energy generators that can directly convert mechanical forces into direct current (DC) power are highly promising for energy harvesting and the development of self-powered electronic technology. However, most DC generators developed so far produce a very low electrical output. The development of large output DC generators is still a challenge. In this study, a fabric-based DC generator that can produce a peak voltage output as high as 3.27 V and a current output up to 0.82 A m⁻² is developed for the first time. The device is composed of a Schottky diode formed by polypyrrole (PPy)-coated fabric and aluminum metal. Compared with the previously reported Al/PPy/Au Schottky generator that was prepared from a dense PPy plate, our fabric device has 4.6 times higher voltage output and 3.4 times higher power. Its energy conversion was found to come from both Schottky triboelectric and Schottky piezoelectric conversion principles, which is quite different from that of the previously reported Schottky DC generators. However, unlike conventional triboelectric generators that need the internal components to come into contact and separate during the energy conversion process, our device does not need to put the internal components in frequent contact and separation. All the components in this device maintain contact during the whole operation process. The electric energy generated can be used directly to power electronic equipment and be stored in a power bank for future use. Also, the device has good flexibility. It may have a great application prospect in the development of flexible power generation technology.