Triboelectric nanogenerator based on magnetically induced retractable spring steel tapes for efficient energy harvesting of large amplitude motion

The triboelectric nanogenerator has attracted global attention since it was proposed in 2012; the exploration of new applications is ongoing with much enthusiasm in this field. In this paper, we present a novel triboelectric nanogenerator based on magnetically induced retractable spring steel tapes (MR-TENG) to develop energy harvesting from large amplitude periodic motion, which is an ingenious design that employs a new material. The tape-like structural design ensures that the contact/separate direction of the friction layers is perpendicular to the direction of the external force, breaking the amplitude limitation of previous nanogenerators with vertical contact/separate motion. Combined with flexible spring steel tapes, this design enables portability thus widening its application. The working mechanism and factors that may affect the output performance are systematically studied. The results show that the maximum short-circuit current, open-circuit voltage and instantaneous power are 21 mu A, 342 V, and 1.8 mW, respectively. Moreover, we also demonstrate the great potential of the MR-TENG to serve as a self-powered displacement sensor and portable emergency power supply. This work greatly widens the applications of triboelectric nanogenerators (TENGs) through new material selection and innovative structural design.