Frequency influence on freestanding-mode triboelectric nanogenerators

Abstract

Frequency changes have a big effect on the charge transfer efficiency of triboelectric nanogenerators (TENGs), which in turn impacts their overall performance. However, there has been limited research on how frequency affects freestanding-mode TENGs (F-TENGs). In this study, we introduce a Cylindrical Freestanding-Mode Triboelectric Nanogenerator (CF-TENG) that uses a unique cylindrical design and grating electrodes to improve charge transfer efficiency and make better use of space. We also develop a detailed theoretical model to study the electrical behavior of the CF-TENG at different frequencies (2–12 Hz), including the effect of magnetic pre-stress to optimize its output performance. The results show that increasing the magnetic pre-stress boosts the open-circuit voltage from 52.5 V to 68 V, matching theoretical predictions. Impedance matching tests reveal that as the frequency increases from 2 Hz to 12 Hz, the impedance drops from 66 MΩ to 10 MΩ, which leads to a 4.8-fold increase in power output and a 3.05-fold increase in short-circuit current. Furthermore, the CF-TENG charges a 22 μF capacitor much faster at higher frequencies, reaching 2.59 V in 150 s.