Sustainable direct current powering a triboelectric nanogenerator: Via a novel asymmetrical design

Triboelectric nanogenerators (TENGs) typically have very low outputs in terms of root-mean-square (RMS) values as the outputs are in the form of short duration pulses. In order to overcome this limitation, here we introduce multi-phase rotation-type TENGs (MP-TENGs). The rotator of the MP-TENGs consists of alternating components of PTFE and mono cast nylon, whereas the stator consists of PTFE with multiple back electrodes. Each electrode produces an output of the same frequency and amplitude, but of different regularly shifted phases. Consequently, the outputs from all the electrodes are full-wave rectified and superimposed, and the total output of the MP-TENGs is almost constant direct current (DC), unlike typical TENGs, with much higher RMS values. A 5-phase TENG has produced 380 V, 3.6 mA m^-2, and 4.9 W m^-2, and the current crest factor is dramatically decreased to 1.26. Finally, due to the almost constant DC output, the MP-TENGs successfully operate electronic devices and charge a battery.