Improved output performance of triboelectric nanogenerators based on polydimethylsiloxane composites by the capacitive effect of embedded carbon nanotubes

Conductive carbon fillers were commonly used to mix with polydimethylsiloxane to improve the output performance of polydimethylsiloxane-based triboelectric nanogenerators. In this work, we focused on the mechanism underlying the unpredictable output performance influenced by adding conductive fillers. We selected multiwall carbon nanotubes as conductive fillers and investigated their electronegative performance in triboelectric nanogenerators. An optimized performance was achieved when the weight concentration of carbon nanotubes was about 0.4%. The open-circuit voltage can reach up to 720 V, the short-circuit current was about 18.28 μA, and a power density of 4.65 mW (11.62 W/m2) was obtained at the load resistance of 55.15 MΩ and a stimulus frequency of 2.0 Hz. The attractive performance was attributed to the appropriate balance of the capacitive effect and the leakage effect of carbon nanotubes to triboelectric charges. A model based on alternative current impedance analysis has been proposed, which may be helpful for future triboelectric nanogenerator design and investigation.