Decoupling Contact and Rotary Triboelectrification vs Materials Property: Toward Understanding the Origin of Direct-Current Generation in TENG

Direct-current (DC) triboelectric nanogenerators (TENGs) are increasingly recognized as next-generation power sources for widespread applications. Research has recently focused on developing novel materials as active layers for DC TENGs and device configurations to elucidate the working mechanisms. In this work, we report the use of a carbyne (dehydrohalogenated poly(vinylidene fluoride) (PVDF)) film as a positive-type friction layer for DC TENGs for efficient harvesting of rotary energy. The fabricated carbyne-based rotary TENG generates an output voltage (120 V) with excellent mechanical stability and peak power density (500 μW m^-2). The mechanism of DC output generation from the carbyne-based rotary TENG is explained based on halogen removal from PVDF and the electrostatic breakdown effect. Additionally, the humidity effects on the fabricated carbyne-based rotary TENG toward a self-powered humidity sensor are studied in detail with the aid of in situ Raman analysis, Fourier transform infrared spectroscopy, and open-circuit potential measurements. Together, our experimental results demonstrate that using carbyne as an active triboelectric layer for DC TENGs would greatly benefit the next generation of power devices.