Fish gelatin-based triboelectric nanogenerator for harvesting of biomechanical energy and self-powered sensing of human physiological signals.

Triboelectric nanogenerator (TENG) has been proven effective in converting biomechanical energy into electrical energy, which is expected to be a new energy supply device for wearable electronics and can be utilized as a self-powered sensor. In this work, we have developed a flexible, eco-friendly and multifunctional fish gelatin-based triboelectric nanogenerator (FG-TENG) composed of fish gelatin (FG) film and polytetrafluoroethylene/polydimethylsiloxane (PTFE/PDMS) composite film. The open circuit voltage (Voc), short circuit current (Isc) and output power density of this FG-TENG could reach up to 130 V, 0.35 μA and 45.8 μW cm-2, respectively, which were significantly higher than those TENGs based on other commonly used positive friction materials such as aluminum foil, polyethylene terephthalate (PET) and print paper. The superior performance of the FG-TENG is attributed to the strong electron donating ability of the FG during the triboelectric process. The generated electric energy was high enough to light up 50 commercial light-emitting diodes directly. Importantly, owing to the high stability and excellent sensitivity of the FG-TENG, it has been used as a self-powered sensor for real-time monitoring of the human physiological signals such as finger touch, joint movement and respiration. Furthermore, to expand the usages in real-life applications, a foldable FG-TENG was fabricated by adopting the Miura folding to monitor human movements in real time. This work provides an economical, simple and environmentally friendly approach to fabricate a biomechanical energy harvester, which has a great potential in powering next-generation wearable electronics and monitoring human physiological signals.