Triboelectrification-Induced Electricity in Self-Healing Hydrogel for Mechanical Energy Harvesting and Ultra-sensitive Pressure Monitoring

[Image: see text] Triboelectric nanogenerators (TENGs) have shown huge application potential in the fields of micro–nano energy harvesting and multifunctional sensing. However, the damage of triboelectric material is one of the challenges for their practical applications. Herein, we fabricated a flexible TENG employing self-healing hydrogel and fluorinated ethylene propylene film as triboelectric materials for mechanical energy harvesting and pressure monitoring. The prepared hydrogel not only has excellent flexibility, transparency, and self-healing property but also exhibits good mechanical property without plastic deformation and damage under a large stretchable strain of 200%. The output electric signals of TENGs are as high as 33.0 V and 3 μA under a contact frequency of 0.40 Hz and a pressure of 2.9 N, respectively, which can charge a capacitor of 0.22 μF to 24.3 V within 300 s. Note that the voltage retention rate of TENGs after self-healing is up to 88.0%. Moreover, hydrogel-based TENGs can act as a wearable pressure sensor for monitoring human motion, exhibiting a high sensitivity of 105.9 mV/N or 1.73 nA/N under a contact frequency of 0.40 Hz. This research provides a reference roadmap for designing TENGs and self-powered pressure sensors with flexibility, self-healing, and robustness.