Swelling-enabled charge compensation in conductive hydrogel for triboelectric tactile sensing via active rehydration

Triboelectric nanogenerators (TENGs) typically use insulating polymers as the tribo-layer and different conductive materials as the electrodes. Conductive hydrogels (CHGs) can be used as both the electrode and tribo-layer and simplify the structure of a TENG. However, hydrogel dehydration may cause charge dissipation, impairing long-term performance. Here, we explore the relationship between electrical conductivity and the surface charge density of the TENG. We leverage the active rehydration behavior of hydrogels instead of conventional evaporation suppression to boost the triboelectric output. This is an alternative to existing material modification techniques. The created CHG-TENG achieves a surface charge density of 325 μC·m −2 and a sensitivity of 1,572 mV·kPa −1 . The high-output and electron-donating CHG with high responsivity has potential for applications in tactile sensor arrays.