Solution-Tube-Based Volume Effect Triboelectric Nanogenerator with Salt and pH Sensitivity

Due to the advantages of natural softness and flexibility of water, liquid–solid-based triboelectric nanogenerators (TENGs) have aroused wide attention recently and much effort has been devoted to improving its output performance. Herein, the performance of liquid–solid-based TENG is greatly improved through two simple steps. First, an end electrode is added into the traditional tube-based TENG and the volume effect is successfully realized, with the output voltage improved by ≈40 times to 240 V. Then, the output voltage of the tube-based TENG can be further improved to 461 V by replacing water with NaOH solution and an impressive peak power density of 1910 Wm⁻³ and an average power density of 459 Wm⁻³ can be achieved. Additionally, the demonstration shows that the solution-tube-based volume effect TENG can work well at various operation modes and generate power from multiple mechanical energy sources. In addition to wearable human motion energy recovery, wave energy recovery, and electrochemical cathodic protection systems, the device also shows its application potential in biochemical sensing based on the solute concentration-dependent output signal.