A Self-Powered pH Sensing Method Based on a Triboelectric Nanogenerator: An Innovative Application in Marine Ranch...

To achieve intelligent aquaculture and ensure environmental health, water quality monitoring is indispensable in marine ranching. However, the energy supply for widely deployed sensors remains a critical challenge. Self-powered sensing technology is one of the core solutions to address this bottleneck. In this research, a capsule-structured, solid-solid/solid-liquid mixed-mode triboelectric nanogenerator (TENG) is proposed, which addresses the limitations of the existing TENG technology in marine environments. The proposed TENG collects wind and wave energy by coupling solid-solid contact electrification with the bilayer effect at the solid-liquid interface under complex marine conditions. A theoretical model of triboelectric energy conversion and solid-liquid pH sensing is developed. Additionally, the TENG self-powered sensing structure is optimized to improve its performance for pH monitoring under a range of conditions in marine ranches. The experimental results demonstrate that the capsule-type dual-mode TENG (CD-TENG) achieves an open-circuit voltage of 50 V and a short-circuit current of 25 μA under optimal conditions. The peak power density of 0.35 W/m² enables sustained operation of low-power microelectronics, which is beneficial for real-time water quality monitoring in marine ranching.