A simple fast-response, polarity-switchable self-powered sensor based on a Ti-based mesh via hybrid triboelectric and streaming-potential effects

A self-powered sensor based on a bare Ti mesh with polarity-switchable output • Combined experimental and COMSOL simulation validates hybrid triboelectric and streaming-potential mechanism. • Demonstrates multi-parameter sensing: flow velocity, volume, ionic solutions, and natural water types • Higher-valence cations (Al 3+  > Mg 2+  > Na + ) produce significantly enhanced signals. The growing demand for standalone self-powered sensing systems is driving significant interest in developing devices that can harvest energy from ambient moisture and natural water sources while simultaneous providing sensing capabilities. This study presents a cost-effective, industrially scalable self-powered sensor based on a simple Ti-based mesh integrated within a pressure-adjustable container. The electrical output of this device can be rapidly polarity-switched merely by toggling the water flow through the Ti-based mesh, without any surface modification or external energy input. Notably, the device demonstrates multi-parameter sensing capabilities, enabling detection of water flow velocity, flow volume, ionic solutions of varying valences and concentrations, and even different types of natural water. The underlying mechanisms are elucidated through combined experimental and computational analyses, revealing that the electrical signals originate from hybrid triboelectric and streaming-potential effects. This work establishes a design paradigm for high-performance, Ti-based self-powered sensors with polarity-switchable characteristics, offering promising applications in environmental monitoring and water quality assessment.