Triboelectric Nanogenerators Based on Fluid Medium: From Fundamental Mechanisms toward Multifunctional Applications

Fluid-based triboelectric nanogenerators (FB-TENGs) are at the forefront of promising energy technologies, demonstrating the ability to generate electricity through the dynamic interaction between two dissimilar materials, wherein at least one is a fluidic medium (such as gas or liquid). By capitalizing on the dynamic and continuous properties of fluids and their interface interactions, FB-TENGs exhibit a larger effective contact area and a longer-lasting triboelectric effect in comparison to their solid-based counterparts, thereby affording longer-term energy harvesting and higher-precision self-powered sensors in harsh conditions. In this review, various fluid-based mechanical energy harvesters, including liquid-solid, gas-solid, liquid-liquid, and gas-liquid TENGs, have been systematically summarized. Their working mechanism, optimization strategies, respective advantages and applications, theoretical and simulation analysis, as well as the existing challenges, have also been comprehensively discussed, which provide prospective directions for device design and mechanism understanding of FB-TENGs. Fluid-based triboelectric nanogenerators (FB-TENGs) are emerging energy technologies with improved effective contact area and prolonged triboelectric effect compared to their solid-based counterparts. This review summarizes the working mechanism and optimization strategies of various FB-TENGs, including liquid-solid, gas-solid, liquid-liquid, and gas-liquid TENGs. Their respective advantages, applications, and challenges have been also systematically discussed, offering guidance for designing high-performance FB-TENGs.image