Harnessing water evaporation: flexible generators for next-generation self-powered systems

Abstract

With the escalating demands of miniaturization, flexibility and long-term power stability in portable and wearable electronics, flexible evaporation-driven electricity generators (FEEGs) have emerged as a promising green-energy harvesting platform by exploiting spontaneous energy conversion. Herein, we present a comprehensive review of recent advances in FEEG research. The fundamental generation mechanisms of electric double-layer overlap, streaming potential and evaporation-induced potential at the water–solid interfaces are elucidated. The strategies of functional-material design, structural engineering and interfacial modification are discussed in detail, and the mainstream preparation methods of FEEGs are outlined. Representative applications in self-powered sensing, portable power supply and flexible integrated systems are subsequently reviewed. Finally, considering the challenges of FEEGs in terms of mechanistic understanding, material sustainability, and device durability, we propose future research suggestions including biodegradable functional-material design, corrosion-resistant electrode development, standardized fabrication protocols, and hybrid energy integration systems, to pave the way for large-scale integration and commercialization of FEEGs.