Design of self-righting steam generators for solar-driven interfacial evaporation and self-powered water wave detection

Solar-driven interfacial evaporation has attracted growing attention as an emerging and sustainable technology for wastewater purification and desalination. Tremendous research efforts have been dedicated to developing interfacial steam generators that can operate under realistic weather conditions such as changing solar intensity, water salinity, air flow and humidity, yet the effects of water waves have been largely neglected. Herein, we develop the first ever tumbler-shaped steam generator to improve the floating stability of interfacial steam generators. Apart from the good water evaporation rate of ∼1.3 kg m−2 h−1 under one sun in both freshwater and seawater, the tumbler-shaped monolithic steam generator demonstrates outstanding wave-piercing, anti-overturning and self-righting behavior with good structural durability in typical waves of open water. Gratifyingly, further integration of the tumbler-shaped steam generator with a triboelectric nanogenerator enables detection of several water wave parameters (frequency, height, velocity and wavelength) in real-time with high sensitivity. This work provides design protocols not only for developing stable interfacial steam generators for solar-driven water purification and desalination, but also for scaling-up clean water production in open water and engineering self-powered water wave detection, forecast, and blue energy harvest systems.