Achieving “Ion Diode” Salt Resistance in Solar Interfacial Evaporation by a Tesla Valve‐Like Water Transport Structure

Abstract Salt deposition is a disturbing problem that limits the development of passive solar‐driven interfacial evaporation. Inspired by the passive fluid control mechanism of the Tesla valve, a novel solar evaporator is proposed with a Tesla valve‐like water transport structure to prevent salt accumulation at the evaporation interface. A unique “ion diode” salt resistance of this evaporator is significantly achieved by optimizing the two asymmetric water transport structures, consisting of one Tesla valve‐like side and one wide‐leg side, which establish a reverse‐suppressing and forward‐accelerating water transport channel. In contrast to the limited ion migration of the typical symmetric solar evaporator, such a channel caused by the water/salt ions transport difference between two water supply structures, reinforces the water/salt ions supply on the wide‐leg side, thus leading to an apparent unidirectional salt ions migration from the wide‐leg side to bulk water through the Tesla valve‐like side. Consequently, an evaporation rate of 3.25 kg m −2 h −1 and a conversion efficiency of 83.27% under 2 suns are achieved in 16 wt% NaCl solution. The development of the Tesla Valve‐like evaporator provides a new perspective for solving salt deposition and realizing scalable applications of solar‐driven interfacial evaporation.