Recent advances in multistage solar distillation are promising for the sustainable supply of freshwater. However, significant performance degradation due to salt accumulation has posed a challenge for both long-term reliability of solar desalination and efficient treatment of hypersaline discharge. Here, inspired by a natural phenomenon, thermohaline convection, we demonstrate a solar-powered multistage membrane distillation with extreme salt-resisting performance. Using a confined saline layer as an evaporator, we initiate strong thermohaline convection to mitigate salt accumulation and enhance heat transfer. With a ten-stage device, we achieve record-high solar-to-water efficiencies of 322%–121% in the salinity range of 0–20 wt % under one-sun illumination. More importantly, we demonstrate an extreme resistance to salt accumulation with 180-h continuous desalination of 20 wt % concentrated seawater. With high freshwater production and extreme salt endurance, our device significantly reduces the water production cost, paving a pathway toward the practical adoption of passive solar desalination for sustainable water economy.

多级太阳能蒸馏的最新进展有望实现淡水的可持续供应。然而，由于盐积累导致的性能显着下降，对太阳能海水淡化的长期可靠性和高盐排放的有效处理提出了挑战。在这里，受温盐对流这一自然现象的启发，我们展示了具有极高耐盐性能的太阳能多级膜蒸馏。使用受限盐层作为蒸发器，我们启动强温盐对流，以减轻盐积聚并增强传热。通过十级装置，我们在 0-20 wt% 的盐度范围内，在一个太阳光照下，实现了创纪录的 322%-121% 的太阳能-水效率。更重要的是，我们通过对 20 wt% 浓缩海水进行 180 小时连续淡化，证明了对盐积累的极端抵抗力。我们的设备具有高淡水产量和极高的耐盐性，可显着降低水生产成本，为实际采用被动式太阳能海水淡化以实现可持续水经济铺平了道路。