A highly efficient and durable solar evaporator based on hierarchical ion‐selective nanostructures

Solar-driven vapor generation technology can directly produce clean water, but existing strategies remain challenging in achieving both high evaporation performance and good salt resistance due to complex water-thermal management. Here, we constructed hydrogel-based hierarchically nanostructured evaporator (HNE) with vertically aligned micro water transportation pathways and water confined ion selective nanochannels. Based on the polarity modified hierarchical structures and umbrella-shaped geometry design, HNEs can achieve high-speed water transfer at low saturated water content to realize efficient heat energy confinement, and provide more heat exchange sites. Consequently, an exciting water evaporation rate of 3.68 kg m(-2) h(-1) and the efficiency of 91.1% were achieved under 1 sun solar radiation. More importantly, the overlapping electrical double layer in the narrow nanochannels endows the ions selectivity of the nanochannel to reject anions, resulting in reliable long-term salt resistance. The ingenious design was creatively confirmed by streaming potential and validated during long-term efficient work.