Thermodynamically Self‐Assembly Hydration‐Cycle Crystals for Multidimensional Off‐Grid Water‐Energy Nexus

Solar-driven interfacial evaporation (SDIE) technology shows water-energy solution potential but faces industrialization barriers from substrate scalability limits. Here, a regenerative hydrated coordination scaffold (R-HCS) is presented that redefines material design by leveraging water molecules as dynamic structural directors throughout the material lifecycle. Unlike conventional hydrogel/aerogel systems requiring energy-intensive crosslinking (-ΔE = 1-2 orders of magnitude) or freeze-drying processes, R-HCS forms spontaneously through water-mediated self-assembly of calcium sulfate under ambient conditions. Hydration shells drive hierarchical crystallization while fundamentally restructuring hydrogen-bond networks, achieving a 44% reduction in water evaporation enthalpy. The framework demonstrates unique thermal reconfiguration, exhibiting reversible dissociation-reassembly behavior (>100 °C threshold) that enables full material regeneration (performance decay < 5%) using solar thermal energy/waste heat without chemical additives. Crucially, RHCS maintains exceptional ligand stability even when utilizing natural seawater. As proof-of-concept, an R-HCS integrated passive evaporation module achieves 77.2% water recovery under 1 sun irradiation, coupled with 30 °C thermal assembly temperature reduction at 1.5 sun intensity. Concurrently, crystallizer units maintain stable 2.31 kg m^-2 h^-1 evaporation rates in 3.5 wt% brine. This water-centric design paradigm establishes a new class of adaptive materials where solvent-solute interactions become the driving force for circular water-energy systems, potentially redefining sustainable infrastructure for off-grid regions.