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

Abstract 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.