With the depletion of fossil energy, the demand for lithium (Li) has globally surged, and the extraction of Li must be environmentally and socially responsible for a sustainable future. Solar pool-based Li extraction shows promise but is limited by climate-dependent evaporation rates and long production cycles. While closed systems for steam energy recovery offer improvements, accumulated condensation often reduces light transmittance and efficiency. In this study, we report a superhydrophilic hydrogel coating (DOH coating) that can be coated on the top of a closed system, showing broad application prospects in salt lake Li enrichment. The DOH coating, featuring abundant hydrogen-bond functional groups and synergistic supramolecular interactions, exhibited unique properties, including superhydrophilicity (WCA < 5°), high light transmittance (91.51% ± 0.03%, n = 5), and low haze (0.74% ± 0.02%, n = 5). Furthermore, a brine concentration and collection device (the closed DOH system) was constructed, which achieved 81.6% heat recovery efficiency and an evaporation rate that is 5.4 times that of open systems even at 0 °C. It significantly improved the concentration efficiency of brine by 12 times and realized the synchronization of Li concentration and clean freshwater collection from salt lakes.