A scaling-resistant multilayer hanging system for efficient solar evaporation-assisted lithium recovery with enhanced...

Lithium recovery from salt-lake brines offers a potential route to alleviate strategic lithium shortages driven by surging global demand. Solar evaporation-assisted lithium adsorption (SELA) has been developed to enhance this process by harnessing solar energy to promote endothermic adsorption and interfacial ion enrichment. However, conventional SELA architectures are fundamentally constrained by sluggish mass transfer and interfacial salt scaling in floating configurations that rely on passive capillary transport. Herein, we report a SELA hanging system that overcomes these physical limitations by establishing a gravity-driven thin-film convection regime. The system integrates a carbon fiber cloth-based photothermal layer with a core-shell polyacrylonitrile/titanium-based lithium-ion sieve@cellulose acetate adsorption layer, suspended between a higher-level supply tank and a lower-level collection tank. This hanging configuration creates a "pre-activated ionic environment", referring to the heated, concentrated, and high-flux brine generated by solar evaporation before entering the adsorption layer, which provides a thermally activated and mass-transfer-enhanced feed for subsequent Li⁺ capture. Under 1-sun irradiation (1 kW m^-2), the SELA hanging system delivers a Li⁺ adsorption capacity of 27.6 mg g^-1 for 6 h, a 206.7% enhancement relative to dark conditions. When tested in simulated brine, the hanging architecture maintained exceptional stability with no visible scaling, whereas the floating model suffered a 19.9% performance decay. This work establishes a scaling-resistant and energy-efficient strategy for lithium recovery from salt-lake brines resources.