Bioinspired Salt Absorption‐Secretion Strategy Unlocking Solar Evaporation‐Driven Selective Lithium Extraction From Salt‐Lake Brines

ABSTRACT The surging global demand for lithium underscores the critical need for sustainable extraction technologies, particularly from salt‐lake brines, which hold the majority of global lithium reserves. However, conventional solar‐driven evaporation systems suffer from salt deposition, limited selectivity, and poor stability. Here, inspired by the salt management mechanism of Avicennia marina , an innovative solar evaporation system with spatially decoupled salt adsorption‐secretion architecture is developed, which enables highly selective lithium adsorption from salt‐lake brines. The core of this system is a spherical photothermal evaporator with multi‐channel water pathways, designed to spatially separate lithium capture on the evaporator surface from the crystallization of competing salts at remote sites. Driven by solar evaporation, this unique design achieves an excellent lithium uptake capacity of 29.4 mg g −1 and maintains stable operation in high‐salinity brine (300 g L −1 ). Field tests demonstrate exceptional lithium selectivity ( S Li/Mg of 272.8, S Li/Na of 236.2), substantially surpassing conventional evaporators ( S Li/Mg of 10–150, S Li/Na of 20–120). The system directly produced battery‐grade Li 2 CO 3 (>99.7% purity) from natural brines and exhibited outstanding reusability, retaining 92.9% resource recovery efficiency over 40 operational cycles. This work offers a scalable and sustainable solar‐powered strategy for lithium extraction.