Simultaneous Fresh Water Collection and Li⁺ Selective Adsorption Enabled by A Salt‐Resistant Separated Solar Evaporator

Abstract

Abstract Solar‐driven interfacial evaporation (SIE) of brine may solve the fresh water shortage issue but suffers from salt‐fouling. Meanwhile, adsorption can extract valuable lithium (Li) from brine but is hampered by low adsorption capacity/rate, additional energy input and low selectivity, etc. Here, as a proof‐of‐concept, the design of a separated solar evaporator (S‐evaporator) is reported for simultaneously efficient fresh water collection and Li + selective adsorption by SIE of brine, accomplishing their complementation using only sunlight. The S‐evaporator consists of a tilted n‐shaped H 2 TiO 3 ‐modified fabric and a photothermal sheet on it. The superhydrophilic fabric transports brine to the photothermal sheet and provides affluent sites for Li + adsorption. The photothermal sheet promotes SIE and enhances Li + adsorption by significantly increasing the fabric's temperature. Consequently, simultaneous fresh water collection and Li + selective adsorption are realized by the S‐evaporator. Under 1 kW m −2 illumination, the S‐evaporator shows long‐term stable evaporation rate (1.51 kg m −2 h −1 ) for 20 wt% brine, high Li + adsorption capacity (20.09 mg g −1 ), good Li + adsorption selectivity from real brine and good cycle stability. The S‐evaporator has great application potential for efficiently extracting fresh water and Li + from brine as demonstrated by the large SIE setup in real outdoor conditions.