Solar-enhanced lithium extraction from brines: strategies and applications

The global demand for lithium resources is continuously increasing, making the extraction of lithium (Li⁺) from brines a topic of widespread research interest. Traditional methods for extracting Li⁺ from brines are often hindered by high energy consumption, time-consuming extraction processes, and sluggish kinetics. Solar-enhanced lithium extraction (SEIE) technology utilizes green sources of energy to achieve a high water evaporation rate, serving as a driving force for the efficient capture and enrichment of Li⁺ from brines. Recently, significant progress has been made in the SEIE system, highlighting the need to review and summarize the strategies and applications of current photothermal materials (PMs) for sustainable Li⁺ extraction. This review begins by outlining the construction strategies of PMs to achieve high photothermal conversion efficiency and a high water evaporation rate. It then summarizes the engineering approaches of PMs in the SEIE system for Li⁺ extraction, including Li⁺ selective adsorption PMs and Li⁺ selective separation PMs, with a detailed discussion on their underlying mechanisms, design principles, and practical applications. Finally, we provide perspectives on the design of next-generation PMs in the SEIE system and propose strategies to enhance their long-term stability for practical lithium resource harvesting. In summary, this review not only systematically analyzes Li⁺ recovery from various brines but also offers actionable guidelines for advancing SEIE technology toward industrial-scale applications.