Electrosorption Theoretically Outperforms Nanofiltration and Electrodialysis for Direct Lithium Extraction from Brines

The demand for lithium (Li) is rapidly growing as Li-ion batteries play an increasingly important role in achieving the global “net-zero emissions”. Direct lithium extraction (DLE) technologies have emerged as a transformative technology for efficiently and sustainably producing Li products from brine. While numerous studies have focused on improving Li+/Mg2+ selectivity, proper Li+ concentration before carbonation is largely overlooked. In this critical review, we examine the critical performance requirements for DLE, focusing on active-control DLE technologies where external fields actively regulate extraction, including nanofiltration, electrodialysis, and electrosorption. Although all three technologies can achieve high Li+/Mg2+ selectivity with the development of advanced materials, electrodialysis and electrosorption are capable of simultaneously separating and concentrating Li+, making them more promising for realizing a real DLE process compared to nanofiltration. Furthermore, we compare the economic and environmental performance of these technologies. While the levelized cost of lithium carbonate for electrosorption (5,400 USD ton–1) is comparable to nanofiltration and electrodialysis, its global warming potential (−3911 kg CO2 eq) is markedly lower. Thus, electrosorption theoretically emerges as the most promising candidate for achieving a truly environmentally sustainable DLE process. Finally, we discuss the key challenges to industrial deployment of ES and outline potential strategies for their resolution.