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

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.