Solar-driven ultrafast lithium extraction from low-grade brine using microfluidics-mediated vortex in scalable electrochemical reactors

• Spiral microstructures were designed to enhance mass transfer by forced vortex. • Li extraction rate was greatly increased by the spiral-microstructured reactor. • An off-grid solar power system was demonstrated to drive the SMER to extract Li. • TEA results show a production cost of $28.55/kg, well below market price ($70.99/kg). Electrochemical lithium (Li) extraction from low-grade salt lake brine, when powered by off-grid renewables, represents a potential approach to meeting the substantially increasing demand for battery-grade Li 2 CO 3 . However, this technology has been drastically challenged by the low extraction rate and high production cost, largely due to the lack of research on reactor engineering and system scale-out. Herein, we rationally designed a scalable spiral-microstructured electrochemical reactor (SMER) to accomplish ultrafast and economical Li extraction under harsh brine conditions by virtue of significantly accelerated mass transfer. We showcased that the SMER was stably operated at a Li extraction rate over 5.6 times as much as that of state-of-art devices, and could be up-scaled for commercial production of battery-grade Li 2 CO 3 driven by solar cells. This work lays the ground for sustainable Li extraction from remote low-grade salt lake brine and can be readily applied to more minable Li reserves/resources.