Freeze-dried low-curvature porous structure iron phosphate electrodes for efficient lithium extraction from brine

This study explores the optimization of electrodes for lithium extraction from salt lake brine, particularly focusing on increasing extraction capacity by utilizing thick electrodes. However, thick electrodes present challenges such as limited diffusion of high-salinity, viscous brine to the electrode interface, resulting in uneven distribution and reduced lithium extraction efficiency. To address these challenges, a novel low-curvature porous structure electrode was designed using a freeze-drying method (FD-LFP). This design increases the effective surface area and provides more active sites for lithium storage, while also optimizing the distribution of active sites and ion diffusion paths to reduce transport resistance and lower overpotential. When evaluated for lithium extraction from simulated Atacama brine, the FD-LFP electrodes with graphite-coated paper as the current collector (FD-LFP-GCP) demonstrated superior performance, achieving a lithium extraction capacity of 40.45 mg/g, a lithium extraction areal capacity of 0.906 mg/cm 2 , and a lithium-ion purity of 92.04 % with an energy consumption of 0.422 Wh/mol. The novel design thus offers significant potential for the widespread application of electrochemical lithium extraction technology by effectively addressing the challenges associated with thick electrodes.