Structurally engineered solvent-free LiFePO4 electrodes via hot-pressing with efficient ion transport pathways for lithium extraction from brine

The development of high-mass-loading electrodes with robust ion transport characteristics is crucial for efficient electrochemical lithium extraction from brine. Herein, we report a solvent-free hot-pressing strategy to fabricate structurally engineered LiFePO 4 electrodes with enhanced electrochemical performance and mechanical stability. By integrating etched titanium foil as a current collector and multi-walled carbon nanotubes as a conductive additive, a three-dimensionally interconnected porous structure was formed, enabling accelerated ion diffusion and improved structural integrity. Micro-CT and Avizo-based analysis revealed that the dry press-coated electrodes possess higher porosity, lower tortuosity and more connected ion channels compared to conventional slurry-coated electrodes. Electrochemical tests demonstrated a significantly higher lithium-ion diffusion coefficient and lower charge transfer resistance of the dry press-coated electrodes. Under optimized conditions, the dry press-coated electrodes, possessing a mass loading of 19.4 mg·cm −2 , delivered a lithium extraction capacity of 4.13 mg·cm −2 with a purity of 93.91% over 15 cycles in simulated Uyuni brine. This work establishes a scalable hot-pressing method and elucidates its fundamental physicochemical advantages for lithium-selective electrochemical separation.