Continuous Recovery of Spent LiFePO₄ via Ascorbic Acid Based Redox Flow Battery

The direct recycling of spent LiFePO₄ is essential for building a sustainable circular economy for lithium-ion batteries, yet conventional methods suffer from high energy consumption and environmental pollution. Here, we develop a continuous redox flow battery using regenerable ascorbic acid as a redox mediator for efficient ambient-temperature relithiation. The electrochemical regeneration of ascorbic acid enables a near-closed-loop process with minimal reagent consumption. The regenerated LiFePO₄ achieves a specific capacity of 123.6 mAh/g at 0.5 C, comparable to spent LiFePO₄, and achieve a capacity restoration efficiency of 44.3%. Structural and elemental analyses confirm successful restoration of the crystal lattice and lithium content. This work provides a green, economical, and scalable strategy for direct recycling of spent LiFePO₄, demonstrating strong potential for industrial-scale battery reclamation.