Scalable Direct Recovery of Spent LiFePO4 with a Redox-Mediated Flow Cell

The rapid advancement and widespread adoption of lithium-ion batteries (LIBs), particularly lithium iron phosphate (LFP) batteries, have led to significant environmental challenges due to their disposal. Traditional recycling techniques, such as pyrometallurgical and hydrometallurgical processes, are energy-intensive, costly, and environmentally detrimental. LIB capacity deterioration primarily occurs through damage to the active material (e.g., irreversible phase transitions, particle cracking) and loss of carrier ions, with the latter being more common in temperature-controlled systems used in large-scale applications. This study introduces a novel electrochemical-based redox-mediated approach for the direct recovery of spent LFP cathode materials by restoring lost lithium (carrier ion). The sustainable aqueous flow system operates on a large scale at low cost, utilizing additional lithium sources (LiOH) and redox-active mediators (low-cost and stable organic molecules), stable operation at a current density of at least 10 mA/cm2. Characterization of the recovered LFP (r-LFP) confirms its electrochemical properties and structural integrity are comparable to standard LFP, with a specific capacity near to theoretical capacity, good capacity retention, and rate performance. This redox-mediated recovery method offers significant advantages over conventional recycling approaches, including higher current densities, greater material loading, and reduced reaction times. This cost-effective and environmentally friendly technique provides a sustainable solution for the valorization of end-of-life LIBs, contributing to a circular economy and reducing the environmental impact of battery waste. Figure 1