Room-temperature relithiation of chemically delithiated LMFP cathode materials as a model for direct recycling
Year: 2026
Type: preprint
Abstract: Room-temperature direct relithiation is an attractive strategy for the regeneration of olivine-type cathode materials, but its applicability to LiMn 0.6 Fe 0.4 PO 4 (LMFP) remains largely unexplored. Here, chemically delithiated LMFP powders were used as model materials to evaluate the feasibility and limitations of direct regeneration under mild conditions. Different delithiation levels were obtained using Ferric nitrate or Nitronium tetrafluoroborate as oxidizing agents, enabling selective oxidation of Fe 2+ or combined oxidation of Fe 2+ and Mn 2+ depending on the oxidizing strength. The structural and redox evolution from pristine to delithiated and relithiated states was followed by X-ray diffraction, X-ray absorption spectroscopy, Mössbauer spectroscopy, Raman spectroscopy, and electrochemical testing. Relithiation was carried out at room temperature using lithium iodide in organic media, including acetonitrile and ethanol. The results show that LMFP can be efficiently relithiated when lithium loss is mainly associated with Fe 2+ oxidation, with substantial recovery of the olivine structure and electrochemical activity. However, higher delithiation levels involving Mn oxidation lead to incomplete regeneration, likely due to manganese dissolution and irreversible local structural changes. These findings demonstrate that LMFP cannot be considered as a simple extension of LFP in direct recycling processes. Instead, manganese-containing olivine cathodes require specific regeneration strategies adapted to their redox chemistry and degradation pathways. Studies on real end-of-life LMFP electrodes will be required to validate the conclusions obtained from these model materials.
Source: ChemRxiv
Language: English
Subfield: Metals and Alloys
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213972342