The current trend in the electric vehicle industry to shift back from Li(Ni,Co,Mn)O2 (NCM) to low-cost LiFePO4 (LFP) in batteries (47 % market share predicted by 2026[1]) poses a challenge for recyclers. While NCM batteries contain valuable materials such as cobalt and nickel, the profitability of recycling LFP batteries using the conventional recycling processes (i.e., pyro- and hydrometallurgy) is very low.[2] Direct recycling is an emerging approach that can be particularly interesting for low-cost battery chemistries. Direct recycling offers a crucial advantage by preserving materials in their original structure, avoiding the common practice of “downcycling” into precursors (such as metal salts).
In this study, LFP/graphite pouch cells are opened using shock wave technology. By combining this technique with physical sorting and sieving, different black mass fractions were obtained. The results of in-depth characterization (incl. ICP-OES, SEM, carbon content analysis) of black mass fractions obtained by treating LFP/graphite pouch cells with shock wave technology (combined with physical sorting and sieving) demonstrate that a pre-concentration into LFP- and graphite-rich fractions is possible. In addition, XRD results reveal that the original material structure of LFP and graphite is preserved during the recycling process that enables a direct recycling route (= direct re-use of the recycled materials in the manufacturing of new batteries). Preliminary experiments using the heavy liquid separation approach indicate that this technique might be suitable for further post-purification of the fractions (e.g., removal of copper impurities that can be detrimental for the cell performance, in particular when they are present in the cathode). Homogeneous electrode coatings were obtained when reintegrating the purified recycled graphite-rich fraction in the anode production. Further work will now focus on the electrochemical testing of the anode with recycled material, optimizing the post-purification step (for graphite- and LFP-rich fractions) and the regeneration of the active materials (i.e., relithiation of LFP).

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[1] S. Korus, ARK Investment Management LLC, 2022, https://ark-invest.com/articles/analyst-research/lithium-iron-phosphate-batteries/ (accessed in January 2024).
[2] N. Willing, Argus Media, 2023, https://www.argusmedia.com/en/news/2513976-nmc-to-lfp-transition-poses-battery-recycling-challenge/ (accessed in January 2024).