An Integrated Recycling Strategy for Selective Lithium Separation and Reconstruction of Mixed Spent Cathodes for Water Oxidation

ABSTRACT

Sustainable recycling of spent lithium‐ion batteries (LIBs) is critical for low‐carbon development and responsible resource utilization. Here, we report a green recycling strategy that simultaneously processes spent ternary (s‐NCM) and spent lithium iron phosphate (s‐LFP) cathode materials with diverse compositions, enabling compatibility with a wide range of feedstocks. An electrochemical pre‐delithiation step achieves highly selective lithium recovery with efficiencies above 99% and negligible transition‐metal loss (<0.15%). The delithiated residues are subsequently reconstructed into oxygen evolution reaction (OER) catalysts through a low‐cost, low‐energy process without external metal additives. Owing to the intrinsic Ni–Fe synergy derived from s‐NCM and s‐LFP, the resulting NiFe (rec‐NCM955/LFP) pre‐catalyst exhibits outstanding OER performance, delivering a low overpotential of 234 mV at 10 mA·cm ⁻² , a small Tafel slope of 28.4 mV·dec ⁻¹ , and stable operation at 500 mA·cm ⁻² for 200 h in an anion exchange membrane water electrolyzer. Economic and environmental analyses further confirm the scalability and industrial feasibility of this approach. This work offers an integrated and practical solution for selective lithium recovery and direct cathode upcycling, advancing circular LIB recycling and green hydrogen production.