Recycling Ni-Rich NCM Cathode Materials From Spent Li-Ion Batteries as Efficient Electrocatalyst for Urea Oxidation

Abstract

The burgeoning electric vehicle industry has intensified the demand for high-energy Ni-Co-Mn (NCM) cathodes, yet their end-of-life management remains a critical environmental challenge. Here, we show that spent high-Ni NCM (LiNi_0.92Co_0.05Mn_0.03O₂) cathode materials can be directly upcycled into robust urea oxidation (UOR) catalysts. A facile solvent-only delamination converts discarded cathodes into printable inks; drop-casting onto carbon paper yields electrodes delivering ~10 mA mg⁻¹ at 1.50 V versus RHE. Operando synchrotron X-ray diffraction reveals that K⁺ ions spontaneously intercalate into Li-deficient interlayers, expanding the (003) interplanar spacing from 4.7 to 7.1 Å. An electrochemical–chemical (E–C) reaction mechanism is proposed, in which Ni³⁺ species are electrochemically generated on the catalyst surface and are then chemically reduced during urea oxidation, a process promoted by K⁺ intercalation. This lattice-engineered redox process stabilizes the layered framework and suppresses metal dissolution, ensuring >24 h of continuous urea electrolysis. The work offers a circular economy solution for battery waste treatment while providing atomistic design principles for next-generation, earth-abundant environmental catalysts.