Resynthesis and Electrochemical Performance of Ncm111 Using Ultrasound-Assisted Leachate From Spent Lithium-Ion Battery Cathodes

The widespread use of lithium-ion batteries (LIBs) led to a substantial accumulation of spent cathode materials, creating an urgent need for environmentally sustainable recycling methods that address both ecological concerns and the recovery of critical metals. A novel strategy integrating ultrasound-assisted deep eutectic solvent (DES) leaching and urea-assisted co-precipitation for the regeneration of high-performance LiNi1/3Co1/3Mn1/3O2 (NCM111) cathodes from spent LiCoO2 was developed. The results revealed that the transition metal-to-urea molar ratio critically governs the structural and electrochemical properties of regenerated materials. An NCM111 sample with an optimized transition metal-to-urea ratio of 1:2 had an ordered layered structure (I(003)/I(104) = 1.336), uniform spherical secondary particles (1–3 µm), and minimal cation mixing. These structural advantages translated into exceptional electrochemical performance, including an initial Coulombic efficiency of 84.84 %, 96.13 % capacity retention after 30 cycles, low charge-transfer resistance (37.26 Ω), and enhanced redox reversibility (ΔEp = 0.21 V). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) further confirmed the superior interfacial kinetics and reaction reversibility of the optimised sample.