Ultrafast and efficient recovery of valuable metals from spent LiCoO2 cathode via organic ferrous assisted reductive ammonia leaching

Leaching of LCO using ferrous glycinate under ammonia leaching. • Achieved a high leaching efficiency for LCO. • Guaranteed the absence of non-target impurities in the final product. Efficient and environmentally sustainable recovery of valuable metals from spent lithium cobalt oxide (LiCoO 2 , LCO) cathodes is crucial for the lithium-ion batteries recycling. While ammonia leaching offers a promising pathway for green closed-loop recycling, its conventional application suffers from slow kinetics. To address this limitation, this study introduced ferrous glycinate (Gly-Fe) as a novel reductant, alongside FeCl 2 for comparison, into an NH 3 -based system, which enabled ultra-rapid reductive dissolution of LCO. A systematic investigation of key parameters, including temperature, ammonia concentration, and Fe/Co molar ratio, revealed Gly-Fe’s superior performance. It was found that nearly complete leaching efficiencies of Li + (∼100.0%) and Co 2+ (96.2% ± 2.1%) was achieved within just 60 min using Gly-Fe. In contrast, FeCl 2 attained Li + leaching of ∼ 100.0% but only 83.5% ± 2.6% for Co 2+ within 30 mins under comparable conditions, highlighting the kinetic advantage and effectiveness of the glycine-based complex. Noticeably, Fe 2+ from both reagents precipitated spontaneously in the alkaline ammonia medium without additional additives, facilitating the direct recovery of high-purity leach products. This approach preserved the intrinsic purity advantages of ammonia leaching while accelerating metal extraction rates and significantly enhancing metal recovery rates, thereby establishing a solid foundation for the development of efficient closed-loop recycling for spent lithium-ion batteries. Download: Download high-res image (107KB) Download: Download full-size image