One-Pot Regeneration and Remanufacturing of Spent LiNi_(1-x-y)Mn_xCo_yO_2 Materials with Organic Acid

摘要

The abundant end-of-use lithium-ion batteries necessitate the recovery of precious transition metals. In this article, we use a green, one-pot process to recover and remanufacture the spent Li-Ni_(1-x-y)Mn_xCo_yO_2 (NMC) cathode materials. The LiNi_(0.5)Mno_(0.3)Co_(0.2)O_2 (NMC532) was directly recycled through a combined leaching and precipitation process using oxalic acid in recyclable ethanol as leaching solvent. The overall element recycling efficiency was up to 97.3%, and the energy consumption can be reduced by ~11.4% with reduced reaction time compared to that in the hydrometallurgical method using strong acid. In addition to the transition metals, the lithium was also recovered to regenerate NMC532, which displayed excellent electrochemical performance with an initial specific discharge capacity of 165.3 mA h/g and a Coulombic efficiency of 83.6%. As high as 87.1% capacity was retained after 300 cycles at 1/3 C. In parallel, the spent NMC532 was also successfully remanufactured into NMC811 by adjusting the element stoichiometric ratio, which showed a high initial capacity of 184.1 mA h/g along with a high capacity retention. The usage of environment friendly organic acid and recyclable solvent provides a low-cost technology to recover and remanufacture NMC materials in lithium-ion batteries.