Cathode healing methods for recycling of lithium-ion batteries

Elsevier, Sustainable Materials and Technologies, Volume 22, 2019, e00113, ISSN 2214-9937
Authors: 
Steve E. Sloop, Lauren Crandon, Marshall Allen, Michael M. Lerner, Hanyang Zhang, Weekit Sirisaksoontorn, Linda Gaines, Joon Kim, Myongjai Lee

The electric vehicle and energy storage industries will generate over one-million tons per annum of lithium-ion for recycling in the next decade. There are significant technology gaps in the recovery of lithium-ion battery materials that threaten the sustainability of these industries. Cathode healing is introduced here as a new approach to produce low cost (i.e. < $10/kg), recycled, battery grade electrode material. The soft-chemical treatment non-destructively recycles cathodes. Two examples are shown in this work: LiNi0.5Co0.2Mn0.3O2 and LiNi0.6Co 0.2Mn0.2O2 (NCM 523 and NCM 622). The cathodes were harvested from end-of-life cells and further processed with cathode-healing methods to reproduce recycled electrodes with performance equivalent to the original manufactured baseline material. The so-called healed cathodes were built into 2Ah test cells and compared side-by-side with the baseline. Healed NCM 523 performed like the baseline, recording over 2,100 charge-discharge cycles to reach 80% of original capacity. The cathode healing process was modified to fully recover end-of-life NCM 622. Powder X-ray diffraction and X-ray photoelectron spectroscopy data support the lithium capacity measurements with structural models. These analyses show that cathode healing reverses cation mixing by oxidizing nickel to reproduce well-ordered, high-capacity material. These examples show the technical feasibility and low-cost opportunity for cathode healing to enable sustainability in the electric vehicle and energy storage industries.