Optimized purification methods for metallic contaminant removal from directly recycled Li-ion battery cathodes.

Autor: Fink K; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States., Gasper P; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States., Major J; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States., Brow R; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States., Schulze MC; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States., Colclasure AM; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States., Keyser MA; National Renewable Energy Laboratory, Alliance for Sustainable Energy, LLC, Golden, CO, United States.
Jazyk: angličtina
Zdroj: Frontiers in chemistry [Front Chem] 2023 Feb 08; Vol. 11, pp. 1094198. Date of Electronic Publication: 2023 Feb 08 (Print Publication: 2023).
DOI: 10.3389/fchem.2023.1094198
Abstrakt: Metallic contaminants pose a significant challenge to the viability of directly recycling Li-ion batteries. To date, few strategies exist to selectively remove metallic impurities from mixtures of shredded end-of-life material (black mass; BM) without concurrently damaging the structure and electrochemical performance of the target active material. We herein present tailored methods to selectively ionize two major contaminants-Al and Cu-while retaining a representative cathode (LiNi 0.33 Mn 0.33 Co 0.33 O 2 ; NMC-111) intact. This BM purification process is conducted at moderate temperatures in a KOH-based solution matrix. We rationally evaluate approaches to increase both the kinetic corrosion rate and the thermodynamic solubility of Al 0 and Cu 0 , and evaluate the impact of these treatment conditions on the structure, chemistry, and electrochemical performance of NMC. Specifically, we explore the impacts of chloride-based salts, a strong chelating agent, elevated temperature, and sonication on the rate and extent of contaminant corrosion, while concurrently evaluating the effects on NMC. The reported BM purification process is then demonstrated on samples of "simulated BM" containing a practically relevant 1 wt% concentration of Al or Cu. Increasing the kinetic energy of the purifying solution matrix through elevated temperature and sonication accelerates the corrosion of metallic Al and Cu, such that ∼100% corrosion of 75 μm Al and Cu particles is achieved within 2.5 hr. Further, we determine that effective mass transport of ionized species critically impacts the efficacy of Cu corrosion, and that saturated Cl - hinders rather than accelerates Cu corrosion by increasing solution viscosity and introducing competitive pathways for Cu surface passivation. The purification conditions do not induce bulk structural damage to NMC, and electrochemical capacity is maintained in half-cell format. Testing in full cells suggests that a limited quantity of residual surface species are present after treatment, which initially disrupt electrochemical behavior at the graphite anode but are subsequently consumed. Process demonstration on simulated BM suggests that contaminated samples-which prior to treatment show catastrophic electrochemical performance-can be recovered to pristine electrochemical capacity. The reported BM purification method offers a compelling and commercially viable solution to address contamination, particularly in the "fine" fraction of BM where contaminant sizes are on the same order of magnitude as NMC and where traditional separation approaches are unfeasible. Thus, this optimized BM purification technique offers a pathway towards viable direct recycling of BM feedstocks that would otherwise be unusable.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(© Alliance for Sustainable Energy, LLC. This work is authored by Kae Fink, Paul Gasper, Joshua Major, Ryan Brow, Maxwell C. Schulze, Andrew M. Colclasure, and Matthew A. Keyser, and was produced by Alliance for Sustainable Energy, LLC under contract No. DE-AC36-08GO28308 with the U.S. Department of Energy.)
Databáze: MEDLINE
Externí odkaz: