Direct Recycling R&D at the ReCell Center

A case study using spectroscopy and computational modelling for Co speciation in a deep eutectic solvent

Cobalt has a vital role in the manufacturing of reliable and sustainable clean energy technologies. However, the forecasted supply deficit for cobalt is likely to reach values of 150 kT by 2030. Therefore, it is paramount to consider end-of-life devices as secondary resources for cobalt. Electrorecovery of cobalt from leached solutions has attracted attention due to the sustainability of the recovery process over solvent extraction followed by chemical precipitation. Recently, we reported Co electrorecovery from two different cobalt sources (CoCl2·6H2O and CoSO4·7H2O) using ethylene glycol : choline chloride (EG : ChCl) in a 4.5 : 1 molar ratio, leading to higher purity and easier electrodeposition when sulfate was present as an additive. Here, Co2+ speciation is reported for the two EG : ChCl systems depending on the cobalt source using several spectroscopic techniques (e.g. NMR, EPR, FTIR) in combination with molecular dynamics simulations. Monodentate coordination of SO42- to Co2+, forming the tetrahedral [CoCl3(SO4)]3- was observed as the dominant structure in the system containing CoSO4·7H2O, whereas the system comprising CoCl2·6H2O shows a homoleptic tetrahedral [CoCl4]2- as the dominant structure. This resulted in knowledge being gained regarding Co2+ speciation and the correlation with electrochemistry will contribute to the science required for designing safe electrolytes for efficient electrorecovery.

A comprehensive review of emerging technologies for recycling spent lithium-ion batteries

Along with the increasing demand for lithium-ion batteries (LIB), the need for recycling major components such as graphite and different critical materials contained in LIB is also reaching a peak in the research community. Several authors review the different LIB recycling methodologies, including pyro- and hydrometallurgy processes. However, the characteristics, main stages, and achievements of LIB emerging recycling are still missing. This study reviews the diverse emerging approaches for recycling critical materials from spent LIB in the last five years. A classification for emerging recycling technologies is provided, including terms like development stage and eco-friendly status. The main stages of recycling LIB are opening, phase separation, and materials recovery. Among the emerging proposals with the highest industrialization potential are direct recycling techniques due to low costs and simple procedures. Concerning phase separation, froth flotation and ultrasound-assisted methods are discussed. The former divides black mass into pure anodic and cathodic materials, while ultrasonication is employed to physically detach active materials from foils or enhance binder degradation. As to materials recovery, several recent approaches show high recovery efficiency for different elements, mainly in leaching. The use of new organic acids, deep eutectic acids, and some salts are worth noting as leaching agents due to their low environmental impact. In addition, leaching methods assisted by ultrasound and microwave irradiation increase valuable metal recovery, reducing time consumption and the number of leaching reactants. As a part of the hydrometallurgy process, metallic ion purification is performed by solvent extraction and ion exchange, while selective precipitation can be achieved by specific chemical agents or electrochemical processes.

China's electric vehicle and climate ambitions jeopardized by surging critical material prices

The adoption of electric vehicles (EVs) on a large scale is crucial for meeting the desired climate commitments, where affordability plays a vital role. However, the expected surge in prices of lithium, cobalt, nickel, and manganese, four critical materials in EV batteries, could hinder EV uptake. To explore these impacts in the context of China, the world's largest EV market, we expand and enrich an integrated assessment model. We find that under a high material cost surge scenario, EVs would account for 35% (2030) and 51% (2060) of the total number of vehicles in China, significantly lower than 49% (2030) and 67% (2060) share in the base-line, leading to a 28% increase in cumulative carbon emissions (2020-2060) from road transportation. While material recycling and technical battery innovation are effective long-term countermeasures, securing the supply chains of critical materials through international cooperation is highly recommended, given geopolitical and environmental fragilities.

Graphite Flows in the U.S.: Insights into a Key Ingredient of Energy Transition

Demand for graphite will grow with expanding use of lithium-ion batteries in the United States. Much graphite is imported, raising supply chain risks. It is therefore imperative to characterize graphite's sources and sinks. Accordingly, we present the first material flow analysis for natural and synthetic graphite in the U.S. The analysis (for 2018) begins with processed graphite trade and includes graphite production, graphite product trade, manufacturing of end products, end product use, and waste management. It considers 11 end-use applications for graphite, two waste management stages, and three recycling pathways. In 2018, 354 thousand tonnes (kt) of processed graphite were consumed in the U.S., including 60 kt natural graphite and 294 kt synthetic graphite. 145 kt of graphite were traded. Refractories and foundries consumed 56% of natural graphite; 42% of synthetic graphite went into making graphite electrodes. Batteries accounted for 10 and 5% of natural and synthetic graphite consumption, respectively; 78% of total graphite used dissipated into the environment; 22% reached the waste disposal stage of which 71% was landfilled and 29% was recycled; and 59 kt of graphite accumulated in in-use stocks. Recycling more graphite and producing graphite from lignin would favorably influence today's supply chain.

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

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_0.33Mn_0.33Co_0.33O₂; 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 Al⁰ and Cu⁰, 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.

Current Challenges in Efficient Lithium-Ion Batteries' Recycling: A Perspective

Li-ion battery (LIB) recycling has become an urgent need with rapid prospering of the electric vehicle (EV) industry, which has caused a shortage of material resources and led to an increasing amount of retired batteries. However, the global LIB recycling effort is hampered by various factors such as insufficient logistics, regulation, and technology readiness. Here, the challenges associated with LIB recycling and their possible solutions are summarized. Different aspects such as recycling/upcycling techniques, worldwide government policies, and the economic and environmental impacts are discussed, along with some practical suggestions to overcome these challenges for a promising circular economy for LIB materials. Some potential strategies are proposed to convert such challenges into opportunities to maintain the global expansion of the EV and other LIB-dependent industries.

Exploring potential opportunities for the efficient development of the cobalt industry in China by quantitatively tracking cobalt flows during the entire life cycle from 2000 to 2021

Owing to its key role in high-tech industry and clean energy technology, cobalt has been regarded as a critical material in many countries. In this paper, material flow analysis was used to quantitatively track cobalt material flows in China throughout the entire life cycle from 2000 to 2021. Based on data pertaining to cobalt commodity trade, cobalt loss during raw material processing, and recovered cobalt, we analysed the actual cobalt consumption in China. During the study period from 2000 to 2021, the main findings were as follows: (1) China's cobalt raw material imports accounted for 84.7% of the total raw materials acquired, while the export of cobalt-containing end products amounted to 32.6% of the total production. (2) China's cumulative net import of all cobalt commodities reached 561 kt, and battery products accounted for 73.3% of the total cobalt consumption. (3) China recovered 77 kt of cobalt from end-of-life products, while 327 kt of cobalt was not recovered. (4) The cumulative cobalt loss during raw material processing reached 288 kt, with the highest loss occurring in refining (51.0%), followed by manufacturing and fabrication (26.5%), beneficiation (12.3%), and ore mining (10.2%). The overall utilization efficiency of cobalt was 73.8% throughout the entire life cycle. (5) China's actual cobalt consumption reached 497 kt, accounting for 51.9% of the apparent cobalt consumption. Moreover, 61.1% of the cobalt products produced in China was consumed domestically, while 38.9% was exported. The massive export of cobalt commodities resulted in China bearing a disproportionate responsibility for carbon emission reduction. The research results can provide a scientific reference for the reasonable adjustment of the trade structure of cobalt commodities and realization of the economic and efficient utilization of cobalt resources in China.

Influence of Cell Opening Methods on Electrolyte Removal during Processing in Lithium-Ion Battery Recycling

Lithium-ion batteries (LIBs) are an important pillar for the sustainable transition of the mobility and energy storage sector. LIBs are complex devices for which waste management must incorporate different recycling technologies to produce high-quality secondary (raw) materials at high recycling efficiencies (RE). This contribution to LIB recycling investigated the influence of different pretreatment strategies on the subsequent processing. The experimental study combined different dismantling depths and depollution temperatures with subsequent crushing and thermal drying. Therein, the removal of organic solvent is quantified during liberation and separation. This allows to evaluate the safety of cell opening according to the initial depollution status. These process steps play a key role in the recycling of LIBs when using the low-temperature route. Therefore, combinations of pretreatment and processing steps regarding technical and economic feasibility are discussed. Moreover, the process medium and equipment properties for a safe cell opening, the technical recycling efficiencies and their consequences on future industrial LIB waste management are pointed out.

Improving Separation Efficiency in End-of-Life Lithium-Ion Batteries Flotation Using Attrition Pre-Treatment

The comminution of spent lithium-ion batteries (LIBs) produces a powder containing the active cell components, commonly referred to as “black mass.” Recently, froth flotation has been proposed to treat the fine fraction of black mass (<100 µm) as a method to separate anodic graphite particles from cathodic lithium metal oxides (LMOs). So far, pyrolysis has been considered as an effective treatment to remove organic binders in the black mass in preparation for flotation separation. In this work, the flotation performance of a pyrolyzed black mass obtained from an industrial recycling plant was improved by adding a pre-treatment step consisting of mechanical attrition with and without kerosene addition. The LMO recovery in the underflow product increased from 70% to 85% and the graphite recovery remained similar, around 86% recovery in the overflow product. To understand the flotation behavior, the spent black mass from pyrolyzed LIBs was compared to a model black mass, comprising fully liberated LMOs and graphite particles. In addition, ultrafine hydrophilic particles were added to the flotation feed as an entrainment tracer, showing that the LMO recovery in overflow products is a combination of entrainment and true flotation mechanisms. This study highlights that adding kerosene during attrition enhances the emulsification of kerosene, simultaneously increasing its (partial) spread on the LMOs, graphite, and residual binder, with a subsequent reduction in selectivity.