Li-Cycle uses Spoke & Hub Technologies based on the combination of mechanical safe size reduction and hydrometallurgical resource recovery to provide a customer-centric, end-of-life solution for lithium-ion battery recycling, while creating a secondary supply of critical battery materials.
Challenges
The rapid growth of electric vehicles has a significant impact on the demand for Li-ion batteries. By 2030, it is anticipated that 140 million electric vehicles will be on the roads worldwide, while 11 million metric tons of Li-ion batteries will reach the end of their service lives. Currently, most used Li-ion batteries are discharged in landfills, and less than 5% of batteries are recycled.
As shown in the figure below, a typical lithium-ion battery has four key components:
- Cathode: containing different formulations of lithium metal oxides and lithium iron phosphate depending on battery application and manufacturer, intercalated on a cathode backing foil/current collector (e.g. aluminum)—for example: LiNixMnyCozO2; LiCoO2 ; LiFePO4; LiMn2O4; LiNi0.8Co0.15Al0.05O2;
- Anode: generally containing graphite intercalated on an anode backing foil/current collector (such as copper);
- Electrolyte: for example, lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate monohydrate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(bistrifluoromethanesulphonyl) (LiTFSI), lithium organoborates, or lithium fluoroalkylphosphates dissolved in an organic solvent (e.g., mixtures of alkyl carbonates, e.g. C1-C6 alkyl carbonates such as ethylene carbonate (generally required as part of the mixture for sufficient negative electrode/anode passivation), ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, propylene carbonate); and
- Separator between the cathode and anode: for example, polymer or ceramic based.
Thus, materials found in lithium-ion batteries therefore include organics, iron, aluminum, copper, plastics, graphite, cobalt, nickel, manganese, and lithium. It is estimated that more than 11 million tonnes of spent battery packs contain approximately US$65 billion of residual value in metals and other components.
In addition, recycling lithium-ion batteries could reduce greenhouse gas emissions by approximately 1.2 billion equivalent tonnes of CO2 between 2017 and 2040 by offsetting/reducing the amount of raw material derived from primary sources (i.e. mining, refining) and preventing the landfilling of metals (e.g., heavy metals) and materials from spent lithium-ion batteries.
Thus, recovering materials from spent Li-ion batteries is highly desirable.
Pyrometallurgy is a fire process to recover valuable metals from waste lithium ion batteries. The pyrogenic process burns the organic binder in the electrode material by high-temperature incineration at near 1500 °C and then obtains the metal compound through flotation, precipitation and similar techniques.
However, the current pyrogenic recovery process burns the volatile organic compounds and generates a large quantity of acid corrosive gasses (such as HF and PF), which causes more severe secondary pollution and can cause great harm to human bodies and the environment. To treat harmful emissions, sophisticated equipment is needed, which raises the capex cost. Today, several large pyrometallurgy facilities recycle Li-ion batteries, recovering cobalt, nickel, and copper but not lithium, aluminum, or any organic compounds.
Hydrometallurgy processing or chemical leaching is a less energy-intensive and less capital-intensive alternative. These processes for extracting and separating cathode metals typically run below 100 °C and can recover lithium, copper, and other transition metals. The requirement for caustic reagents (such as hydrochloric, nitric, and sulfuric acids and hydrogen peroxide) is a drawback of traditional leaching techniques.
Li-Cycle’s solution
The Spoke-Hub technology
Li-Cycle developed Spoke-Hub recycling technologies for Li-ion batteries. The Spoke technology involves the mechanical reduction in size of incoming used batteries in a safe manner. Hub technology involves the hydrometallurgical recycling and resource recovery methods designed specifically for recycling lithium-ion batteries. Li-Cycle’s Spoke-Hub technology can recycle at least 95% of all materials found in used Li-ion batteries.
The Spoke: a safe size reduction technology
The Spoke facility is capable of recycling both large format lithium-ion batteries (e.g. automotive, energy storage system battery packs) and small format lithium-ion batteries (e.g. from laptops, mobile phones, tablets, etc.). Batteries entering these facilities are first discharged to inert objects, and then undergo a mechanical safe size reduction process that renders them suitable for further processing. The Spoke technology comprises the subsequent procedures:
1. Process Li-ion battery
This step processes used lithium-ion batteries to form a size-reduced feed stream.
First, incoming batteries are discharged. Discharging lithium-ion batteries facilitates the control of energy released during the possibility of short-circuiting when the anode and cathode of the battery come into contact during battery disassembly or multi-stage crushing/shredding.
Discharged batteries are crushed/shredded by crushers under aqueous solution immersion. Immersion in aqueous solution has several benefits:
- The solution prevents sparking caused by crushing/shredding and absorbs it as heat.
- Restricting the accumulation of oxygen reduces the risk of ignition during crushing.
- The solution promotes entrainment of battery electrolyte (e.g., LiPF6 in organic solvent) as it is released during lithium-ion battery crushing, thereby facilitating an increase in overall lithium recovery.
The multi-stage shredding/crushing helps mechanically separate the batteries, reduces energy consumption downstream, and facilitates equipment sizing optimization. In addition, multi-stage size reduction reduces particle size distribution variability, which facilitates leaching of target metals/materials.
The multi-stage crushing includes first crushing large format lithium-ion batteries to reduce their size to ≤400 mm; and then crushing the size-reduced large format lithium-ion batteries and/or small format lithium-ion batteries to reduce their size to ≤100 mm to form a shredded/crushed slurry.
The crushed/shredded slurry is screened, where undersized solids that are ≤10 mm pass through a screen and oversized solids that are ≤100 mm to ≥10 mm are returned to shredding for further size reduction. Shredding reduces the oversized solids to mm to facilitate magnetic separation.
The ≤10 mm solids are separated from the liquid by means such as a settling tank. Following the settling tank, the solid slurry is transferred to a belt filter for additional solid-liquid separation. The solid-liquid separation filtrate is sent to an organic (i.e. alkyl carbonates) removal circuit or recycled back to the crushers/shredders for reuse as make-up water. A portion of the recycle stream (either from/to the crushers/shredders or the organic removal circuit) is bled to a downstream leach tank to facilitate an increase in overall materials recovery and for background impurity level control.
The shredded stream is then conveyed by a self-cleaning conveyor to a hopper for storage prior to magnetic separation. The solid-liquid separation filtrate from belt filtration and the settling tank can be returned to a filter or vacuum distillation circuit to remove any organics (i.e. alkyl carbonates).
The distribution of the combined size-reduced solids is roughly as follows: (i) A fraction of coarse solids (≥3 mm) comprising shredded steel and/or aluminum casing, any electrical components, plastic, copper cable, aluminum cathode foil, copper anode foil, and possibly paper; (ii) A fraction of fine solid (≤0.5 mm) including anode powder and cathode powder.
Undersize materials with a particle size of less than about 5 mm, or less than about 1-2 mm, can be collected during the feed size reduction and diverted to downstream process steps. The undersize materials can be combined with a black mass solid stream, which can then be leached (described in further detail below).
2. Mag/Non-mag separating
In this step, the size-reduced feed stream is separated into a magnetic product stream and a non-magnetic feed stream.
The screened crushed/shredded slurry is sent to a magnetic separator for magnetic separation. Through wet/dry magnetic separation, magnetic materials (such as steel sheet; ferrous) are separated from non-magnetic/non-ferrous materials.
3. Isolating mag product:
In this step, a ferrous product is separated from the magnetic product stream.
The magnetic (mag) stream separated from the magnetic separator undergoes solid-liquid separation by reporting to a dewatering screen, producing shredded steel or ferrous material. The separated aqueous solution is recycled back to the magnetic separator to be used as make-up solution, and a portion of the recycled stream is bled to a downstream leach tank. Bleeding/sending a portion of the recycled stream to the leach tank may facilitate impurity control in the magnetic separator and dewatering screen circuit.
4. Stripping non-mag product
In this step, the non-magnetic feed stream is stripped using a stripping solvent to create a stripped slurry feed.
The non-magnetic/non-ferrous stream from magnetic separation is sent to a series of mixing tanks where a stripping solvent is added to remove the bonded black mass/electrode powder material from the first non-magnetic stream. The addition of stripping solvent, such as N-Methyl-2-pyrrolidone, dissolves the binder material, such as polyvinylidene fluoride (PVDF), and causes the electrode powder material to coagulate into a black mass.
5. Separating stripped slurry
In this step, the stripped slurry stream is separated into an oversize solids portion and an undersize stripped slurry stream.
The stripped slurry stream undergoes solid-liquid separation by reporting to a wire mesh screen with 500 μm openings, producing an oversize solids portion of the stripped slurry stream (i.e. larger solids portion of the separation), consisting of aluminum, copper, and plastics, and an undersized stripped slurry stream (i.e. liquid portion of the separation) containing smaller suspended solids including black mass.
6. Separating oversize solids
In this step, the oversize solids portion of the stripped slurry stream is separated into a preliminary aluminum product stream, a preliminary copper product stream, and a plastic product stream.
The oversize solids portion of the stripped slurry stream then undergoes further separation using a densimetric separator unit. The densimetric separator unit separates the oversize solids portion into three streams: a preliminary aluminum product stream, a preliminary copper product stream, and a plastic product stream. The isolated streams are washed before passing through a dewatering screen, which collects separate and washed preliminary aluminum product, preliminary copper product, and plastic product streams.
7. Solid-liquid separation
In this step, the undersize stripped slurry stream is separated into a black mass solid stream and recovered stripping solvent by solid-liquid separation.
The undersized stripped slurry stream is sent to a filter press for solid-liquid separation, producing a liquid containing the solvent and a black mass solid stream. The separated solvent is collected into a tank and recycled back to the stripping tanks as make-up solvent.
The black mass solid stream comprises at least one of the following: electrodes (e.g. metal oxide and/or metal phosphate cathode powders, graphite anode), plastic, and some residual non-ferrous (e.g. shredded copper and/or aluminum) components. This stream is conveyed to a leach tank for leaching, along with undersize materials having a particle size of less than about 5 mm, or less than about 1-2 mm, from the feed size reduction phase as described previously.
The Hub: Recycling Li, Ni, Co, Mn
At the central hydrometallurgical recycling plant called Hub transforms black mass from cathode and anode materials into reusable battery-grade end-products.
8. Acid leaching black mass
In this step, the black mass solid stream is leached with an acid to form a pregnant leach solution (PLS) and residual solids.
The leaching process is carried out in a series of tanks, such as conical-bottomed tanks, with high shear agitation. A conical-bottomed tank facilitates the settling of coarser, higher-density solid fractions. Agitation assists in suspending high-value fine fractions and promotes leaching kinetics. Multiple tanks optimize the kinetics of leaching reactions and offer operational redundancy.
Sulfuric acid is used to leach target metals/materials in the influent slurries. Hydrogen peroxide and oxygen gas are added to reduce and oxidize nobler metals in order to increase extraction rates and increase extraction of copper, cobalt, etc. but decrease nickel extraction.
9. Separating leach solution
During this step, the pregnant leach solution is separated to produce a first product stream consisting of the residual solids and a second product stream consisting of the pregnant leach solution.
The leached slurry produced by the leaching step is subjected to a solid-liquid separation, such as filtration, to produce a first product stream containing residual solids after the leaching step and a second product stream consisting of the pregnant leach solution.
10. Isolating a graphite product
In this step, a graphite product is isolated from the first product stream.
Following the leaching step, the first product stream containing residual solids is mixed with water and the pH is adjusted to a range between 4 and 8. The solution from the mixing tank is sent to a flotation cell in order to selectively separate hydrophobic components (such as graphite, organics, and residual plastics) from hydrophilic components.
Flotation takes place over two stages to maximize separation and recovery: a rougher flotation followed by a cleaner flotation. Rougher flotation separates a maximum amount of hydrophobic components from water. The rougher froth is sent to a cleaning stage for further flotation. The rougher flotation residue/water is sent to a holding tank, where it is mixed with the cleaner flotation residue/water for downstream processing.
Cleaner flotation further isolates hydrophobic components from the hydrophilic process mixing water by separating the rougher froth. The isolated froth is subjected to solid-liquid separation by centrifugation to isolate the graphite product (e.g., graphite concentrate). Before being recycled back to the mixing tank, the filtrate from the solid-liquid separation is held in a holding tank.
The pregnant leach solution resulting from the solid-liquid separation is sent to a dual media filter. A first media layer removes entrained organics (i.e. ethylene carbonate/EC and/or ethyl methyl carbonate/EMC) from the pregnant leach solution, whereas a second media filter removes fine suspended solids.
The filtered pregnant leach solution is then sent to a holding tank before being processed through copper-ion exchange or solvent extraction. Recovered organics (i.e. alkyl carbonates) from dual media filtration are collected. A media backwash outlet stream (e.g., aqueous solution and any residual fine particulates, such as residual graphite, fine plastics entrained by the second media layer, and minimal entrained organics) is recycled to aqueous solution treatment facilities and reused as make-up water/aqueous solution.
A graphite product is isolated via solid-liquid separation. The graphite product is potentially mixed with some plastic and paper, and may be further purified by:
(i) low temperature chemical treatment, which involves multi-stage acid washing (e.g. using sulfuric or hydrochloric acid) to remove impurities/soluble metals (e.g. residual soluble metals such as lithium, nickel, cobalt, copper, and/or manganese) to produce a higher purity graphite concentrate; and/or
(ii) thermal purification, e.g., raising the temperature of the concentrate via pyrometallurgical methods (e.g. using a furnace to raise the graphite temperature to 1000 °C to 2000 °C.) to volatilize specific constituents (e.g., residual organic and plastics) to produce a higher purity graphite product.
11. Isolating Cu product:
In this step, a copper product is isolated from the second product stream to form a third product stream.
Dual-media filtered pregnant leach solution is sent to a copper-ion exchange for selective copper separation from the inlet stream. Copper electrowinning is used to deposit copper as a copper plate from the eluate/copper-rich liquor. A portion of the recycle stream is bled into the upstream leach tank.
Alternatively, copper is deposited via solvent extraction and electrowinning when the copper concentration in the pregnant leach solution is approximately 5 g/L. The extraction stages of copper solvent extraction consist of mixer-settlers, as so the wash stages and and stripping stages. As needed, make-up acid or base (e.g. sodium hydroxide) is added to the influent pregnant leach solution in order to appropriately adjust pH for optimal copper extraction. The extraction mixer-settler stage utilizes an organic extractant in a diluent to extract copper selectively into the organic phase:
Extraction: CuSO4(aq)+2HR(org)→CuR2(org)+H2SO4(aq)
The copper-loaded organic phase is then sent to the stripping stage, where the extracted copper ions are stripped back into the aqueous phase using spent electrolyte from copper electrowinning containing acid (e.g., sulfuric acid/H2SO4):
Stripping: CUR2(org)+H2SO4(aq)→CuSO4(aq)+2HR(org)
12. Isolating Al and/or Fe product
In this step, aluminum (Al) and/or iron (Fe) products are isolated from the third product stream to form a fourth product stream.
The copper isolation raffinate can then optionally be sparged with oxygen to oxidize any ferrous (Fe2+) content to insoluble ferric (Fe3+) and subsequently treated with a hydroxide (e.g., sodium hydroxide, hydrated lime/calcium hydroxide, etc.) to precipitate an Al and/or Fe hydroxide product. The Al/and or Fe product could then undergo solid-liquid separation, resulting in the collection of a solid filter cake.
13. Isolating Co, Ni, and/or Mn product
In this step, cobalt (Co), nickel (Ni), and/or manganese (Mn) products are isolated from the fourth product stream to form a fifth product stream.
The Al and/or Fe-depleted solution is then reacted with a hydroxide (e.g., sodium hydroxide, hydrated lime/calcium hydroxide, etc.) to precipitate a Co, Ni, and/or Mn hydroxide product; reacted with a carbonate (e.g., sodium carbonate) to precipitate a Co, Ni, and/or Mn carbonate product; and evaporatively crystallized to form a Co, Ni, and/or Mn sulfate product.
The Co, Ni, and/or Mn products are then subjected to solid-liquid separation, followed by the collection of a solid filter cake. The leachate is then subjected to an evaporative crystallizer, and the resulting product will consist of a mixture of cobalt sulfate heptahydrate (CoSO4.7H2O), nickel sulfate hexahydrate (NiSO4.6H2O), and manganese sulfate monohydrate (MnSO4.H2O). The crystallized slurry is then subjected to solid-liquid separation (e.g., centrifuge or filter press) and a drier to remove excess water.
14. Isolating a salt by-product
In this step, a salt by-product is isolated from the fifth product stream to form a sixth product stream.
Prior to lithium recovery, sodium sulfate is isolated as a salt by-product utilizing the Co, Ni, and/or Mn solid-liquid separation filtrate. Crystallization of the filtrate yields sodium sulfate decahydrate. This crystallization is accomplished by cooling the sodium sulfate solution in a crystallizer, such as draft tube baffle crystalliser, after which the crystals undergo solid-liquid separation via a centrifuge or filter press, and the isolated solid crystals are dried and cooled. Subsequently, the filtrate from the solid-liquid separation of the isolated crystals is sent to lithium recovery.
15. Isolating Li product
In this step, a lithium product is isolated from the sixth product stream.
The filtrate from the solid-liquid separation of sodium sulfate is then reacted with sodium carbonate to precipitate lithium carbonate (Li2CO3). This lithium carbonate product undergoes solid-liquid separation (e.g., centrifugation) and a solid cake is collected. To further purify the lithium carbonate, it is sent to an ion exchange column to remove trace impurities such as calcium and magnesium; and then to a bicarbonation circuit where carbon dioxide is bubbled into, for example, a dissolution/digestion tank to convert the lithium carbonate into more soluble lithium bicarbonate before being recrystallized into a higher purity lithium carbonate slurry. The slurry is then solid-liquid separated to produce lithium carbonate of high purity and is dried.
Sodium sulfate is isolated as a product. The centrate from the Li2CO3 solid/liquid separation is sent to an evaporative crystallizer to produce sodium sulfate decahydrate (Na2SO4.10H2O). During crystallization, sulfuric acid is added to convert any residual carbonate (e.g. Na2CO3(aq)) into a sulfate form. The resulting crystallized slurry is solid-liquid separated (e.g., centrifuged), and the solid product is sent to a drier (e.g., a flash drier). The drier removes moisture and generates anhydrous sodium sulfate.
Products
Li-Cycle currently operates two Spokes in Kingston, Ontario, and Rochester, New York, each with a recycling capacity of 5,000 mt (metric tons)/year. More Spokes will be built in Gilbert, Arizona, Tuscaloosa, and Alabama.
The Spokes at Arizona and Alabama will represent the next generation of spoke design innovation in terms of scale and process capability. These facilities are capable of processing complete battery packs for electric vehicles, making the process safer and more labor-efficient. Both facilities will be able to recycle 10,000 mt/year of used lithium batteries into black mass.
Li-Cycle plans to produce between 6,500 mt and 7,500 mt of black mass containing battery metals from its growing North America battery recycling operations in 2022.
Currently, Li-Cycle sells the majority of its black mass to third parties. When the Rochester black mass processing Hub facility comes online in 2023, however, it will direct an increasing amount of output to it. The Rochester Hub will be able to process 35,000 mt/year of black mass and produce nickel sulfate, cobalt sulfate and lithium carbonate.
Financials
Li-Cycle has raised a total of $667.7M in funding over 6 rounds. Their latest funding was raised on May 5, 2022 from a Post-IPO Debt round.
Li-Cycle is registered under the ticker NYSE:LICY.
Li-Cycle is funded by 9 investors, including Glencore, LG Chem, LG Energy Solution, Koch Strategic Platforms, Neuberger Berman Group, Moore Strategic Ventures, Carnelian Energy Capital Management, Franklin Templeton Investments, and Sustainable Development Technology Canada. Glencore and LG Chem are the most recent investors.
Employees
Ajay Kochhar is Co-Founder, President & CEO.
Tim Johnston is Co-Founder.
Board Member and Advisor
Tim Johnston and Kunal Sinha are board members.
