Cylib, a German clean tech company founded in 2022, has developed lithium battery recycling technology that uses water and supercritical CO₂ to recover lithium carbonate from black mass before it is acid leached or smelted. This early stage lithium recovery avoids costly lithium extraction from a pyrometallurgy treatment and hydrometallurgical purifying of slags. Cylib’s method is accompanied by a reduction in CO₂ emissions, and it has a recycling efficiency of over 90%.
Challenges: lithium battery recycling
Why recycle lithium battery
Li-ion batteries are in high demand because electric cars are becoming more and more popular. By 2030, 140 million electric vehicles are expected to be on the roads around the world, and 11 million metric tons of Li-ion batteries will have reached the end of their useful lives. At the moment, most used Li-ion batteries end up in landfills, and only about 5% are recycled.
A typical lithium-ion battery has four key components:
(i) Cathode: containing different formulations of lithium metal oxides and lithium iron phosphate intercalated on a cathode backing foil/current collector (e.g. aluminum)—for example: LiNiₓMnₘCOₙO₂, LiCoO₂, LiFePO₄, LiMn₂O₄, and LiN₀.₈Co₀.₁₅Al₀.₀₅O₂;
(ii) Anode: generally containing graphite intercalated on an anode backing foil/current collector (such as copper);
(iii) Electrolyte: lithium salts such as lithium hexafluorophosphate (LiPF₆), lithium tetrafluoroborate (LiBF₄), and lithium perchlorate (LiClO₄) are dissolved in an organic solvent (e.g., ethylene carbonate, dimethyl carbonate, diethyl carbonate, propylene carbonate); and
So, iron, aluminum, copper, plastics, graphite, cobalt, nickel, manganese, and lithium are all parts of lithium-ion batteries. It is estimated that more than 11 million tons of spent battery packs contain approximately US$65 billion of residual value in metals and other components.
Also, recycling lithium-ion batteries could cut greenhouse gas emissions by about 1.2 billion equivalent tons of CO₂ between 2017 and 2040. This could be done by offsetting or reducing the amount of raw material from primary sources (like mining and refining) and keeping metals (like heavy metals) and other materials from used lithium-ion batteries from going to landfills.
Thus, recovering materials from spent lithium batteries is highly desirable.
How to recycle lithium battery
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 nearly 1,500 ºC and then obtains the metal compound through flotation, precipitation, and other techniques. 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 ºC and can recover lithium, copper, and other transition metals. Traditional leaching methods have a drawback in that they need caustic reagents like hydrochloric, nitric, and sulfuric acids and hydrogen peroxide. It also requires sodium carbonate (Na₂CO₃) to extract lithium.
In contrast to conventional lithium battery recycling technologies, Cylib uses water and supercritical CO₂ to recycle lithium from black mass before it is leached or smelted.
The spent lithium batteries are subjected to burning, shredding, sieving, and sorting in order to obtain lithium enriched black mass and metals such as aluminum, copper, and steel. Lithium is extracted from black mass by using water and supercritical CO₂ at a high temperature and pressure. Through evaporation, lithium carbonate is obtained from aqueous solution. Lithium depleted black mass is smelted or acid leached to extract electrode metals like nickel and cobalt. This early stage lithium recovery (ESLR) method prevents lithium distribution, the further use of additives required for hydrometallurgical treatments, and costly slag refining.
Cylib battery recycling
The diagram below depicts the process of recycling lithium batteries.
- Thermal pretreatment
Spent lithium batteries are thermally treated at temperatures of 600 ºC in the absence of oxygen. This thermal pretreatment allows for the safe deactivation of the batteries and facilitates downstream recycling without the risk of a so-called thermal runaway. Thus, this procedure prevents subsequent shredding from igniting. In addition, the thermal pretreatment improves the detaching of black mass from the current collector foils of the cell.
The thermally treated cells are then shredded and sieved to extract the black mass.
- Shredding, sieving, and sorting
Batteries that have been thermally treated are shredded into small particles. This is advantageous for the efficiency of subsequent sieving, sorting, and hydrometallurgical treatments.
The black mass can be separated from aluminum and copper foils and steel casings by means of sieving and sorting. The lithium-enriched black mass includes all electrochemically active electrode components, including Co, Ni, Mn, and C. The black mass’s particle size is approximately 100 microns.
- Early-stage Li-recovery
This black mass is then leached in water (H₂O) and supercritical CO₂ at a high temperature and high pressure. In water, carbonic acid (H₂CO₃) is produced via the following chemical reactions:
CO₂ + H₂O ⇆ H₂CO₃
H₂CO₃ ⇆ H⁺ + HCO₃⁻
HCO₃⁻ ⇆ H⁺ + CO₃²⁻
As the pH of the solution decreases to 7–8, the lithium leaching efficiency increases.
Through a preliminary filtration, the lithium-enriched aqueous solution and the Li-depleted black mass are separated, producing a lithium-containing filtrate (solution) and a filter cake containing carbon, nickel, cobalt, manganese, aluminum, and copper fragments.
The lithium-containing solution is boiled to precipitate lithium carbonate (Li₂CO₃). This is due to the facts that the solubility of lithium carbonate in water is reduced from 13.3 g/liter at 20 ºC to 7.2 g/liter at 100 ºC and that the lithium carbonate has a lower solubility in water than lithium bicarbonate (LiHCO₃). Lithium carbonate precipitation induces the conversion of lithium bicarbonate to lithium carbonate.
2Li⁺ + CO₃²⁻ → Li₂CO₃↓
Therefore, the full boiling of the aqueous solution can produce pure lithium carbonate.
- Pyrometallurgy or Hydrometallurgy of Li-depleted black mass
The filter cake undergoes either pyrometallurgy or hydrometallurgy process to extract electrode metals such as nickel (Ni) and cobalt (Co).
The advantages of Cylib technology
Compared to other techniques, Cylib’s early-stage lithium recovery technology has several advantages:
- Avoiding the costly lithium extraction via pyrometallurgy treatment and hydrometallurgical purifying of slags;
- Avoiding lithium losses in various byproducts of chemical solution purification and metal extraction;
- Conventional lithium carbonation by Na₂CO₃ is avoided, and no further chemicals are required, making lithium recovery more environmentally friendly; and
- The subsequent hydrometallurgical treatment of the filter cake for electrode metal extraction requires fewer leaching agents and fewer pH-adjustment additives.
Lithium battery recycling market
In 2022, the lithium-ion battery recycling market was worth USD 6.5 billion. By 2031, it is expected to be worth USD 35.1 billion, thanks to a CAGR of 20.6% from 2022 to 2031. The market is growing because more money is being put into making electric cars, there are subsidies to encourage recycling batteries, the government is doing things that are good for the market, and there is more demand for clean power sources.
In 2023, the European Union implemented new policies on lithium battery recycling to promote sustainability, circular economy, and technological progress in the battery sector. The new European Battery Regulation covers the entire value chain, from technical documentation to environmental footprint declarations and recycling policies.
In the United States, lithium battery recycling policies vary by state. Some states have implemented their own recycling laws and regulations. For example, in California, a Senate bill would require battery suppliers to ensure that all “vehicle traction batteries” be recovered, reused, repurposed, or recycled.
Lithium battery recycling can be profitable. The financial viability of recycling electric vehicle lithium-ion batteries has been demonstrated, with cost/profit ranging from (-21.43 – +21.91) $·kWh⁻¹, depending on factors such as transportation and processing costs. By2025, the money made from one ton of recycled batteries could be close to $600.
Cylib is building a pilot factory in Aachen, Germany to demonstrate and commercialize its innovative lithium battery recycling technology. The pilot factory will recycle EV battery packs, modules, and cells, as well as micro-mobility batteries. The pilot line will be able to process one battery pack (300-500 kg) per day and will handle the whole end-of-end process.
Cylib is funded by 10 investors:
- Vsquared Ventures
- Karim Tabet Jalbout
- Kai Hansen
- 10x Founders
- World Fund
- Leopold König
- Lawrence Leuschner
- Torge Thönnessen
- Maximilian Odendahl
Lilian Schwich is CEO.