The Need of high-purity lithium hydroxide
The electrical vehicle (EV) market is undergoing a revolution transforming the transportation landscape using lithium-ion battery technology. The demand for electric vehicles is not just increasing; it's projected to skyrocket over five times the 2022 production values by 2031. To meet this challenge, high-purity lithium hydroxide and lithium carbonate are required as essential materials for the formulation of these batteries.
The primary sources of lithium are brine lakes (Salars) and mineral deposits, mainly Spodumene ore. The Spodumene ore contains up to 6 % lithium. Conventional mining operations extract minerals from the ground through either underground pit excavation or surface strip mining, depending on the location of the mineral lode.
Lithium Conversion
Producing high-quality lithium products for EV batteries is not without its challenges. In many cases, Lithium Carbonate may be produced that is a lower quality than needed for EV batteries. It may also be desirable to use high grade Lithium Hydroxide as part of the cathode materials instead of the carbonate form. However, plants that are designed to produce the lower quality Lithium Carbonate may be difficult to modify to produce a high-quality battery grade material or lack resources such as fresh water needed in the conversion. Despite these challenges, a number of plants currently produce the Lithium Carbonate and then ship this material to plants specially designed to convert the lower grade Lithium Carbonate to a high-quality battery grade Lithium Hydroxide with most of these currently found in China.
Process to Convert Lithium Carbonate to Lithium Hydroxide
The process to convert lithium carbonate to lithium hydroxide involves first dissolving lithium carbonate in water to form a lithium carbonate solution. This solution is then reacted with calcium hydroxide (slaked lime) to precipitate calcium carbonate and form lithium hydroxide in solution. Finally, the lithium hydroxide solution is filtered to remove the precipitated calcium carbonate and then concentrated and crystallized to produce battery-grade lithium hydroxide.
Process to Convert Lithium Carbonate to Lithium Hydroxide
| Filter | Filtration Value | Separation Product |
|---|---|---|
| 1 | Collect Technical Grade Lithium Hydroxide Product | Automated regenerative cartridge |
| 2 | Protect Ion-Exchange (IX) resin and crystallizer from carryover solids | 1 - 5 Micron Filter |
| 3 | Remove trace solids and Ion Exchange resin fines before crystallizer | 1 Micron Filter |
| 4 | Collect Battery Grade Lithium Hydroxide Product | Automated regenerative cartridge |
| 5 | Protect RO filtration unit from fouling | 10 Micron Filter |
| 6 | Removal of contaminant from raw water feed to RO & utility water for other uses including flushing out equipment | 10 - 20 Mircon Filter |
Material Purity Specifications
Lithium-ion batteries have strict purity requirements for the materials used in their manufacture. Impurities can lead to poor charging performance, including reduced vehicle range of operation, more frequent need to charge, problems with batteries starting at colder temperatures and, in some extreme cases, the batteries catching on fire. A significant issue with the current lithium conversion practice is the reliability of the operation in producing high-quality lithium products. Battery-grade purity specifications for Lithium Hydroxide and Lithium Carbonate are provided in Table 1. Improved filtration and separation can be essential in improving the process reliability for producing consistent high-purity products and improving product yields, reducing product re-work, and reducing operation costs.
| Battery Grade "LiOH-H₂O" (Lithium Hydroxide Monohydride) Purity Specs | ||
|---|---|---|
| LiOH, wt% | 56.5 | min |
| CO2, wt% | 0.35 | max |
| Cl, wt% | 0.0020 | max |
| SO4, wt% | 0.010 | max |
| Ca, wppm | 15 | max |
| Fe, wppm | 5 | max |
| Na, wppm | 20 | max |
| Al, wppm | 10 | max |
| Cr, wppm | 5 | max |
| Cu, wppm | 5 | max |
| K, wppm | 10 | max |
| Ni, wppm | 10 | max |
| Si, wppm | 30 | max |
| Zn, wppm | 10 | max |
| Heavy metals as Pb | 10 | max |
| Acid Insolubles, wt% | 0.010 | max |
EV Battery Value Chain
Effective filtration and separation are crucial at each stage of the electric vehicle (EV) battery value chain to ensure successful yield, purity, and reliability processes. For base materials, mining and unique material processing are required for Nickel, Cobalt and Aluminium and lithium. Active materials involve treating chemicals, specialty chemicals, and polymers to make the essential battery components: the separator, electrolyte, and anode/cathode. The battery cells also use chemicals and specialty chemicals that must be at rigorous purity levels to prepare the casing, filling operations, and slurries.
Pall Corporation is your filtration and separation needs partner and has experience throughout the EV battery value chain. Pall has over 400 qualified Engineers and Scientists who can provide prototype testing, on-site pilot testing, best practice training, process optimization, audits, contaminant analysis, application troubleshooting, validation services, presentations at scientific forums, and journal publications.
Applications in the EV Battery Value Chain
Base materials
| Active materials
| Battery cells
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Maximize your lithium production efficiency with our efficient filtration solutions. Contact our experts and let us help you take your process to the next level.