Metal process

Extraction of Li using a one-step process for cost reduction

Researchers published a study in the journal ACS Energy Letters discuss a new one-step electrochemical process for lithium extraction bypassing the separation/purification step which tends to increase the cost of production.

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Study: A raw material pathway for lithium: coupled electrochemical extraction and direct manufacturing of materials for batteries. Image credit: Olivier Le Moal/Shutterstock.com

The importance of lithium

Due to its many uses in multiple industries, especially due to the rapidly increasing consumption of Li-ion/Li batteries for consumer appliances, electric cars, and grid electricity retention, lithium is becoming quickly a crucial commodity. By 2030, demand for Li is expected to exceed 2 million metric tons.

Limitations of brine and ore extraction processes

Currently, salt lake solutions and ores are mined for Li, which is then separated from the ore and purified using chemicals. In practice, this strategy comes up against two major obstacles. First, global Li consumption often cannot be met due to the restricted and inconsistent global distribution of the deposit.

Second, the treatment processes for settling and refining are slow and inefficient (50% recovery), and they rely heavily on waste treatment and clean water, which is less than ideal. technically or financially.

What new methods are being researched?

Standard centrifugation techniques, which require pre-concentration of brine, deposition reagent, and post-Li separation, are time-consuming and expensive despite the technical skill of the manufacturing operation.

The low Li content and contamination by other ions prevented the direct separation of Li from catalytically complicated and low-Li fluids, which is preferred. Many innovative Li recovery techniques have been presented as a way to overcome the obstacles based on the principles of sorption, nano-purification, electrocoagulation and electrolysis.

New approaches to lithium extraction

With over 7% recovery after 72 hours, a unique electrodialysis method for Li extraction using a homogeneous lithium nanocomposite was demonstrated. Moreover, using a solid Li1+xAlthereGe2 yearsPO43 membrane, Zhou’s team created an electrochemical technique and verified the adsorption of Li metal from simulated seawater.

However, the compositional alteration and endurance of Li compounds in aqueous solutions are crucial for continuous Li processing techniques.

After Li extraction, many expensive processes of absorbent replacement and Li filtration are still required to produce industrial-scale usable supplies of Li. So this is a common challenge for the Li extraction process mentioned above.

The new technology differs in some aspects. A specific Li-ion barrier (Li1.5Al0.5Ge1.5(PO4)3LAGP) and inexpensive electrochemical manganese dioxide (EMD) are used as Li barrier and host, respectively, and it is based on a combination of electrolytic and electrochemical membrane intercalation processes.

Researchers focused on a material with exceptional Li separation performance and efficiency, limiting post-processing expenses rather than employing low-capacity compounds such as inherently reconfigurable FePO.4.

Advantages of modern technology

The three main advantages of the proposed technology are as follows. First, the extracted Li is exceptionally pure. The second and most important is the end of expensive Li separation and purification. High efficiency and cheap cost is the third major advantage it provides.

Depending on the desired cathode formulation, Host Li and Collected EMD (Li-EMD) are preliminary components for rechargeable cell cathodes that can be effectively used for cathode synthesis with the inclusion of essential ingredients .

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Determined by the measured Li removal capacity and the anticipated EMD potential, the total Li intercalation volume was 220 mAh g-1, a recovery efficiency of 71.4%. If all Mn ions are considered to have a 4+ valence, the reported harvesting capacity suggests that 0.772 mol of Li can be extracted per 1 mol of EMD, which is consistent with chemical analysis.

Using the Li recovered using the EMD/LAGP process, a techno-economic analysis (TEA) was performed to calculate the production cost of the Li battery cathodes. Compared to the $18.9 kg-1 of the LiMn2O4-R2 route, the MBSP of the LiMn2O4-R1 route is considerably lower at $12.8 kg-1.

The overall results showed that the cost of LiMn2O4 and NMC333 spinel produced using this technique is cheaper than other Li separation techniques, and even on par with consumer applications.

In short, this Li recovery method can overcome the problems of Li scarcity and cell cost, enabling vehicle electrification and reducing socio-economic system emissions.

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Reference

Lu, D. and. al. (2022) A lithium feedstock pathway: coupled electrochemical extraction and direct fabrication of battery materials. ACS Energy Letters, Volume 7. 2420 – 2427. Available at: https://doi.org/10.1021/acsenergylett.2c01216
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