Lithium News

As lithium-ion batteries continue to decrease in price, they are quickly replacing the lead-acid batteries traditionally used in cars and other vehicles. This is creating a sudden abundance of used lead-acid batteries, which would be harmful to the environment and people if not recycled properly. To help deal with this problem, researchers developed an environmentally friendly method to turn lead from used lead-acid batteries into photodetectors operating in the UV-visible band.

“We believe this recycling strategy could significantly reduce the lead pollution resulting from waste lead-acid batteries, which is important to the environment,” said research team leader Longxing Su from Southern University of Science and Technology in China. “The photodetectors promote the recycling economy by creating a market for recycled lead. They can be used for a variety of applications including optical communication, chemical analysis and imaging.”

In the journal Optics Letters, Su and colleagues describe their process for extracting lead from discarded lead-acid batteries and then using it to synthesize lead(II)iodide (PbI₂) microcrystals suitable for use in photodetectors.

“The recycled PbI₂ microcrystals exhibit the quality and purity levels necessary for making photodetectors,” said Su. “We also show that the microcrystals can be used to make photodetectors with excellent stability, repeatability and fast response speeds.”

A new use for old batteries

Although the lead found in used lead-acid batteries can be recycled, most methods used for this are expensive and have various drawbacks. Su’s research team developed a more efficient strategy to produce PbI₂ from the lead paste found within lead-acid batteries.

To extract the lead from the paste, the researchers developed a one-pot process that requires only inexpensive, easily obtained chemicals and no commercial precursors, which would increase cost. The process involves placing the paste into a mixed solution with excess citric acid monohydrate, sodium citrate dihydrate and H₂O₂. The excess sodium citrate dihydrate causes almost all the generated lead citrate to dissolve in the mixed solution. The mixture is then filtered to obtain a clear solution containing lead. When excess hydroiodic acid is added to the solution, it forms yellow PbI₂ precipitate, which is collected and dried in a vacuum.

The researchers then used a simple spin-coating process to create a photodetector using the PbI₂ produced through this process. They investigated the photo response of the photodetector using a 300 W Xe-lamp as a UV-Visible light source and a semiconductor parameter instrument as an electric signal collector. The PbI₂ photodetector they fabricated showed a low dark current of 1.06 nA and an on-off ratio of 103 under 10 V bias voltage.

Next steps

The researchers are now working on scaling up their process to mass-produce recycled PbI₂. Before commercialization, the recycled PbI₂ and photodetectors made from it would need to be verified by independent testing organizations and companies interested in incorporating the photodetectors into downstream products.

“We hope that our work will be noticed by chemical companies and downstream firms so that our method can be extended into the market,” said Su. “Our green reactant recycling method may also be useful for other applications, such as making solar cells.”

Mohammad Asadi, assistant professor of chemical engineering at Illinois Institute of Technology, has published a paper in the journal Science describing the chemistry behind his novel lithium-air battery design. The insights will allow him to further optimize the battery design, with the potential for reaching ultra-high power densities far beyond current lithium-ion technology.

The battery design has the potential to store one kilowatt-hour per kilogram or higher—four times greater than lithium-ion battery technology, which would be transformative for electrifying transportation, especially heavy-duty vehicles such as airplanes, trains, and submarines.

Asadi aimed to make a battery with a solid electrolyte, which provides safety and energy benefits compared to liquid electrolyte batteries, and sought an option that would be compatible with the cathode and anode technologies that he has been developing for use in lithium-air batteries.

He chose a mix of polymer and ceramic, which are the two most common solid electrolytes but both of which have downsides. By combining them, Asadi found that he could take advantage of ceramic’s high ionic conductivity and the high stability and high interfacial connection of the polymer.

The result allows for the critical reversible reaction that enables the battery to function—lithium-dioxide formation and decomposition—to occur at high rates at room temperature, the first demonstration of this in a lithium-air battery.

As described in the Science paper, Asadi has conducted a range of experiments that demonstrate the science behind how this reaction occurs.

“We found that that solid-state electrolyte contributes around 75 percent of the total energy density. That tells us there is a lot of room for improvement because we believe we can minimize that thickness without compromising performance, and that would allow us to achieve a very, very high energy density,” says Asadi.

These experiments were conducted in collaboration with University of Illinois Chicago and Argonne National Laboratory. Asadi says he plans to work with industry partners as he now moves toward optimizing the battery design and engineering it for manufacturing.

“The technology is a breakthrough, and it has opened up a big window of possibility for taking these technologies to the market,” says Asadi.

Engineers at Australia’s RMIT University are proposing the idea of incorporating a 2D material into lithium-ion batteries to extend their lifetime up to three times longer than today’s technology, that is, to about nine years.

In a paper published in the journal Nature Communications, the researchers explain that they are using MXene, a class of material that is similar to graphene but has high electrical conductivity.

The big challenge with using MXene is that it rusts easily, thereby inhibiting electrical conductivity and rendering it unusable. To overcome this issue, the RMIT group looked into sound waves and discovered that at a certain frequency, they remove rust from MXene, restoring it to close to its original state.

This innovation could one day help to revitalize MXene batteries every few years.

“Surface oxide, which is rust, is difficult to remove, especially on this material, which is much, much thinner than a human hair,” Hossein Alijani, co-lead author of the study, said in a media statement. “Current methods used to reduce oxidation rely on the chemical coating of the material, which limits the use of the MXene in its native form. In this work, we show that exposing an oxidized MXene film to high-frequency vibrations for just a minute removes the rust on the film. This simple procedure allows its electrical and electrochemical performance to be recovered.”

Alijani and his colleagues believe that their work to remove rust from Mxene opens the door for the nanomaterial to be used in a wide range of applications in energy storage, sensors, wireless transmission and environmental remediation.

The ability to quickly restore oxidized materials to an almost pristine state also represents a game-changer in terms of the circular economy.

“Materials used in electronics, including batteries, generally suffer deterioration after two or three years of use due to rust forming,” Amgad Rezk, senior author of the paper, said. “With our method, we can potentially extend the lifetime of battery components by up to three times.”

While the innovation is promising, the team needs to work with industry to integrate its acoustics device into existing manufacturing systems and processes. They are also exploring the use of their invention to remove oxide layers from other materials for applications in sensing and renewable energy.

Shares in European Metals Holdings (ASX, LON: EMH) jumped on Monday in both Sydney and London after it said its Cinovec lithium project had been classified as strategic for the Czech Republic’s Usti region.

The nomination means the project will be given priority for grant funding from the Just Transition Fund (JTF), which supports European Union regions relying on fossil fuels and high-emission industries in their green transition.

Applications for grants through the JTF opened on November 14, 2022 and will close on December 31, 2023.

The stock rose almost 18% on the news in Australia to close 9.7% higher at A$0.74. In London it climbed 17.3% to 44 pence, but dropped later in the day to 39 pence — still 4% higher than Friday’s close.

The company said it is confident it will receive a significant portion of the funds applied for ahead of many other projects that have been submitted. The maximum amount the JTF could allocate to European Metals’ Cinovec project is 1.2 billion Czech koruna ($54.8 million), it said.

The designation provides “further evidence of strong support from the Czech government and the European Union and the Europe-wide recognition of the critical part which the Cinovec project will play in enabling the EU to reach its stated goals of lithium self-sufficiency by 2030,” chairperson Keith Coughlan said in the statement.

The funding could accelerate the project’s development and reduce the time until the first ore is produced, Coughlan noted.

European Metals controls the exploration licences to the Cinovec lithium/tin project in the Czech Republic, which it describes as Europe’s largest hard rock lithium deposit and the world’s fourth-largest non-brine deposit.

Czech utility CEZ, in which the state holds a 70% interest, has a 51% indirect stake in the project through European Metals’ 100%-owned local subsidiary Geomet.

The project sits some 100 kilometres northwest of Prague in the Czech Republic on the border with Germany. It lies on the Krusne hory/Erzgebirge metallogenic province at the northern border of the Bohemian Massif, one of the major metamorphic crystalline complexes of the European Variscan Belt.

Once in operations, the Cinovec mine will churn out 29,386 tonnes of lithium hydroxide a year over its 25-year productive life, according to a pre-feasibility study update, published in early January.