Magnesium instead of lithium for affordable batteries?

The Tokyo University of Sciences is conducting research on magnesium as a promising candidate for next-generation batteries. For now, the performance and capacity of magnesium batteries need to be improved to replace lithium, but research continues.

The TUS research team focused on a new cathode material with a spinel structure. Following extensive characterization and electrochemical performance experiments, they found a specific composition that could open the door to high-performance magnesium rechargeable batteries.
The team believes they have found the right path to success, as reported and published in the Journal of Electroanalytical Chemistry.

Currently, lithium-ion batteries have remained unmatched in terms of overall performance for many applications, as evidenced by their widespread use in everything from portable electronics to cell phone base stations. However, they suffer from some major drawbacks that are hard to ignore.

For example, lithium is quite expensive and the fact that it is being mined at an extreme rate doesn't help. Furthermore, the energy density of lithium-ion batteries is not sufficient to guarantee the range of electric vehicles and heavy machinery. These concerns, combined with the fact that batteries are highly dangerous if punctured or at high temperatures, have prompted scientists to look for alternative technologies.

Among the various elements being tested as efficient energy carriers for rechargeable batteries, magnesium (Mg) is a promising candidate. In addition to its safety and abundance, Mg has the potential to make batteries with higher capacities. However, there are a few issues that need to be resolved first. These include the low voltage window that Mg ions offer and the cycling unreliability observed in Mg battery materials.

To address these issues, a research team led by Vice President and Professor Yasushi Idemoto of Tokyo University of Science, Japan, is researching new cathode materials for Mg batteries. In particular, he sought to improve the performance of cathode materials based on the MgV (V:vanadium) system.

The researchers focused on the Mg1,33V1,67O4 system, but replaced some of the vanadium with manganese (Mn), resulting in materials with the formula Mg1,33V1,67-xMnxO4, where x ranges from 0.1 to 0, 4. While this system offered a high theoretical capability, further details on the structure, cycling and performance of the cathode needed to be investigated to understand its practical utility. As a result, researchers characterized the synthesized cathode materials using a variety of standard techniques.

First, they investigated the composition, crystal structure, electron distribution and particle morphology of Mg1.33V1.67-xMnxO4 compounds using X-ray diffraction and absorption, and transmission electron microscopy. Analyzes showed that Mg1.33V1.67-xMnxO4 has a spinel structure with a remarkably uniform composition.

Next, the researchers conducted a series of electrochemical measurements to evaluate the battery performance of Mg1.33V1.67-xMnxO4, using different electrolytes and testing the resulting charge/discharge properties at various temperatures.
The team observed a high discharge capacity for these cathode materials – especially Mg1.33V1.57Mn0.1O4 – which however varied significantly depending on the number of cycles. To understand why, they analyzed the local structure near the vanadium atoms in the material.

Prof. Idemoto explained: “It appears that the particularly stable crystalline structure, together with a large amount of charge compensation by vanadium, leads to the superior charge-discharge properties we observed for Mg1.33V1.57Mn0. 1O4. Overall, our results indicate that Mg1.33V1.57Mn0.1O4 could be a good candidate cathode material for magnesium rechargeable batteries.”

Satisfied with the current results and confident in what is to come, Prof. Idemoto concluded: "Through future research and development, magnesium batteries could outperform lithium-ion batteries due to the former's higher energy density."

Indeed, replacement MGV systems could lead to the long-awaited next-generation batteries. Let's hope that the long-awaited alternative to lithium for our rechargeable battery needs will soon come to fruition.

As political pressure for the use of electric mobility increases, the demand for batteries is also set to increase. Lithium, whose price is already quite high and which is processed in countries not exactly friendly to the free world, needs strong competition.

Several chemicals are currently being researched. Before long one or more of them will offer capable and competent competition. How much lower the cost and performance are for consumers is yet to be seen. The cost reduction will have to be quite substantial, as the capital commitment for a competitive chemistry will be high.

For now, as Prof. Idemoto observed, there is still research to be done, but the road could be the right one to have batteries at a good price.

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The article Magnesium instead of lithium for affordable batteries? comes from Economic Scenarios .

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This is a machine translation of a post published on Scenari Economici at the URL https://scenarieconomici.it/il-magnesio-al-posto-del-litio-per-batterie-convenienti/ on Fri, 17 Mar 2023 12:19:57 +0000.