In recent years, scientific research has been exploring an alternative path to lithium batteries: lithium batteries rechargeable magnesium batteries. Magnesium is an element abundant on Earth, economical and above all stable. In theory, magnesium ions can transport two electrons instead of oneoffering a potentially higher energy capacity. On the other hand, however electrolytes suitable for magnesium are still difficult to develop and the technology is far from industrial production.
What are magnesium batteries and how do they work
Magnesium batteries are storage systems where the anode consists of metallic magnesiuman element much more abundant than lithium in the Earth’s crust and easily available. Their peculiarity is that they transport Mg²⁺ ions two electrons per atomtheoretically doubling the capacity compared to Li⁺ ions. According to research at the University of Waterloo, this characteristic makes magnesium an ideal candidate for high-energy-density, low-cost batteries.
The principle is similar to that of lithium batteries: during discharge, Mg²⁺ ions migrate from the anode to the cathode via an electrolyte, generating current. The difference is that magnesium, compared to lithium, does not form dendrites significantly, that is, tiny metal structures or sharp protuberances that can pierce the separator and cause fires and which continue to elongate cycle after cycle. This makes magnesium batteries intrinsically safer. The problem? Mg²⁺ ions are “slower” and difficult to move in traditional electrolytes. This is why many research groups are developing new organic and solid electrolytes to improve conductivity.
A recent prototype from Tohoku University demonstrated stable operation at room temperature, overcoming one of the technology’s historic limitations.
The possible uses of magnesium batteries
Magnesium batteries are still in the experimental phase, but could find applications in:
- stationary accumulation for renewable energy, thanks to the low cost of materials;
- electric vehiclesif energy density reaches competitive levels;
- consumer electronicsas a safer alternative to lithium cells.
European projects such as High Mag at the University of Limerick are aiming to develop magnesium batteries for sustainable mobility.
Differences compared to lithium batteries
Lithium batteries use lithium as the main material: it is very effective but relatively scarce and expensive. Magnesium batteries, on the other hand, are based on magnesium, a very strong element more abundant and economical. From a safety perspective, lithium batteries can develop dendrites, structures that increase the risk of short circuits and fires. Magnesium batteries do not have this problem significantly and are therefore more stable.
Regarding the state of the technology, lithium batteries are now mature and widely marketed, while magnesium batteries are still in the experimental phase And they are not available on the market. There energy density of lithium batteries is already very high. Magnesium batteries, in theory, could surpass it thanks to the double number of electrons transported by Mg²⁺ ions, but this potential has not yet been reached in current prototypes.
Finally, the electrolytes: for lithium there is a wide range of efficient and proven solutions. For magnesium, however, electrolytes are still the subject of research, because Mg²⁺ ions are more difficult to move inside the cell and electrolytes tend to form passivating layers that block charging.
Therefore, rechargeable magnesium batteries Not they are still widespread and today this technology remains laboratorywith promising prototypes but far from industrial production. However, advances in recent years indicate that the technology is accelerating.
