Lithium batteries are still improving, but in the lower classes, where it is mainly about price and not so much about density, they are now slowly being replaced by Na-Ion sodium batteries. But sodium is not the only element grinding its teeth on lithium, and it could be another magnesium. Scientists from University of Hong Kong (HKU) recently presented the results of their research, when compared to previous results they moved significantly further. Their original accumulators Mg-Ion with an aqueous solution of salts (MgCl2 – WIS) reached an energy density of only 53 Wh/kg, the current ones are significantly better. Their new type already has a quasi-solid-state polymer electrolyte (MgCl2 – PEO) and brings several interesting properties.
First of all, it is quite high energy density 264 Wh/kg, which can be boldly equal to above-average lithium cells (not the best, but definitely above average and can boldly compete with e.g. Li-Ion NMC or Li-Ion NCA). The advantage of magnesium is also its low price and easy availability, the result should also be safe (the new electrolyte for magnesium batteries did not catch fire during the flame tests, but rather extinguished the fire). However, the problem with magnesium is the high tendency to passivate the surface, so non-aqueous salt solutions or organic solvents are usually tried, but they do not conduct ions well. Aqueous solutions, in turn, limit the possibilities to play with the voltage and lead to low energy densities. Here we have the aforementioned polymer electrolyte.
The new type of accumulators also shows a decent lifetime, reaching 88% of the original capacity after 900 cycles. The capacity and slightly the maximum voltage of the accumulator gradually decreases. If we are to translate this lifespan into electromobility, let’s consider an electric car with a realistic range of 400 km. After 900 cycles, it would have a range of 352 km, which means that it would reach this 88% after driving roughly 340,000 km. And even after such a portion of kilometers, we are still talking about a not too shortened range compared to the original one. The high service life even in the cold is interesting, at -22 °C the battery even had 90% after 900 cycles. But his problem is high temperatures, which he really doesn’t like. This is because degradation occurs a little faster there.
It should be noted here that this is a scientific article from a university, so something that is at the very beginning of development, so nothing that we should expect on the market anytime soon.
2023-11-10 18:00:15
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