For the expansion of the electric vehicle market, there is no doubt that long-lasting, fast-charging batteries are simply essential. However, lithium-ion batteries in use today continue to have some very significant negative characteristics: they take too long to charge, they are very heavy, and they are also too expensive.
For many years, researchers around the world have been working hard to harness the potential of solid-state lithium metal batteries , capable of retaining a greater amount of energy in the same volume. And, in addition, they charge in a fraction of the time if we compare them with traditional lithium-ion batteries.
Now, researchers from the Harvard School of Engineering and Applied Sciences (SEAS) are pursuing the goal of developing a useful lithium metal battery not only because of its high capacity, but also because of its energy density, which is characterized by being very stable (a very common problem that scientists have been facing for years.
Scientists have designed a stable lithium metal solid-state battery capable of being charged and discharged at least 10,000 times at high current density – far more cycles than previously demonstrated. In turn, the researchers paired the new design with a commercial, high-energy-density cathode material.
In the research, published in Nature , the scientists show that the solid-state battery could be different from the commercial liquid electrolyte lithium-ion battery, by unlocking far superior performance and, in addition, “being able to take advantage of its abundant opportunities” .
There is no doubt that one of the great challenges of this type of battery has been chemistry, since lithium batteries move ions from the cathode to the anode during charging. When the anode is made of lithium metal, different structures (dendrites) form on the surface that grow as roots, piercing the barrier that separates the anode from the cathode, increasing the risk of a short circuit or fire.
In order to overcome this challenge, the experts designed a multilayer battery capable of matching different materials, of different stabilities, between the anode and the cathode, thereby avoiding the introduction of lithium dendrites by controlling and containing them.
In this design, the first electrolyte would be more stable with lithium, but more prone to dendrite penetration. However, the second electrolyte would be less stable with lithium but more immune to dendrites. In this way, the dendrites grow through the graphite and the first electrolyte, but stop just as they reach the second. This barrier would prevent dendrites from passing through the layer and causing a dangerous short circuit in the battery.
And what is even more interesting: this technology could help increase the useful life of electric vehicles , making it similar to that of gasoline cars, by being able to extend it between 10 to 15 years, without having to replace the battery .
What’s more, thanks to its high current density, the battery could even pave the way for the arrival of electric vehicles capable of being fully charged in just 10 to 12 minutes .
Reference: A dynamic stability design strategy for lithium metal solid state batteries, Nature (2021). DOI: 10.1038 / s41586-021-03486-3
