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Revolution within the revolution: solid state batteries promise to change the rules of the electric car, and silicon wants to be its star ingredient

Solid state batteries promise. They promise a lot. Up to 50% more autonomy, a longer useful life and up to six times faster charging, among other powerful improvements. Currently, some of the giants of the automotive industry are involved in its development, such as Volkswagen, BMW, Hyundai or Ford, among other companies, so this innovation can’t afford not to thrive. There is too much financial muscle pushing it.

In fact, the arrival of the first electric cars equipped with these batteries is very close. Ford and BMW expect Solid Power to deliver the first 100 Ah cells in the coming months, so both brands have confirmed that they are confident of launching their first vehicles equipped with this technology in 2022. Yes, surprisingly they should arrive next year.

Ford and BMW are confident of launching their first solid-state battery electric cars in 2022

Solid Power launched its solid state battery development project in 2012, but it is by no means the only company working on this battery technology. QuantumScape is receiving the financial backing of Volkswagen, Continental and Bill Gates, so there is no doubt that he is another of the actors that we are interested in not losing sight of in the coming months.

The increase in autonomy that I have talked about in the first paragraph of this article is the result of the increase in energy density, which in solid state batteries theoretically touches 500 Wh / kg. QuantumScape also ensures that in just 15 minutes it will be possible to bring a completely discharged battery to 80% of full charge. And, in addition to having a longer life due to the absence of degradation at the anode, these batteries promise to be more stable, safer and cheaper. Fingers crossed that these promises are kept.

The solid electrolyte and the silicon anode form a tandem with a future

In the report that I link here, we explain in some detail how solid-state batteries work, but to continue with this article, it is enough to remember that they use the same operating principle as lithium-ion batteries, but use a solid electrolyte instead of one in a liquid state. Each of the cells is made up of two metal or composite electrodes that are in contact with a conductive medium. The latter is the electrolyte.

This component usually uses a lithium salt that contains the ions that are necessary to propitiate reversible chemical reaction that takes place between the cathode and the anode, which are the electrodes. The companies that are developing solid state batteries have not disclosed the composition of their electrolyte because it is part of their intellectual property, but we know for sure that it does not use lithium salts in liquid state; uses a compound in solid state.

The interesting thing is that a few days ago a group of researchers from the University of California in San Diego (United States) published an article in Science in which they argued that by doping the graphite used in the manufacture of the anode with silicon, or even, manufacturing it completely with this last chemical element, it is possible multiply the amount of ions in the battery by ten. The authors of this article defend that this strategy allows to significantly increase the energy density of the battery, although they do not specify how much.

Solid state batteries with silicon anode promise to have an even higher energy density

According to them, introducing a silicon anode in a battery with lithium salts electrolyte is not a good idea because both elements interact causing the battery to degrade, become unstable and its capacity is reduced. However, in their article they reflect that none of this is a problem when using a solid electrolyte.

In addition, they ensure that their initial design is extremely stable, has a significantly longer useful life than lithium-ion batteries and guarantees at least 500 charge cycles. preserving 80% of capacity battery. It doesn’t sound bad at all. Fingers crossed that, as anticipated by BMW and Ford, the first solid-state battery electric cars will arrive next year. Although it does not yet incorporate a silicon anode.

Cover Image | Solid power

More information | Science