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  Chemistry - Cobalt

Again and again, owners of purely electric cars are accused that their cars are not so environmentally friendly. Well, the arguments that relate to the current electricity mix can be refuted with the vision of 100 percent renewable energy. But what about the obvious problems in the production of electric cars?

The engines are probably on the way to improvement, if we are allowed to use this term at all. But what about batteries? In addition to lithium, a substance is needed that has a big producer, the 'Democratic Republic' of Congo, with over 50 percent. That's twice as much as the second strongest one. That makes them dependent and should be avoided. Tesla is said to have saved considerably more than half of the metal cobalt with the third battery generation of the Model 3.

Together with its chemical abbreviation we are writing 'cobalt' instead of 'Kobalt'. The name is not coincidentally similar to that of a goblin in German, but derived from it, because this metal was previously thought to be silver when it was mined, but this did not have its properties. They simply couldn't use it and called it the product of 'goblins' because it looked like silver but wasn't. Instead, toxic arsenic fumes were released in an attempt to melt it.

The lack of benefit has changed, for example, with the use as a blue colorant for glass and ceramics. In 1780 it was recognized as a chemical element and since the beginning of the 20th century it has also been useful in other ways, e.g. as a component in particularly hard alloys, for naturopathy and for colour televisions, which have almost disappeared in the meantime. Nowadays, the field of application for 'batteries' is clearly the largest, with e-cars still accounting for a relatively small proportion. Cobalt is very similar in its properties to its two neighbours in the periodic table, iron and nickel, as magnetizable as iron, colored grey, with the density of copper.

Cobalt can even have a higher magnetic power of attraction than iron and is more difficult to oxidize. The accusations also do not want to be silenced because cobalt is so difficult to extract. It only occurs in the corresponding ores with proportions far below one percent. For a long time it was only an additional product to the extraction of copper and nickel. However, in view of the achievable prices, the former by-product has become a main one. And it must also be clear that the demand can increase significantly with the proportion of batteries in electric cars.

What is Cobalt used for? We concentrate on batteries. Almost all of them contain cobalt. The majority is divided into lithium and nickel with magnesium and cobalt or cobalt and aluminiumy. The latter are considered the more powerful and are used by Tesla, but are also not quite as safe as the others. In the current discussion, Tesla fans point out that this American company is forbidden to purchase raw materials such as cobalt from certain politically unstable countries, such as Congo in this example.

Large companies operate the mines there, but almost 20 percent are also won privately by families, some of whose children, a total of over 100,000 people, often illegally and with very accident-prone aids. Of course they cannot refine the extracted ores but sell them to intermediaries. It is therefore possible that the cobalt extracted in this way reaches the world market in an uncontrolled manner. VW refers to the Responsible Raw Mmaterial Initiative and its certification system for cobalt melts to verify the origin of the material for its batteries. The Group is also a member of the World Economic Forum's Global Battery Alliance, which aims to ensure social and environmental sustainability in the value chain of battery raw materials - not only through of Cobalt.

The discussion becomes bad when it comes to numbers. In the USA, for example, it is claimed that there are still 4.5 g of cobalt in Model 3 instead of 11 g in the first Model S. However, the respective battery capacity is not stated. A German Tesla fan says it's 2.8 percent. According to the manufacturer, the battery weight of the Audi e-tron is 700 kg. The Model 3 with the smallest battery would then weigh the equivalent of 400 kg. Of which 2.8 percent would be more than 11 kg. You see, even the Tesla fans don't agree with each other. According to the VW ID.3 battery, 'over 12 percent' of cobalt or 'four times more cobalt than in the Tesla' should be used. and again it is not said which ID.3 battery is meant. The corresponding youtuber should be more careful with the numbers.

Much more important, however, is the question of why cobalt is used on the cathode of a lithium-ion battery. To do this, one has to use Co-Ni-Mg, electrically neutral together with oxygen and lithium ions. and at the anode also uncharged graphite. When the battery is charged, electrons of the metal oxides leave this block via cable in the direction of the anode and leave behind a positive total of charge. The lithium ions then migrate through the separator directly to the graphite and accumulate there together with the incoming electrons. Cathode and anode are electrically balanced again.

When unloading, the process reverses. The initial situation is that lithium atoms on the anode side are in a crystalline graphite compound, without being exposed to it by any chemical reaction. When the battery is discharged, the respective electron escapes again from the outermost shell of the lithium atom. This becomes a positively charged particle, a lithium ion. The Lithium ions in the graphite crystal are attracted by the remaining Co-Ni-Mg compound with oxygen of the cathode, can pass through the separator again unhindered and find a place in the metal oxide. The potential-free catthode is formed again. At VW the metal part consists of nickel and manganese sulphate, but also here with cobalt sulphate. The purer their mixture and also the purer the anhydrous electrolytic transport medium between cathode and anode, the more durable and better functioning the battery.

The metal oxide is therefore by no means just the storage place for the lithium ions, but also plays a role with its electrons in the (discharge) charging process. And obviously the presence of Cobalt is important for the energy density of the cathode. It is obviously still irreplaceable for a high performance of the battery. The Senior Vice President at BASF, one of the largest manufacturer of cathode material, says that the 124,000 tons total per year on 30 million cars with 90 kWh battery can be increased to more than three times even with the largest possible savings.

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