Our lithium batteries hardly use cobalt, says Musk

Tesla CEO Ailong·masike said in a conference call that the company had mastered the technology to reduce cobalt use in lithium-ion batteries. The exact words were: Wethinkwecangetcobaltoalmostnothing. Tesla is currently mass-producing the Model 3 model, which is powered by lithium-ion batteries.

What message does Musk's statement convey?

At present, cobalt is an important metal for the production of lithium-ion batteries. It is mainly used as a positive material for batteries, such as lithium cobalt phosphate and lithium nickel cobalt manganese acid(NCM). By 2020, 75 % of lithium batteries will use cobalt because it has the effect of increasing the life of electric vehicles, estimates eCobalt Solutions, a maker of cobalt salts for batteries. However, about half of the world's cobalt comes from war-torn Zaire(Republic of the Congo). Many people are worried about the stability of the supply of cobalt. Coupled with the vigorous development of pure electric vehicles in various countries, the demand for cobalt has soared and the price of cobalt has doubled. Therefore, it is very practical to reduce the amount of cobalt in lithium-ion batteries.

So how to reduce the amount of cobalt?

The general technical solution is to increase the use of nickel, and the main role of nickel is also to increase the energy density of the battery. This research direction is called high nickel ternary material(such as 622/811, etc., these three figures represent the ratio of nickel cobalt manganese). However, the increase in the amount of nickel will lead to a reduction in the structural stability of the corresponding electrode material, which will lead to a significant reduction in the battery cycle life and safety. In addition, different material systems need to match electrolytes with different formulations. Because there are many impurities on the high-nickel ternary surface, the more optimized electrolytic formula is needed, and this is also a difficult point in research and development.

From Musk's point of view, Tesla's future lithium-ion battery program should be high nickel ternary. It is reported that the company that provided Tesla with lithium-ion batteries is the Matsushita Corporation of Japan. It is one of the several companies in the world that has mastered high-nickel ternary production technology. It uses lithium nickel cobalt aluminate(NCA) with a ratio of 8:1.5:0.5. Tesla had previously disclosed to shareholders that its lithium-ion batteries had the highest energy density in the industry and solved the problem of thermal stability after high nickel.

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