Most electric cars on the market use lithium ion batterieswhich offer high performance. To produce them, a huge quantity of raw materials is needed: a battery of this type on average contains well 185 kg of minerals and metals! Different types of materials are used depending on the battery component and therefore the function they have to perform. Many of these are critical raw materials: these are lithium, cobalt, manganese, nickel, aluminum, copper and phosphate. Let’s see what the components of lithium-ion batteries are and what raw materials they use.
The components of a lithium ion battery
Lithium-ion batteries alternate charge cycles (in which they receive energy from an external source) and download (when they release energy to power a device such as the engine of an electric car). They work thanks to a flow of electrons and ions (positively charged atoms that have given up an electron) of lithium that occurs between two electrodes. In a battery, different components are identified, each with its own function and made up of specific materials.
Electrodes
They are the elements that store energy and constitute the heart of the battery. Thenegative electrode (anode) is made up of graphitewhile thepositive electrode (cathode) from aluminum, nickel, lithium, manganese, cobalt, iron (present in different percentages depending on the type of battery).
Separator
It is a thin layer that separates the two electrodes from each other, consisting of a porous polymer which allows the flow of ions while avoiding contact between the anode and cathode, which would lead to a short circuit.
Electrolyte
It is a liquid substance or gel in which the electrodes are immersed, which allows the flow of ions between them. It consists of a lithium salt dissolved in a solvent.
Current collectors
They are metal sheets of aluminum or copperwhich collect the electric current produced by the electrodes.
Outer casing
Is it made of plastic or steel And aluminum and has the task of protecting the battery from impacts, making it waterproof and preventing the leakage of toxic substances.
The mineral composition of the battery
A lithium-ion battery with a capacity of 60 kWh contains well 185 kg of minerals and metals. For the most part it is about graphite (The 28.1%), which constitutes the anode. This is followed by thealuminum (18.9%), which is used in the cathode, in the current collectors and in the external casing. We then find the 15.7% nickelused in the cathode, the 10.8% of copperof which the current collectors are made, and another 10.8% of steelused for the outer casing. In addition to nickel, the cathode contains minor amounts of manganese, cobalt, lithium And iron.
These percentages vary depending on the type of battery, which is classified according to the composition of the cathode: in those NMC the cathode is made of lithium, nickel, manganese and cobalt; in those NCA from lithium, nickel, cobalt and aluminum oxide; in those LFP from lithium, iron and phosphate. The cathode It is the battery element for which the greater quantity of minerals and metalsand therefore the most expensive. It is also the most importantbecause its composition is crucial to the battery’s performance.
Let’s see the characteristics of the main raw materials that make up batteries NMC, the most common in the electric car sector.
Graphite (C)
It is a mineral consisting of carbonpresent in metamorphic rocks, which is formed following the carbonization process of organic matter. In nature it is quite abundant, but most lithium-ion batteries use synthetic graphiteproduced by processing hydrocarbons. Graphite is very light and has excellent electrical conductivity, which makes it ideal for making the anode. In addition, its cost is relatively low.
Lithium (Li)
It is a metal that is quite abundant in nature and is found in underground salt water and minerals such as carbonates, hydroxides and silicatessuch as spodumene or petalite. Its processing yields lithium carbonate and lithium hydroxide, which are used to produce battery cathodes. Lithium was chosen for this purpose because of its lightness and the ease with which it gives up an electron, transforming into a positive ion.
Cobalt (Co)
It is a very common metal in nature (in minerals including cobaltite and the heterogeneity) but in concentrations very low: for this reason cobalt is obtained as a by-product of the extraction and refining of metals such as copper and nickel. Cobalt oxide or cobalt sulfate can be used in batteries. In the cathode, cobalt acts as a stabilizer, making the battery safer.
Manganese (Mn)
It is one of the most abundant metals in the Earth’s crust, present in minerals such as pyrolusite and the manganite. In batteries it is used in the form of manganese dioxide not of natural origin, but of synthesis. In batteries, manganese increases the stability and the capacity to store energy.
Nickel (Ni)
It is mostly obtained from lateritessedimentary rocks whose main minerals are limonite and garnierite. It is also partly extracted from sulphides of magmatic origin. The presence of nickel in the cathode allows for more energy to be stored in a smaller space and for shorter recharging times.
For further information, here is a video on lithium extraction:
