Several raw materials are essential for the production of lithium-ion batteries. These materials can be categorized into two groups based on their availability - critical and abundant. As part of our "Skill & Scale up" information campaign, we have studied the critical raw materials closely. This blog post, on the other hand, sheds light on the abundant raw materials such as aluminum, iron, phosphate, copper, and sodium.
Aluminum is the third most abundant element and the most common metal found in the earth's continental crust. Due to its lightness and versatility, it is used in a wide range of applications. It can be used as an element, in alloys, or in salts. In battery cells, aluminum serves as a conductor of electricity and housing material, especially in prismatic cells, fulfilling multiple functions at once.
Although aluminum is found in a wide variety of minerals, bauxite is used for industrial production. Hundreds of millions of tons of the ore are mined worldwide every year. Despite its abundance, bauxite is classified as a critical raw material. This is due to its economic importance and the risk of supply bottlenecks.
In the production of aluminum, a multi-stage process is used to separate the ferrous part of the ore and other impurities. This process involves the use of a high level of chemicals and energy. The resulting material is aluminum oxide, which can then be processed into metal using fused-salt electrolysis - a process that involves reducing the material with electricity. However, the production process generates a significant amount of waste due to the use of chemicals, and the high-temperature processes and electrolysis require large amounts of energy. Nevertheless, aluminum has high recycling rates and can be reused with significantly less energy, though this process generates salt slag as a waste product.
Iron is the second most common metal in the earth's continental crust after aluminum and is used in batteries in particular as a component of the LFP cathode material. LFP stands for lithium iron phosphate. Iron ore is available worldwide in the form of various minerals and is therefore not a critical raw material for batteries. Mainly extracted in open-cast mines and then crushed, iron ore must be chemically reduced in energy-intensive processes to produce iron. It is then mainly used in the steel industry. The synthesis of iron phosphate and LFP, the downstream product for battery cells, also requires the use of additional chemicals.
Iron is the most commonly used metal in the world owing to its abundance, unique properties, and low cost. Although it is used in a vast array of applications and products, its utilization as a raw material for batteries is negligible.
Phosphorus is used in battery cells with LFP cathodes. Here it is not used in elemental form, but as phosphate, more precisely as lithium iron phosphate. Apatite, a major phosphate, is considered the primary ore source for phosphorus production and is classified as a critical raw material by the EU due to its strategic importance. The largest deposits of phosphate minerals are located in North Africa (Morocco, Western Sahara), China and the USA.
Phosphorus can be extracted by heating in so-called electric arc furnaces or from sewage sludge. Similar to the extraction of metals from ores, phosphate extraction also requires the separation of unwanted components and purification. Compared to metal extraction from ores, this is associated with a moderate use of chemicals and energy. Cadmium or radioactive metals are particularly problematic. The extraction of phosphate from sewage sludge as an alternative to ores is also possible but is not nearly as economically relevant.
The use of phosphate in LFP cathodes is not of great importance as it is mainly used as a fertilizer. It can also be found in detergents or food products, where it is known as phosphoric acid and is used as an acidifier in cola drinks. Phosphate is not harmful to humans, as our tooth enamel consists mainly of it and our metabolism uses it as an energy source. However, over-fertilization with phosphate can lead to environmental damage.
Copper has been used for thousands of years and is named after the Copper Age, a period during the Stone Age when it was first mined as an element (5500-2900 BC). Copper is the only colored metal, besides gold, and is used in millions of tons annually due to its versatile properties as a conductor of electricity and heat. Only iron and aluminum are mined in larger quantities globally. Since 2023, the EU has classified copper as a critical raw material.
Its extraction from ores, in which copper often occurs together with other transition metals such as iron or cobalt, requires considerable energy and chemicals. In addition, large quantities of CO2 and sulfur dioxide (SO2) are produced from the sulfide ores during copper production, which are harmful to the environment and humans and therefore have to be separated at great expense. Once available as pure copper, however, the metal can be completely recycled. Despite this recycling option, a complete circular economy is currently not foreseeable due to the growing demand, particularly as a result of applications in the context of the energy transition: Demand cannot be met by recycled copper alone. In battery cells, copper is often used as a current conductor on the cathode side because, unlike aluminum, it does not react with the anode materials.
The development of sodium-ion batteries (SIBs) as a promising alternative to the widely used lithium-ion batteries (LIBs) is bringing the raw material sodium increasingly into the focus of battery cell production. In contrast to lithium, sodium is not used as a metal, but as an ion, and is available in its natural form. With almost inexhaustible deposits in the earth's continental crust and in seawater, the use of sodium instead of lithium enables a secure supply of raw materials. However, chemical substitution under otherwise identical cell chemistries is currently a challenge, which is why SIBs are still under development, while the market is dominated by LIBs.
Despite this challenge, sodium-ion batteries offer some promising advantages. Due to the natural occurrence of sodium ions in various minerals such as sodium chloride, sodium carbonate or sodium nitrate, the extraction of raw materials is comparatively simple and less problematic. These minerals can be extracted either by mining or from seawater, mainly in the form of NaCl. Sodium chloride in particular is an important source of raw materials and is either used directly or converted into other sodium compounds. The metallic portion of sodium, which is extracted using fused-salt electrolysis, only accounts for a small proportion.
Contrary to their promising properties, SIBs have a lower energy density and a higher weight per kilowatt hour than LIBs, which makes their use in electric vehicles more difficult. Nevertheless, the easy, inexpensive, and global availability of sodium chloride, which is also non-toxic, could make it a promising candidate to supplement or even replace lithium ions in battery cells. Further research and development in the field of sodium ion technology will be crucial to strengthen its competitiveness in the market.
Fraunhofer Research Institution for Battery Cell Production FFB