Nestor Pinacho
On April 20, 2022, the Legislative Power approved an amendment to the Mining Law to establish that lithium became, from that moment on, the heritage of the Nation. As a result, the Mexican state has exclusive rights for the extraction of this mineral in seven municipalities in Sonora: Bacadéhuachi, Arivechi, Divisaderos, Granados, Huásabas, Nácori Chico, and Sahuaripa
Given the opportunities this opens up, a team from the Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas (UPIITA) at the Instituto Politécnico Nacional (IPN) has been researching the potential of this mineral for energy production for several years.
Dr. Mario Fidel García Sánchez, coordinator of the Energy Engineering program at UPIITA and a member of the research group on Advanced Materials and Technologies for Energy and Environment, works on the creation and testing of various types of batteries that use lithium.
The UPIITA professor and researcher explained that a battery operates based on chemical potential, which is essentially a concentration difference in the material it is made of: "If, for example, you put a bit of perfume in one corner, after a while, the entire room will smell of that fragrance because nature causes everything to segregate from where there is higher concentration to where there is less. The idea is somewhat similar in a battery: if I have metallic lithium with graphite on one side and on the other side there is something with less lithium, it will try to move from where there is more to where there is less," he detailed.
The crucial point in a battery is not letting the lithium pass as a metal but forcing the lithium to become a lithium ion (Li+) plus an electron. To achieve this, a material is placed in the middle that allows lithium to pass but not electrons. So, with a concentration difference, lithium will try to move from one side to the other, but each time it moves, it leaves an electron on the side it came from, creating a potential difference.
"That potential difference is what I connect to any circuit, and it produces current. That is the idea of how a battery works. Why lithium batteries? Because it is the smallest of all ions, so it is easier to find a material through which lithium can move, and that will give me higher charge efficiency," emphasized Dr. García Sánchez.
The peculiarity with lithium is that if a potential difference is applied in the opposite direction, it can be returned to the original place, i.e., a rechargeable battery can be created. "Low charge, small size, low mass; that makes lithium one of the ideal metals for high power density batteries," noted Dr. García Sánchez.
According to the 2023 Mineral Commodity Summaries by the U.S. Geological Survey, although markets vary depending on the region, it was estimated that 80 percent of lithium was allocated for battery production during 2022, 7 percent in ceramics and glass, and 4 percent in lubricants.
The market frenzy for this mineral, even dubbed "white gold," is driven by batteries, explained Dr. García Sánchez, as they are one of the most direct ways to store electrical energy without the need for radical transformation. "The boom is happening in the transportation sector, as there is a trend to phase out gasoline cars with internal combustion engines. Many European Union nations, Asia, and non-oil-producing countries already have laws stating that from 2035, the production of internal combustion engine cars will cease completely. This implies a shift to electromobility."
According to the U.S. Geological Survey, lithium sources worldwide are distributed as follows: Bolivia, 21 million tons; Argentina, 20 million; Chile, 11 million; Australia, 7.9 million; China, 6.8 million; Germany, 3.2 million; Congo (Kinshasa), 3 million; Canada, 2.9 million, and Mexico, 1.7 million tons.
According to the report "Mining in Mexico: Social, Environmental, and Economic Overview" by the Ministry of Environment and Natural Resources: "This metal is mainly exploitable in three types of deposits due to its ease and because they have the highest concentration of the mineral: 1. The first type is rock deposits with very high concentrations, reaching 0.2-2 percent per ton of extracted material, and in brines (characteristic aquifer deposit of salt flats). 2. Water deposits: their concentration is lower, but extraction costs are much lower, and they are exploited more intensively. 3. The third most common deposit is clays: there, concentrations are much lower than in the previous ones, and extraction costs are higher, being a process that generates uncertainty."
Lithium extraction involves some difficulties, and although the socio-environmental impact is technically considered lower than that of other similar projects, more than 2,000 tons of chemicals are required for extraction. Additionally, for every ton of lithium salts, 2 million liters of water evaporate.
"A significant portion of Mexico's lithium is in the form of clay, and there are no commercially established purification methods. Usually, the composition needs to be studied because, along with lithium, there may be other metals that are interesting and increase the added value of the extraction and purification being carried out," noted Dr. García Sánchez.
According to the report "Extraction and Industrialization of Lithium: Opportunities and Challenges for Latin America and the Caribbean" by the Economic Commission for Latin America and the Caribbean (ECLAC), like any extractive activity, lithium mining also exerts environmental and social pressure on extraction territories, affecting the sustainability of the ecosystems present there.
According to projections by the International Energy Agency (IEA), lithium is the metal that would experience the highest demand growth, potentially multiplying by 13 to 42, depending on the scenario.
The work of Dr. Mario Fidel García Sánchez and his team revolves around various types of energy production, including those that involve lithium. This mineral, he mentioned, is highly unstable and has some very aggressive reactions, to the point that no one could hold a sheet of metallic lithium in their hand because it would automatically oxidize and, in extreme cases, could explode. "This mineral is not stable in the atmosphere; it reacts with whatever is nearby and is very reactive," he informed.
Working with this mineral in batteries takes place in a glovebox chamber created by UPIITA students themselves. "These are chambers that are placed under vacuum, then nitrogen or some other inert atmosphere is injected, and only there can you work with lithium, not where there is oxygen because it immediately reacts and does so violently. How do we handle lithium? Usually in the form of other chemical compounds, generally lithium carbonate."
In the glovebox chamber, Dr. García explained, a press is placed that ends up creating small discs, similar to watch batteries, where lithium is stored under inert atmosphere conditions. The glovebox chamber has devices to introduce or remove materials to break the vacuum without allowing oxygen to enter the working chamber.
"We introduce the materials and can assemble the coin (resembling a watch battery). Once sealed, we can take it out and see how well our material works, no longer isolated but as part of a device," he referred.
One of the changes fore seen by the constitutional reform to the 2022 Mining Law states that "concessions, licenses, contracts, permits, or authorizations in the matter will not be granted." Additionally, it is said that lithium is strategic, and its exploration, benefit, and utilization will be the responsibility of the decentralized body determined by the Federal Executive.
As a result, in August 2022, Lithium for Mexico (LitioMx) was created. In light of this situation, Dr. Mario Fidel García Sánchez emphasized, "It is not clear exactly how far they want to go, whether they intend to seek Mexican technologies, which would be attractive and interesting, especially if we are talking about Mexico as a country that has a strong cultural and educational level in the field of engineering, particularly in the area of mining. The Instituto Politécnico Nacional has many schools where technologies have been developed and where there is a high scientific knowledge. The question is whether that knowledge will be utilized and where it will be focused."
The doctor called for learning from past mistakes, specifically in the case of the utilization of oil and uranium, for which national technology was not developed for extraction, and it was necessary to turn to other nations.
Selección Gaceta Politécnica #167. (October 31st, 2023). IPN Imagen Institucional: Read the full magazine in Spanish here
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