The use of elements such as lithium, cobalt and nickel to make batteries means dependence on rare (and therefore, expensive), toxic materials whose extraction and processing cause many environmental problems; Two million liters of water are needed to extract 1,000 kg of lithium. Researchers are urgently looking for alternatives that are abundant, renewable, biodegradable, safe and have low cost and environmental impact. The solution may be closer: sodium and calcium, two elements …
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The use of elements such as lithium, cobalt and nickel to make batteries means dependence on rare (and therefore expensive), toxic materials whose extraction and processing cause many environmental problems; Two million liters of water are needed to extract 1,000 kg of lithium. Researchers are urgently looking for alternatives that are abundant, renewable, biodegradable, safe and have low cost and environmental impact. The solution may be close: sodium and calcium, two abundant elements studied for prevention According to EU projections, demand for lithium will increase by 60% in two decades.
The unstoppable proliferation of home and portable devices has two major challenges: the electrification of mobility and the storage of renewable energy to provide continuous power. “There just isn’t enough lithium, cobalt and nickel ions to meet everyone’s needs,” says John Abo-Rjaili, from Tiamat Energy. National Center for Scientific Research of France (CNRS).
This Doctor of Physics and Chemistry examines the material according to which he publishes the horizon, an alternative to sodium, is one of the most abundant chemical elements in the Earth’s crust, and its processing and use, unlike lithium, is safer and cheaper. On the contrary, it requires a large volume, which is why current developments are not yet suitable for small devices.
They cannot compete with the range that current storage systems bring to electric cars. But they can act as substitutes on shorter routes, the majority. “I would never challenge lithium-ion batteries for 500 kilometers, this type of sodium-ion is very competitive for short stretches. They are cheap for short and medium distances in a car,” explains Apo-Rjaili.
Researchers from Chalmers University of Technology (Sweden) and Delaware (USA) are on the same track, according to a published study. Energy. “There is a tendency to demand a really big battery. But according to research, in general, something slightly smaller than the range of the petrol tank is enough, because the only time you need more autonomy is for a trip of six hours or more. , the driver can charge during the journey. Really more emphasis on the need for long distances is a given, and this leads to increased vehicle costs and greater resource use for electric cars,” says Chalmers’ Professor Francis Spree.
For this physician in energy and the environment, this mindset shift is necessary to replace the charging facilities where people spend most of their time: at home and at work. Instead, Spree laments that many European countries are focusing on charging networks on roads and tracks.
This simple change in requirements will further promote sodium as an alternative, as it will allow renewable sources to be used as energy storage systems in homes and workplaces. Magdalena Graczyk-Zajac, a professor at the Technical University of Darmstadt in Germany and a member of the European project, works in this sense. SimbaIts first phase will be completed next June.
You can drive for free for eight or nine months a year
Magdalena Gracik-Zajac, Professor at the Technical University of Darmstadt
The researcher is committed to storing the energy captured by home photovoltaic panels in a rechargeable sodium ion domestic battery. This will provide electricity to homes and reduce the cost of electric vehicles for its residents significantly. “You can drive for free for eight or nine months a year,” he says. The prototype is already in laboratory tests.
One part, the anode, is made of hard carbon, which is derived from wood or other biological waste. For the cathode, Prussian white is tested, a chemical compound from a blue pigment of the same name, but one of the metals rich in sodium and iron.
Center for Basque Research CIC Energygun, has its own development in this area: a sodium metal anode with a thickness of seven microns (70 times thinner than the current one) achieved through a physical evaporation process. “This breakthrough,” according to the center, “opens the door to the production of flexible solid-state batteries with a flexible sodium anode, a safer, cheaper and smaller alternative to current batteries with liquid electrolytes that use graphite.”
“Sodium cannot be easily laminated due to its plasticine-like adhesive structure,” explains Montes Calceron, principal investigator of the project, to CIC energiGUNE. “To date, the most common method used to roll a block of sodium is as basic as processing it with a hammer, but this means that a thin and uniform sheet cannot be obtained, therefore, there was a lot of unused sodium in batteries. Due to evaporation, we were able to overcome that obstacle,” He says.
Thinning this anode helps reduce the amount of sodium required and the batteries’ costs, weight, and dimensions, while increasing energy density (higher storage capacity) and safety.
If the raw material is cheap, the batteries can be cheap too
Rosa Palacin, Institute of Materials Science of Barcelona (ICMAB-CSIC)
Another element used as an alternative to lithium is calcium. “It is one of the most abundant elements in the Earth’s crust, and it is not concentrated in specific geographical areas like lithium. If the raw material is cheap, the batteries will be cheap,” says Rosa Palacin, from Barcelona’s Institute of Materials Science (ICMAB-CSIC) and a member of the project. Corbett A the horizon.
Using calcium as the negative electrode offers advantages over graphite in lithium-ion batteries because it has a higher accumulation capacity per kilogram (energy density) than conventional lithium batteries, forming small solid structures called dendrites that can cause short circuits or explosions. After several uses, according to the company.
“When calcium passes through the electrolyte, two electrons are released instead of one, as with lithium. As long as a suitable positive electrode is found, it can be assumed that a battery of the same size will provide more autonomy if used in an electric vehicle,” explains Balacin.
The main thing is to choose the most suitable components. “All electrolyte salts that work in the end seem to contain boron. We use calcium tetrafluoroborate dissolved in a mixture of ethylene and propylene carbonate,” says the researcher.
Other researchers at the Technical University of Denmark are looking into the project Chalpage, A battery made from an aluminum anode and a sulfur cathode. Aluminum is more abundant than calcium, but adding it to a battery poses similar difficulties.
“All the materials used are cheap. Aluminum, sulphur, electrolyte and urea are very, very cheap. Even the polymer,” says Danish University researcher Juan Lastra, who defends this option of storing energy from wind or solar parks.
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