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Scientists at the Sustainable Energy Laboratory (LaES) at the National University of Córdoba (UNC) have been working with organic waste such as malt, peanut shells and rice to produce biochar for eight years. Now the 30-person team, including researchers Victoria Bracamonte, Guillermina Luque, Andrea Calderón, Daniel Barraco and Ezequiel Leiva, wants to convert a raw material, cow hair, which is abundant in a cattle-producing country like Argentina, into energy by developing lithium-sulfur batteries of the next Generation.
Before the pandemic, scientists began experimenting with cow hair and discovered that it could be a promising raw material. “We got hair from a tannery that smelled like cow piss, Vicky [Bracamonte] She washed her hair for the first time at home in the washing machine and then dried it in the oven in her kitchen. We washed it again in the laboratory with isopropyl alcohol and began the process of extracting the biochar,” says Guillermina Luque, describing the beginnings.
Lithium-sulfur batteries represent the promise of the energy transition on the way to curbing climate change, especially in the automotive market, as internal combustion vehicles are major emitters of greenhouse gases. But although they are being tested in laboratories around the world, they have not yet been commercialized.
“That would be a new generation of batteries that is not yet available on the market. Cow hair is a material that no one has ever used for this purpose,” explains Ezequiel Leiva, who received the Konex Prize this year as one of the 100 most outstanding Argentine scientists of the last decade.
The work is funded by YPF Tecnología (Y-Tec), the main research and development company for the energy sector in Argentina, and the National Council for Scientific and Technical Research (Conicet), with the support of other government institutions.
Leiva expects that industrial-scale development will take about ten years and that lithium-sulfur plants will co-exist with current lithium-ion plants to supply the automotive industry given the boom in electric cars. According to an analysis by PwC and Strategy&, battery electric vehicles (BEVs) accounted for 14.3% of new car registrations in 2022 across 14 major markets, up from just 4.1% in 2020 and 8.2% in 2021. Additionally It is expected that by 2026, the price of electric vehicles will be equal to the price of internal combustion engine vehicles in the most developed countries, says a Statista report. In other words: a sharp increase in demand for batteries is expected. In Norway, 60% of vehicles sold in 2021 were electric vehicles. Six million will be registered in China in 2022. “There will be a revolution in this technology this decade and the next,” says Leiva.
Scientists at the Sustainable Energy Laboratory of the National University of Córdoba have developed a project that uses organic tannery waste to develop a prototype lithium-sulfur battery. Tannery JBS Leather Argentina SA
The value of a waste
The Argentine development, patented in the USA and published in the magazine According to LaES scientists and independent experts, Chemistry Select has at least two outstanding aspects.
On the one hand, the commitment to the circular economy is valued. The new thing is the raw material, an industrial waste that this livestock country produces in large quantities. Cow hair is the main solid waste from tanneries that is thrown away or used to fill floors. It is estimated that for every ton of wet cow hide, 85 kilos of residual hair is created, which makes eight kilos of charcoal. In 2020, 77,000 tons of cowhide were produced, yielding 616,000 kilos of carbon material for the cathode. “It is interesting to add value to something that is useless and can be used in a battery to store energy,” says Luque.
On the other hand, biochar obtained from cow hair leads to a reduction in chemical reactions that produce polysulfides, which weaken the capacity of batteries. The structure obtained after processing these organic wastes would prevent the formation of these undesirable substances. “One of the advantages of cow hair is that it can retain polysulfides, these soluble sulfur species, which prevents the loss of material from this battery,” explains Leiva.
Independent science also sees great potential in this development. Arnaldo Visintin, a professor at the National University of La Plata (UNLP) and senior researcher at Conicet, says it is “a very important contribution.” He also believes that this laboratory work could be developed in the not-too-distant future at UniLiB, Argentina's first national cell pilot factory for lithium-ion batteries – a joint venture between Y-Tec and UNLP – in the city of Berisso, Buenos Aires.
“I think that a lithium-sulfur prototype can be realized in less than ten years,” says Visintin. “The lithium-sulfur battery is the battery of the future, but there are still some problems that this method developed in Córdoba significantly improves, reaching up to one hundred charge-discharge cycles and one thousand cycles with 50% discharge; very good capacity. This is new, it is an important contribution,” says the researcher.
Cattle hair is the main solid waste from tanneries; Scientists are using the organic waste to develop a prototype lithium-sulfur battery. Ramiro Pereyra
What is it about
Current batteries have two electrodes: a graphite anode and a cathode made of cobalt and nickel, expensive and polluting metals. Leiva explains that they want to replace this cathode with one containing sulfur. The lithium-sulfur models would not only be more economical and ecological, but would also have greater autonomy, charging speed and energy density. They would be more sustainable.
The process of making biochar from cow hair is done entirely in the laboratory. The raw material is subjected to a type of “cooking” in two steps. The synthesized biochar is washed and mixed with sulfur, creating a composite material that is used to make the electrodes. Once these cathodes are prepared, they are tested in “coin cells” that use lithium as a counter electrode. This biochar-sulfur composite has specific properties not previously observed in other materials used by researchers. Its micro- and nanoporous structure enables the battery to respond well.
“What’s so special about cow hair? A structure that, when attacked, creates mesopores and micropores capable of retaining sulfur. It has this uniqueness; “Not all materials react the same way,” says Leiva. Sulfur is a non-conductive material that must be covered by a carbonaceous material that precisely gives it conductivity. In this case, it was observed that the battery can store a large amount of lithium with many charge and discharge cycles.
Ezequiel Leiva, Victoria Bracamonte, Guillermina Luque and Andrea Calderón scientists from the Sustainable Energy Laboratory (LaES) of the National University of Córdoba (UNC) who developed the project. Ramiro Pereyra
Leiva assures that batteries of this type will allow future electric vehicles to double their autonomy. “If we transfer it to an electric car, the lithium-ion batteries have reached their maximum possible capacity, a range of around 300 kilometers. With the lithium-sulfur battery, the car could travel 600 kilometers, similar to an internal combustion engine,” agrees Luque. He suggests that one could think about using this type of energy for larger vehicles, even airplanes.
Bracamonte emphasizes that the team's work highlights the contribution that science and technology can make to the development of a country. This not only benefits the internal population, but in this case also positions Argentina as a raw material producer for energy.
Although there is still a long process ahead, including improvements to battery speed and optimization of the process, Leiva believes cow hair is a good candidate. “There is much to do. The interesting thing is that this rather early stage shows that this connection is viable,” he emphasizes.