Inspenet, August 12, 2023.
Engineers from the National University of the Center of the Province of Buenos Aires (Unicen) are working on the creation of supercapacitors using used yerba mate , an organic residue that is normally discarded. These supercapacitors have the capacity to store energy and the tests carried out in Spain between April and June, thanks to a grant granted by the Carolina Foundation and the Ministry of Education, had successful results. The main objective is to achieve large-scale production of these devices in Argentina.
“In the framework of my doctoral thesis that I started in 2018, we looked for energy storage materials and the recovery of regional plant residues to produce activated carbons appeared. We investigated which were more abundant in the country and we came to yerba mate, where there were no records of its being used for this particular purpose”, says Florencia Jerez, a UNICEN engineer who is leading the work.
Supercapacitors, which are energy storage devices, have the ability to store and release energy quickly. This implies that both charging and discharging occur quickly. These components are used in devices that require fast starting power, such as smartphones, computers, and even electric vehicles .
Supercapacitors do not act as substitutes for batteries, rather they complement their function. In situations where fast power response is required, supercapacitors come into their own, while conventional device batteries are used when less power is needed over a longer period of time.
To make supercapacitors store energy, it is necessary to use activated carbon, a material that was previously obtained from burning wood. However, the difference between conventional activated carbons and those that are being developed is that the former are derived from mineral carbon or from the felling of trees, practices that are not environmentally sustainable.
Marcela Bavio, a Conicet researcher who leads studies on renewable energies at the University’s Faculty of Engineering, highlights that innovation lies in the use of organic waste such as yerba mate to create these activated carbons.
Along with yerba mate, scientists have also experimented with other discarded plant materials, such as wheat and corn stubble, the remains of the medicinal cannabis industry, the bagasse resulting from beer production, olive pruning and alperujo, a by-product of olive oil extraction.
Thus, it is no longer necessary to undertake new plantings and wait for the growth of the trees, nor is it necessary to extract mineral coal. Instead, this practice is replaced by the use of waste from various industries, which can be processed to transform them into activated carbon.
large scale production
“We have finished the laboratory stage and we had excellent results. Now we are trying to get financing to be able to jump to the next stage, which would be the pilot scale”, says Jerez. The purpose is to achieve a higher volume of production and obtain parameters to know how the industrial scale process would work.
“We want to transfer all this knowledge that we generate to the national industry because, currently, 90 percent of the activated carbons that are used are imported. We want to value the abundant waste in the country to generate new sources of work, new knowledge and produce the least possible environmental impact”, highlights the engineer.
“Developing supercapacitors with materials that are residues from other industries not only allows technological progress in energy storage, but also promotes the management and revaluation of waste, and incorporates the concept of circular economy”, points out Bavio.
Yerba mate in Argentina
According to the National Institute of Yerba Mate, during the period between January and June 2023, more than 138 million kilograms of yerba mate have been distributed in the national market. This figure includes both the volume destined for the distribution points of the yerba producing companies and the acquisitions made by wholesalers, hypermarkets and supermarkets.
Additionally, almost 19 million kilograms have been exported to the international market. The total sum of accumulated sales in these months constitutes the highest figure recorded in the last decade.
Argentina leads the world production and export of yerba mate, followed by Brazil and Paraguay, holding control over 60 percent of the global market.