Senegal: biomass, a hope for storing energy

From an oven at 300 ° C, Sokhna Dieng takes out pieces of nickel and cobalt carefully deposited on a glass dish. In the two small air-conditioned rooms of the physics department laboratory at Cheikh Anta Diop University (UCAD) in Dakar, the master 2 student in physics moves between fifteen modern machines lined up on tables. Brand new equipment around which other students in white coats are busy, attentive to their experiments.

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Since the installation and equipment of this laboratory, in 2019, thanks to funding of 230 million CFA francs (350,000 euros) from the Royal Society of London, the students of the M2 in physics and their professor, Balla Diop Ngom , work on the exploitation and valorization of local biomass. For them, it is a question of selecting, from among all the organic materials available in Dakar and its surroundings, those that will allow energy storage, that is to say to manufacture cells and batteries.

Master 2 physics students at Cheikh Anta Diop University in Dakar, Senegal, are working on the design of the batteries of tomorrow in the university's laboratory on November 19, 2021.

The race to design miniature batteries is being played out globally. To reduce their weight, increase their energy density or their charging power, Europe is mobilizing with a program called Battery 2030 +. Senegal too. Among UCAD’s research axes are solid batteries, in which the liquid electrolyte of conventional batteries is replaced by a solid conductor. The advantages are numerous: they combine better thermal stability, more on-board energy density, reduced loading time and a reduction in the environmental impact of manufacturing processes. So many advantages that the university laboratory considers ethical, at a time when it is urgent to find the least greedy energy possible.

Peanut and hibiscus shells

Ndeye Maty Ndiaye, Young Talent Sub-Saharan Africa of the For Women in Science 2021 L’Oréal-Unesco program, will dedicate the endowment of his prize to the purchase of equipment and chemicals for his laboratory. Specializing in vanadium oxide nanoparticles since her master’s degree at UCAD, she prepared her doctorate in South Africa, thanks to a scholarship funded by the Organization for Women in Science for the Developing World (OWSD ). At 38, she is now a postdoctoral research assistant.

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Ndeye Maty Ndiaye has two dreams. First of all, “Solve the problem of access to energy in all developing countries, and particularly in Senegal …”, explains the researcher. She would like to “Also to motivate girls and young women to make their dreams of science, technology, engineering or mathematics come true”. She returned to Senegal to continue her research with Professor Ngom, after defending her thesis in 2019.

Samples of natural and local raw materials such as cashew leaves, peanut shells and bamboo, which can be used for energy storage and seen at the laboratory of the University Cheikh Anta Diop in Dakar, Senegal, on the 19th November 2021.
In the physics laboratory at Cheikh Anta Diop University in Dakar, Senegal on November 19, 2021.

Because here, the research wants to be sober as much as ethical. In Professor Ngom’s lab, students implement technologies that do not emit carbon dioxide and “Distribute the different raw materials to be tested, such as peanut shells, hibiscus, bamboo or cashew leaves”, explains the researcher. Already, the work of his team has shown that hibiscus can store energy six times more efficiently than what exists on the market at the moment. They owe these results to the calculations of a large blue machine connected to a computer, whose screen is covered with colored graphics. It remains to calculate the charging and discharging time of the battery to know if this product can be marketed.

Fair access to clean energy

Professor Ngom insists on the frugality of his research, which uses raw materials present in Senegal and aims to develop renewable energy whose transformation generates little carbon dioxide. “We want a technology that preserves the environment and brings more equity in access to clean energy”, ambitions the physicist. The team therefore strives not to transform products necessary for food, but rather agricultural waste and residues.

On a bench, flasks contain different extracts of the biomass. “We must always be careful, because we handle toxic products which can damage the hands of researchers”, notes Professor Ngom, who integrates respect for the safety of his teams into his professional ethics. This is the reason why the laboratory has invested in a “glove box”, a Plexiglas box in which large gloves are attached. As Professor Ngom explains, “This device creates a vacuum to work with materials and nanoparticles that must not come into contact with oxygen. And it also avoids producing CO2 during our research “, he adds.

Ndeye Maty Diop went to the United States, to the University of Philadelphia, to train in the use of this new equipment. More than ever, the laboratory is counting on partnerships with other universities in South Africa, Canada, Brazil and the United States, to gain access to instruments that it does not yet have. A way of pooling research and thus being more efficient and ethical at the same time.

Ibrahima Gningue, a physics student, observes the state of a solution of distilled water and peanut shells that he intends to use to store energy, in the laboratory of the Cheikh Anta Diop University in Dakar, in Senegal on November 19, 2021.

“In research, there are rules to follow and behavior to adopt. Being in contact with nanoparticles, which are for some dangerous, requires physical and mental preparation ”, specifies Ndeye Maty Ndiaye. For her, ethics also involves respect for the members of the research team, the sharing of knowledge and solidarity. A revenge on a part of her entourage who, when younger, had discouraged her from embarking on science, arguing that it was “Way too complicated for a girl”.

File produced in partnership with the L’Oréal Foundation.

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Senegal: biomass, a hope for storing energy