Technology that enables ethanol-powered electric cars could accelerate the energy transition

In a review article, researchers highlight the challenges that must be overcome to increase the performance and lifetime of MS-SOFC fuel cells while reducing the cost and environmental impact.

Agência FAPESP* – In an article published in the Journal of Energy Chemistry, researchers from the Center for Innovation in New Energies (CINE) and collaborators provide a detailed review of the advantages and challenges of a promising fuel cell technology, that of MS-SOFCs (metal-supported solid oxide fuel cells).

According to the authors, this technology, which has attracted interest in academia and industry over the past two decades, could help accelerate the energy transition in the automotive sector, especially in countries with extensive production and marketing of biofuels, such as Brazil, the United States, Thailand, India and some African nations.

“Our study highlights that MS-SOFCs are a promising solution for the decarbonization of mobility, and could be an effective alternative for the electrification of this sector,” says Gustavo Doubek, professor at the State University of Campinas (UNICAMP) and member of CINE – an Engineering Research Center (ERC) supported by FAPESP and Shell. “They combine high efficiency, durability and fuel flexibility, as well as eliminating the current limitations of electrification, creating a solid path for the energy transition of the automotive sector, without the high costs of hydrogen or the limitations of conventional batteries in recharging time,” he adds.

The review article is the result of a collaboration between researchers from UNICAMP, the Mackenzie Institute for Research in Graphene and Nanotechnologies (MackGraphe), the Federal University of Espírito Santo (UFES) and the King Abdullah University of Science and Technology (Kaust, Saudi Arabia). The team was supported by FAPESP through four projects (22/02235-4, 17/11958-1, 17/11986-5 and 14/02163-7).

The research is part of a larger effort conducted within CINE focused on finding viable technologies to decarbonize the transportation sector, which includes work on new materials and architectures for MS-SOFCs, as well as research on reformers and biofuels.

“CINE’s differential is not only in its research, but also in its search for a link between science and the market,” explains Hudson Zanin, also a professor at UNICAMP, researcher at CINE and co-author of the article. “The center is working to take these innovations from the laboratory to real-world applications, ensuring that MS-SOFCs are fully demystified and become a practical and affordable solution in the energy transition,” he adds.

According to the researchers, MS-SOFC has a number of advantages over other mobility systems. Compared to conventional ethanol cars, MS-SOFC cars are more energy efficient. In other words, with the same amount of biofuel, a fuel cell car can drive more kilometers than an internal combustion engine car. In addition, electric cars are quieter, reducing noise pollution, and more comfortable for drivers and passengers.

Compared to battery-electric cars, the fuel-cell vehicle stands out for the speed at which the tank can be filled compared to the time it takes to recharge the battery. Another advantage is that it does not overload the power grid.

In addition, MS-SOFCs are capable of generating electricity from bioethanol, biogas, biomethane, green ammonia and even fossil fuels. Thus, compared to a hydrogen car, the MS-SOFC vehicle wins in terms of practicality because it can be filled with widely available and easily transportable fuels, while hydrogen refueling stations are still very scarce.

Finally, the fuel cell’s robustness and low cost compare favorably with other solid oxide fuel cells (SOFCs) that use only ceramics instead of metals to support the device.

Ethanol generates hydrogen that generates electricity

A car powered by MS-SOFCs can operate as follows: the tank is filled with a renewable fuel, such as ethanol produced from sugarcane; this passes through the reformer, the component responsible for “extracting,” through chemical reactions, the hydrogen that is present in the composition of the biofuel. The hydrogen, in turn, passes through the fuel cell, where it is oxidized and, together with the reduced oxygen in the air, generates the electrons needed to charge the batteries and supercapacitors and power the electric motor.

The waste products of the process are water, heat and a small amount of carbon dioxide (CO₂), which is offset by the CO₂ consumed by the sugarcane in photosynthesis, so that net carbon emissions are close to zero.

The technology is not yet available in vehicles for sale on the market, but it has been used in a prototype of Nissan’s ethanol electric car, the “e-Bio Fuel Cell,” which was launched in Brazil in 2016.

However, MS-SOFCs still pose challenges for research and development to become commercially viable in terms of performance, durability and cost. These challenges, as well as the current state of development of the technology, can be seen in the recently published study, which was also funded by UNICAMP, the National Council for Scientific and Technological Development (CNPq) and Shell, with strategic support from the National Agency for Petroleum, Natural Gas and Biofuels (ANP).

The article “Reviewing metal supported solid oxide fuel cells for efficient electricity generation with biofuels for mobility” can be found at: www.sciencedirect.com/science/article/abs/pii/S2095495624007848?via%3Dihub.