Katerina Ioannidou: From Soft Physics to Concrete Applications

A physicist specializing in concrete. Katerina Ioannidou admits that her research topic may come as a surprise.“I thought it was very strange when I was offered a thesis on the physics of cement,” recalls the researcher at the Laboratory of Mechanics and Civil Engineering, describing it as an ordinary material that she initially foundnot “exotic” enough. “But ultimately, it’s a fascinating material, very difficult to study and model, because you’re never sure exactly what you’re working with,” she adds. This complexity stems from the multitude of chemical reactions occurring within the cement. At first glance, the subject seems ill-suited for physicists, who typically prefer more predictable materials.

He was right to continue exploring such complex materials. His understanding of their fundamental principles, modeled using statistical physics, earned him a CNRS bronze medal in 2024. His work is of great interest because it can be applied to energy storage solutions and_CO2 sequestration in cement. These are enormous industrial challenges, given that cement—the main component of concrete, in which it serves as a binder—is the most widely consumed material in the world. Its production generates 7% of global carbon dioxide emissions ( GCCA figures). To reduce this footprint, Katerina Ioannidou’s research explores two avenues. First, creating multifunctional building materials capable of storing energy.

Turning a concrete block into a battery

“For example, concrete lamps that could store energy generated by renewable sources and release it in the form of light,” explains the physicist, who began working on a concrete supercapacitor while doing postdoctoral research at the Massachusetts Institute of Technology (MIT) in Boston, in an international laboratory affiliated with the CNRS.

Thanks to the Momentum program launched in 2016, she is funding her project on concrete designed for energy-self-sufficient buildings. The idea is to harness the porosity of cement by filling it with carbon black (or porous carbon), an inexpensive material whose properties make it possible to transform a concrete block into a battery. More specifically, the conductivity and porosity of carbon black allow it to be charged with ions, enabling electrochemical energy storage. This work was recognized with a patent in 2017 and a position at the CNRS the following year.

Katerina Ioannidou is also working on another application:_CO₂ sequestration in cement. The idea is to accelerate the carbonation process, a reaction with carbon dioxide that binds it. While this reaction occurs naturally, it is very slow. Thanks to the properties of carbon black added to the cement, the reaction no longer takes decades but only a few weeks.“These solutions are not yet deployed on a large scale and do not solve everything. But they already have the merit of showing manufacturers the scale of the problem,” comments Ioannidou, who is working in particular with the Greek cement manufacturer Titan on nanoporous cements.

The Physics of Soft Matter

Since completing her thesis in the civil engineering department at ETH Zurich, the researcher has been exploring the industrial applications of her research. She explains that she was happy to trade the theoretical physics she studied during her master’s degree at Utrecht University in the Netherlands for soft matter physics. “It’s applied physics where I can apply my numerical modeling work to the materials around me. At first, discussions with engineers weren’t easy because they’re less interested in understanding the mechanisms than in practical results. But these exchanges were a great exercise in finding a common language.”

Having begun her career with a tour of Europe—earning a bachelor’s degree in Greece, where she is from, a master’s degree in the Netherlands, a PhD in Switzerland, and then spending time in the United States before coming to work in France—she finds something unique about research in France:“Here, I really appreciate the collaboration among researchers; relationships are more open and less competitive than in countries where the Anglo-Saxon model dominates. The main drawback, however, is access to funding.”