Researchers at MIT are advancing an experimental form of concrete that can store and release electrical energy, potentially turning everyday structures into massive energy storage devices. The material, called electron conducting carbon concrete, or ec3, is made by combining cement, water, ultra-fine carbon black, and electrolytes to create a conductive “nanonetwork” inside the concrete. This network acts like an electrode, enabling walls, sidewalks, and bridges to function similarly to giant batteries while still serving as load-bearing elements in buildings and infrastructure.
Until now, ec3 has been constrained by low voltage and scalability issues, limiting its usefulness as an energy storage solution. In their latest work, the MIT team behind ec3 reports that they have increased the energy storage capacity by an order of magnitude. With the improved technology, about five cubic meters of concrete, described as the volume of a typical basement wall, could store enough energy to meet the daily needs of the average home. The researchers achieved this step by using high-resolution 3D imaging to better understand how the conductive carbon network interacts with electrolytes and then systematically testing different electrolyte types and concentrations.
The team found that there is a wide range of electrolytes that could be viable candidates for ec3, including seawater, which they suggest could make the material attractive for coastal and marine uses such as support structures for offshore wind farms. They also streamlined how electrolytes are added to the concrete mix, which allowed them to cast thicker electrodes capable of storing more energy. Although ec3 does not match conventional batteries in terms of energy density, it can in principle be integrated directly into architectural components and last as long as the structures themselves. To demonstrate this integration of structural performance and energy storage, the researchers built a small arch made of ec3 that supported its own weight and an additional load while powering an LED light.
