Researchers Create Living Cement for Energy Storage

A research team from Aarhus University in Denmark has developed a novel type of cement infused with live bacteria, enabling it to function as a supercapacitor for energy storage. This innovative material could allow building walls to store electricity generated from renewable energy sources.

The study, published in Cell Reports Physical Science, introduces the concept of living cement as a means of energy storage. This development is currently in the proof-of-concept phase, demonstrating the feasibility of the idea rather than presenting a fully realized product.

The researchers incorporated Shewanella oneidensis, a type of exoelectrogenic bacteria, into the cement. These bacteria can survive in both oxygen-rich and oxygen-poor environments, utilizing metals or specific organic transporters instead of oxygen. Through metabolic processes, the bacteria transfer electrons to electron acceptors, facilitating electron transfer.

Within the cement, the bacteria proliferate and form a network of charge carriers capable of storing and releasing energy as needed. The biohybrid system exhibits an energy density of 178.7 Wh/kg and a power density of 8.3 kW/kg, significantly surpassing the performance of existing cement-based capacitors. The researchers estimate that a room constructed with this cement could store approximately 10 kWh of energy.

Practical tests conducted by the researchers involved connecting six cement blocks, which were able to power an LED lamp with the stored energy. Remarkably, this operation was successful under extreme temperature conditions, ranging from a minimum of -15 °C to a maximum of 80 °C. The system maintained its capacitor capabilities, achieving optimal performance at around 33 °C.

However, the bacterial activity diminishes over time as nutrients are depleted. To address this, the researchers integrated a microfluidic system into the cement, which provides the bacteria with proteins, vitamins, salts, and growth factors. This system allows for the restoration of approximately 80% of the original storage capacity.

The researchers envision applications for this living cement in the construction of walls and bridges, which could serve as renewable energy storage solutions. This approach may enable the local and cost-effective storage of electricity generated from renewable sources such as solar and wind energy, potentially reducing the reliance on expensive batteries.