A ‘Living Cement’ Powered by Bacteria Turns Walls into Energy-Storing Batteries

Concrete, a material old of two millennia

Used for more than 2,000 years, notably by the Romans who have mixed lime, volcanic ash (puzzolane) and water, concrete has become the reference in terms of building materials.

We find it all around us, whether on the roads, the buildings or the statues. If concrete is known for its solidity and gray color, researchers work to develop a new version of this material, by creating “living cement”.

Being one of the main components of concrete, the cement serves as a binder, forming a sticky paste when mixed with water, which will adhere with sand and aggregates, making the concrete solid and resistant.

Cement mixed with … a bacteria

In a study published on September 09 in the journal Cell Physical Science Reports, A team of researchers from the universities of Aarhus, Denmark, and Chongqing Jiaotong, China, explains that he has managed to integrate the bacteria Shewanella Oneidensis, In hardened cement, which contains sodium sulfate powder, an electrolyte highly appreciated by bacteria.

This bacteria was not chosen at random, since it is an electroactive organism, which means that it is capable of transferring electrons outside its cell, generally towards a conductive surface like an electrode.

The researchers explain that this “microbial supercapacitor”, resulting from the connection between the cement and the bacteria Shewanella Oneidensis, reached an energy density of 178.7 wattheures per kilogram (WH/KG). A kilo of this new cement would be able to supply 44 LED bulbs with such a quantity of energy, reports Iflscience.

Effective concrete in all circumstances

In addition to its performance to create energy through microorganisms, cement has shown that it was able to keep 85 % of its capacity, despite having been used for 10,000 cycles. The researchers also indicate in their study that even after the death of microbes, the system continues to store energy, and a reactivation by nutrients makes it possible to restore up to 80 % of its capacity.

“The result is a new type of material capable of both supporting loads and storing energy, and finding its performance when powered by nutrients”, said Qi Luo, a researcher at the University of Aarhus and the main study of the study.

Concrete, formed from this new cement, has remained functional and effective at various temperatures. The results have indeed shown that the storage of loads continued both at negative temperatures (-15 ° C) as in environments at typical room temperature (20 ° C to 33 ° C).

Although this innovation is still far from being ready for use, especially due to the natural alkalinity of cement which by its very high pH represents a hostile environment for many bacteria, it however opens the way to buildings capable of storing their own energy.

“We plan to integrate this technology into real buildings, in walls, foundations or bridges, where it could support renewable energy sources such as solar panels by ensuring local energy storage”, said Qi Luo, in remarks reported by Iflscience.

Source: Iflscience