Cement batteries: The future of self-sufficient homes
A technology that enables energy storage from renewable sources within buildings has been known for centuries. Scientists are working toward making residential buildings capable of autonomously storing electrical energy in the future, eliminating the need for external storage facilities.
Researchers focus on a mixture used since ancient times: cement, water, salt, and soot. This proven formula, utilized for years to create durable mortars similar to modern concrete, is now the subject of renewed research. It turns out that these same materials can be used to construct houses with walls that store electrical energy, functioning like cement batteries.
How to store energy from renewable sources?
Research published in the Proceedings of the National Academy of Sciences focused on efficient methods of storing energy from renewable sources. Although these sources are environmentally friendly, they still lack stability. Photovoltaic energy is abundant on sunny days but decreases on cloudy ones. Similarly, wind turbines operate optimally only under suitable weather conditions.
The most sensible solution to the problem of energy surpluses during production periods and shortages during others is to have internal energy storage. Unfortunately, current battery-based solutions are costly due to the use of rare materials. Even those made from used electric vehicle batteries remain expensive and not entirely eco-friendly. In this context, an innovative proposal arises from researchers at MIT (Massachusetts Institute of Technology).
The house as a battery
Researchers at MIT concluded that cement mixed with soot can form a supercapacitor. Soot, a product of biomass combustion, contains conductive carbon. Mixing cement with water and soot allows for the creation of a conductive network through the interaction of carbon with water channels in the cement.
Based on this principle, a wall with embedded metal plates becomes a cement capacitor. Charging causes one side to gain a positive charge and the other a negative charge. The flow of charges through the carbon network generates electricity that can power household appliances. Alternatively, concrete can be saturated with readily available electrolytes like potassium chloride.
Although this solution stores some energy on a small scale, its capabilities are significantly greater in larger structures. When applied to an entire house, such a system could accumulate about 36 megajoules of energy, opening up interesting possibilities.
