Cement batteries: Revolutionizing energy storage in homes
The concept of storing energy from renewable sources within building structures has been familiar for centuries. Scientists are currently exploring ways for residential buildings to autonomously store electrical energy, potentially making external storage facilities unnecessary in the future.
Researchers focus on a mixture used since ancient times—cement, water, salt, and soot. This tried-and-tested formula, traditionally used to create durable mortars similar to modern concrete, is now being revisited. These same materials could be employed to construct houses capable of storing electrical energy in their walls, effectively functioning as cement batteries.
How to store energy from renewable sources?
A study published in the Proceedings of the National Academy of Sciences examines efficient methods for storing energy from renewable sources. While these sources are environmentally friendly, their energy output still lacks consistency. For example, solar panels generate large amounts of energy on sunny days but much less on cloudy days. Similarly, wind turbines are most effective only under ideal weather conditions.
A sensible solution to managing energy surpluses in times of high production and shortages during other periods is to develop internal energy storage. Unfortunately, current battery-based solutions are prohibitively expensive, largely due to the use of rare materials. Even batteries repurposed from electric vehicles remain costly and not entirely eco-friendly. In this context, a novel proposal has been introduced by researchers at MIT (Massachusetts Institute of Technology).
The house as a battery
Research conducted at MIT suggests that cement mixed with soot can act as a supercapacitor. Soot, a byproduct of biomass combustion, contains conductive carbon. When combined with cement and water, it creates a conductive network due to the interaction between carbon and the water channels in the cement.
Building on this principle, a wall equipped with metal plates can function as a cement capacitor. During charging, one side becomes positively charged while the other becomes negatively charged. The flow of charges through the carbon network generates electricity that can power household appliances. Alternatively, concrete can be impregnated with readily available electrolytes such as potassium chloride.
Although this solution provides some energy storage on a small scale, its capabilities significantly increase when applied to larger structures. For instance, an entire house using this system could store approximately 36 megajoules of energy (10 kWh), which opens up intriguing possibilities.
