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Red bricks are commonly used for constructing buildings but are seldom utilized elsewhere. A research team at Washington University in St. Louis, US, has designed “smart bricks”, which can store energy similar to that of a battery. The application of such materials can bring about a revolution in the construction industry and to our energy-dependent lifestyles.
Scientists around the world are working on finding innovative ways to store energy. The discovery of smart bricks would aid in the preservation of the environment and resisting the rapid climatic changes through the restrictive use of renewable energy.
How Are Smart Bricks Designed
Red bricks are the most commonly available, cheap building material that has been in use for more than 1,000 years. Buildings and walls made of bricks occupy a lavish amount of space, which could be effectively modified and utilized differently through the storage of electric power, similar to that of batteries.
Several designers and architects have recognized the capability of red bricks to absorb and store solar heat, and this property is used as a thermal mass for maintaining a heating and cooling effect.
The team of researchers at Washington University published a proof-of-concept in Nature Communications, stating how a brick could directly power a green LED light. Their publication showed how an ordinary red brick could be converted into an energy storage device, known as a supercapacitor.
Supercapacitors store electricity as a static charge in solids, unlike batteries that store electricity via an array of chemical reactions. The main advantages of supercapacitors are that they can be charged and recharged much faster than in the case of batteries. They also always hold a small fraction of energy, unlike batteries.
Julio D'Arcy, an Assistant Professor of Chemistry and one of the authors of the study, said that their method for the development of smart bricks can also be effectively employed on regular bricks or recycle bricks. D'Arcy further stated that their research was conducted on bricks bought at Home Depot in Brentwood (Missouri), and each brick cost around $0.65.
Conversion of a Normal Brick to an Energy Storing Brick
Scientists have developed a coating made up of conducting polymer PEDOT (3,4-ethylene dioxythiophene). PEDOT is composed of nanofibers that can penetrate the internal porous network of a brick. The polymer coating remains confined in a brick and acts as an ion sponge that could store and conduct electricity. The iron oxide or rust imparts the red color to the bricks.
This metal oxide plays an essential role in stimulating the polymerization reaction. The reactions turn the red bricks into a dark blue color. The researchers stated that these smart bricks could store a substantial amount of energy.
As mentioned earlier, scientists utilize the porous nature of the fired bricks in the development of the new technology. These pores are filled with nanofibres of a conducting plastic that can store charge. The researchers at Washington University are optimistic that with an increase in the energy density of the smart bricks, they can establish a low-cost alternative to the commonly used lithium-ion batteries in the future.
At present, as reported in Nature Communications, the energy density of the first power bricks is 1% of that of the lithium-ion batteries. The research team believes that the capacity can be increased tenfold by the amendment of specific metal oxides. They can be used commercially by increasing the charge storage capacity of the bricks.
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Mechanism of Energy Storing Bricks
The red brick can regulate oxidative radical polymerization and deposition of a nanofibrillar coating of PEDOT. The main properties that make fired brick an ideal substrate for the development of stationary supercapacitors and electrochemical PEDOT electrodes are:
- Mechanical robustness
- ~8 wt% α-Fe2O3 content
Owing to the above-stated properties of the fired bricks, a five-minute epoxy works as a waterproof case supporting the function of the supercapacitors when they are submerged underwater. A gel electrolyte increases the cycling stability to 10,000 cycles with ~90% capacitance retention.
Scientists claimed that the charge stored by the first bricks is too small and, therefore, one does not feel any shock when touched. However, a wall of connected bricks would require an insulating coating.
Advantages of Smart Bricks
PEDOT coated bricks can provide electric power to emergency lighting. D'Arcy said that around 50 bricks connected with solar cells could power emergency light for five hours. These coated brick walls acting as a supercapacitor could be recharged multiple times within an hour and be cycled 10,000 times before their capacity falls significantly.
Scientists such as Dan Brett, Professor of Electrochemical Engineering at University College London, UK, and Richard McMahon, Professor of Power Electronics at the University of Warwick, UK, highly appreciated the research demonstration. However, both Professors believe that extensive future work is required before commercial application.
References and Further Reading
Washington University in St. Louis. (2020) Storing energy in red bricks. ScienceDaily. Retrieved September 3, 2020 from www.sciencedaily.com/releases/2020/08/200811120154.htm
Wang, H., et al. (2020) Energy storing bricks for stationary PEDOT supercapacitors. Nature Communications. 11,1. DOI: 10.1038/s41467-020-17708-1