Power-Storage-Brick Could Store Renewable Energy Indefinitely

Bricks may seem like an odd choice to store energy, but researchers at Washington University in St. Louis have transformed these common construction materials into a kind of supercapacitor. This technology could allow renewable energy to be stored indefinitely for use when the sun goes down or wind isn’t blowing.

What is the technology behind it?

Fired brick is one of the most durable building materials, with a history dating back thousands of years. It is composed of fused particles of silica, alumina (Al2O3) and hematite (a-Fe2O3). Hematite gives brick its red color and is also a low-cost, naturally abundant inorganic pigment, metal catalyst, and alloy precursor.

Energy storage company Rondo Energy has built a system using bricks to store renewable electricity. Wind or solar power is used to run electric elements, similar to those in your toaster, to heat the bricks to 1,500 degrees Fahrenheit. The resulting hot air can be directed to industrial processes or stored as steam.

The team’s proof-of-concept brick is a supercapacitor, which stores electricity through ions in the inner brick pores. Its six faces are arranged in a checkerboard pattern, with two of the larger faces facing each other during cycling and allowing for an electrochemical contribution by all of the inner brick pores. A nanofibrillar PEDOT coating penetrates the brick pores, forming an ion sponge that stores and conducts electricity.

The system can be charged and discharged many times a day, providing steady energy without generating waste. This can help with grid stability, making it a valuable addition to solar and other renewable technologies. It is also simple to install, with a design that complements many home styles.

How does it work?

Bricks have been around for thousands of years, but scientists are transforming them into energy-storing devices—a move that could add a new function to the omnipresent construction material. Researchers at Washington University in St Louis have developed a way to convert the iron oxide that gives standard brick its red color into a conductive plastic that can hold reversible electrical charge.

The process involves soaking the bricks in acid that dissolved the haematite mineral that gives them their color, then pumping in chemical vapors to react with the iron, turning it into a more reactive form of iron. This allows a web of polymer nanofibers—known as PEDOT—to cover the bricks’ pores, coating them with an electrically conductive surface. The bricks then become supercapacitors—which store electricity more like a battery than a conventional capacitor—and they can be recharged over 10,000 times without losing their ability to hold a charge.

To test their brick batteries, the researchers wired together a few in series and then used them to power an LED light for 10 minutes. They also conducted several other tests, including charging them to 12v-24v-48v-lifepo4-battery 3 volts in just 13 seconds and testing the ability of the bricks to work underwater.

While this is a promising development, the bricks are still a long way from being ready for practical use. Ideally, they would be woven into walls in industrial buildings where solar or other renewable energy is being produced on-site. Then, when the building needs to be powered back up, the stored energy could be tapped to run the lights and other appliances—a process that is more efficient than pumping water uphill for pumped storage hydroelectricity, the method currently responsible for 95% of grid-level energy storage worldwide.

What is the cost?

Bricks are cheap and ubiquitous, but it’s a bit of an intellectual leap to use them as electricity storage. To do that, they need to be heated up to superhot temperatures – something not everyone will want in their home or workplace. There are other ways to store solar or wind energy, though, including thermal storage systems where warm water is pumped into insulated tanks. One such system developed by Rondo Energy has already caught the attention of investors and is starting production in 2020.

This is similar to a storage solution being developed by Energy Vault, which uses the same idea of raising heavy weights and lowering them to generate electricity – but at much lower temperatures. For comparison, a typical refractory brick can be fired up to 700C but only at a few dozen centigrade degrees above ambient.

The bricks used by Julio D’Arcy and his colleagues at Washington University aren’t heated to those levels, but they do need to be hot enough to trigger a reaction that creates an electrically conducting polymer thin film coating the interior pore walls of the bricks. This in turn enables the bricks to absorb and discharge electricity.

The team’s tests show that brick storage can be a fraction of the cost of a lithium-ion battery and even cheaper than a competing technology called iron-air batteries. However, it’s still more expensive than the cheapest of current fossil fuel energy sources, and its ten-day cycling limit will probably keep it from displacing efficient batteries, which can handle 100 hourly cycles or more.

What is the environmental impact?

Bricks are an abundant, cheap and environmentally friendly building material that can be used in a wide range of structures. They can withstand high temperatures and can be molded into many shapes. This makes them an excellent choice for storing heat generated by heavy industry. Alternative energy sources like wind and solar cannot consistently produce the amount of heat needed to run factories, which are one of the biggest sources of greenhouse gases. Moreover, conventional bricks can store a significant amount of energy.

Scientists at Washington University in St Louis have developed a method for turning ordinary bricks Solar power bank into energy storage devices. They pumped a series of gases into the bricks and used a conductive polymer called PEDOT to coat the bricks’ internal porous structure. This process turned the bricks from their normal red color to a dark shade of blue, and left them riddled with a network of conductive PEDOT nanofibers that can be used to store and discharge electricity.

This is a simple and straightforward system that could be used to store excess wind and solar power indefinitely until it’s needed. It does not require any extra equipment and uses common materials like dirt and sand, even solid waste, to make the bricks. It also does not use ten times the steel and concrete that renewables use, nor does it require any lithium or cobalt. It has one of the lowest carbon footprints of any energy storage system.