battery technology

A green battery from industrial waste

February 11, 2025 By EarthWise Leave a Comment

Flow batteries are rechargeable batteries in which liquid electrolytes flow through one or more chemical cells from one or more tanks. The electrolytes are redox pairs, that is, chemical compounds that can reversibly undergo reduction and oxidation reactions. The most common redox electrolytes include elements like vanadium, chromium, iron, zinc, and bromine. Flow batteries can provide large amounts of both electrical power and stored energy based on the size of the electrolyte tanks. As a result, they can be scaled up far more readily than other battery technologies.

Flow batteries are safe, stable, long-lasting, and their electrolytes can easily be refilled. They have significant potential for use in utility-scale storage for renewable energy systems.

Researchers at Northwestern University have developed a redox flow battery based on an organic industrial-scale waste product. The material – triphenylphosphine oxide or TPPO – is produced in the thousands of tons each year. It is byproduct of producing a variety of substances including some vitamins, pharmaceuticals, agrochemicals, and other bulk chemicals. For the most part, TPPO is of little use and must be carefully discarded.

The current market for redox flow batteries is very small but is expected to grow over time as the need for utility-scale energy storage continues to expand. A battery technology based on a waste material that is already produced in high volume and that must otherwise be disposed of with caution would have significant advantages.

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Green battery discovery turns trash into treasure

Photo, posted January 12, 2015, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wireless car charging

April 17, 2024 By EarthWise Leave a Comment

It’s increasingly common to see cars hooked up to charging cables in shopping centers, rest stops, and dedicated charging stations. Charging electric cars is easy to do, just like charging phones and laptop computers. These days, it is pretty common to charge phones without using any charging cable at all because of the availability of wireless charging technology. The same thing may well happen with electric cars.

A team of researchers at Oak Ridge National Laboratory has successfully demonstrated wireless charging of electric cars with high efficiency and fairly fast charging speed.

The patented system was used to charge up a Hyundai Kona EV using electromagnetic fields, which is essentially how phone chargers work. The technology makes use of a polyphase electromagnetic coupling coil, which is lightweight and small. Rotating magnetic fields generated in the coil’s windings boost the power available. The system provided 100-kW of power with 96% efficiency. That isn’t as powerful as the fastest high-speed charging stations, but it is considerably more than any home charging solution can provide. For many vehicles, such a charger could provide 50% battery capacity in less than 20 minutes.

Battery technology continues to improve leading to larger capacity, faster charging, longer battery life, and lower cost. At some point, charging up an electric car will take no more time than pumping gas.

The Oak Ridge researchers consider this development to be a breakthrough achievement that could open the door to fast and efficient wireless charging for electric passenger vehicles. One could imagine having the ability to drive up to a charging spot and charging up the battery without even getting out of the car.

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Charging up the commute

Photo, posted July 12, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better Batteries For The Grid | Earth Wise

September 14, 2021 By EarthWise Leave a Comment

As more and more solar and wind power is added to the electric grid, the need for ways to store the energy produced increases. Using batteries for this purpose is increasingly popular, mostly driven by the improving economics of the lithium-ion batteries used in electric vehicles as well as consumer electronics.

There are other battery technologies besides lithium ion that are not suitable for use in automobiles and cell phones but have potential advantages for the grid. One such technology is molten sodium batteries. These batteries have high energy density, a high efficiency of charge and discharge, and a long cycle life. They are fabricated with inexpensive materials and they are especially suitable for large-scale grid energy storage because their economics improves with increasing size.

A drawback of molten sodium batteries is that they operate at 520-660 degrees Fahrenheit, which adds cost and complexity. Researchers at Sandia National Laboratories have designed a new class of molten sodium batteries that operates at a much cooler 230 degrees Fahrenheit instead.

The battery chemistry that works at 550 degrees doesn’t work at 230 degrees. The Sandia group developed something they call a catholyte, which is a liquid mixture of two salts, in this case sodium iodide and gallium chloride. (Gallium chloride is rather costly, so the researchers hope to replace it in a future version of the battery).

By lowering the operating temperature, there are multiple cost savings including the use of less expensive materials, the requirement for less insulation, and the use of thinner wire.

This work is the first demonstration of long-term, stable cycling of a low-temperature molten-sodium battery. The hope is to have a battery technology that requires fewer cells, fewer connections between cells, and an overall lower cost to store electricity for the grid.

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