electrolytes

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.

**********

Web Links

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

Wearable technology is an ever-increasing part of our world. Fitness trackers have become commonplace for people of all ages. Smart watches perform a growing range of functions. There are wearable health monitoring systems of many types for assisted living, elderly patients, and people with specific health problems. Virtual reality headsets are increasingly popular and there is now even smart technology footwear that is integrated with smartphones and mapping software.

The adoption of wearable electronics has so far been limited by their need to derive power from relatively bulky, rigid batteries that reduce comfort and even may present safety hazards related to chemical leakage or combustion. To date, there has not been a power source that can stretch and bend the way our bodies do, which would enable electronic designs that people can comfortably wear.

Researchers at Stanford have recently announced the development of a soft and stretchable battery that relies on a special type of plastic to store power more safely than the flammable formulations used in conventional batteries today.

The lithium ion batteries in our phones, computers, cameras and electric cars already make use of plastic electrolytes. These polymer electrolytes are in the form of flowable gels. The Stanford researchers developed a new polymer that is solid and stretchable rather than gooey and potentially leaky. But it still carries an electric charge and maintains a constant power output even when squeezed, folded or stretched to nearly twice its original length.

The prototype battery is thumbnail-sized and stores only about half as much energy for its size as a conventional battery. But the researchers are working to increase both the size and the energy density of the battery.

**********

Web Links

A new stretchable battery can power wearable electronics

Photo, posted November 28, 2016, courtesy of Timo Newton-Syms via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A green battery from industrial waste

Web Links

Stretchable Batteries | Earth Wise

Web Links