Stanford researchers are trying a new combination of material to be used in a rechargeable battery to store large amount of solar and wind energy affordably at room temperature.
If successful, the new technology, with further development, could deliver energy to the electric grid quickly, cost effectively and at normal ambient temperatures.
For the past many years, researchers have been experiments to develop a flow battery that would store intermittent renewable energy obtained through sun, wind, and other sources. However, scientists have got little success so far in this area. The liquids that could produce the electrical current have been limited either by the amount of energy they could deliver or they require extremely high temperatures. Some of them use very expensive/toxic chemicals.
The new research is being carried out by William Chueh, assistant professor of materials science and engineering at Stanford, along with his PhD students Antonio Baclig and Jason Rugolo.
The team tried a combination of sodium and potassium as the fluid for the negative side (electron donor) of the flow battery. These two elements are present in ample quantity on Earth and after mixing, they create a liquid metal at room temperature. Theoretically, this liquid metal has at least 10 times the available energy per gram compared to other candidates.
The researchers used a ceramic membrane made of potassium and aluminum oxide to separate the negative and positive materials while allowing current to flow.
With these materials, the team was able to get more than double the maximum voltage of conventional flow batteries, thereby allowing storage of more amount of energy. The prototype was also found to remain stable for thousands of hours of operation.
The team has also tested four different liquids for the positive side of the battery.
The detailed findings of the research were published in Joule.