A new combination of materials developed by Stanford researchers may aid in developing a rechargeable battery able to store the large amounts of renewable power created through wind or solar sources. With further development, the new technology could deliver energy to the electric grid quickly, cost effectively and at normal ambient temperatures.
The technology – a type of battery known as a flow battery – has long been considered as a likely candidate for storing intermittent renewable energy. However, until now the kinds of liquids that could produce the electrical current have either been limited by the amount of energy they could deliver or have required extremely high
temperatures or used very toxic or expensive chemicals.
Stanford assistant professor of materials science and engineering William Chueh, along with his PhD student Antonio Baclig and Jason Rugolo, now a technology prospector at Alphabet’s research subsidiary X Development, decided to try sodium and potassium, which when mixed form a liquid metal at room temperature, as the fluid for the electron donor – or negative – side of the battery. Theoretically, this liquid metal has at least 10 times the available energy per gram as other candidates for the negative-side fluid of a flow battery.
“A new battery technology has so many different performance metrics to meet: cost, efficiency, size, lifetime, safety, etc.,” said Baclig. “We think this sort of technology has the possibility, with more work, to meet them all, which is why we are excited about it.”
The team of Stanford PhD students, which in addition to Baclig includes Geoff McConohy and Andrey Poletayev, found that the ceramic membrane very selectively prevents sodium from migrating to the positive side of the cell – critical if the membrane is going to be successful. However, this type of membrane is most effective at temperatures higher than 200 degrees Celsius (392 F). In pursuit of a room-temperature battery, the group experimented with a thinner membrane. This boosted the device’s power output and showed that refining the membrane’s design is a promising path.