New battery could store hours’ worth of energy on the grid

MIT Technology Review : Sun Catalytix, a startup based in Cambridge, Massachusetts, is developing a new type of battery that can store large amounts of electrical energy during periods of low consumer demand. Such batteries, known as flow batteries, work by forcing an electrolyte through a membrane. Driven in one direction, the flow creates a current. Driven in the other, the flow stores charge. Sun Catalytix’s flow battery works in the same way but uses a safer, aqueous electrolyte instead of a potentially hazardous strong acid. Another difference: The metal ions that are dissolved in the electrolyte are chemically attached to molecules, which extends the lifetime of the battery. Having developed a 50-cell prototype, Sun Catalytix predicts that a full-scale system, which it expects to have ready in 2-3 years’ time, will be twice as cost-effective at storing electricity as the sodium-sulfur flow batteries currently in use.