As reported initially by The Nikkei, the new sodium-ion battery is the size of a coin and functions at room temperature. Its sodium-based chemical compound acts as the positive electrode for the battery. If sodium-ion batteries make it to the market, they could be much cheaper than li-ion batteries, since sodium is abundant in seawater, and lithium is still relatively expensive. Also, Toyota is concerned electric vehicles won't become popular until they can go 500 to 1,000 kilometers on a charge. The company will continue its research to see if this is possible. If so, sodium-ion technology could be put into commercial use by 2020.
That's the tale, anyway.
The way this story developed legs, according to Toyota public affairs manager Cindy Knight, is that some Toyota engineers gave a highly technical paper at a battery conference last month. Following their talk, "they spoke with a reporter from Nikkei, who apparently misunderstood that they were talking about eventualities, and ended up exaggerating the capabilities," Knight said. "In fact [sodium-ion is] nowhere near production, just basic materials research they were presenting on. So yes, it's one of many chemistries we are exploring."
Sumitomo Chemical and Sumitomo Electric also have confidence in sodium. They're both testing out sodium-ion prototypes though they may not have direct competition with what Toyota is producing. Sumitomo Chemical's sodium battery storage capacity is around 90 percent that of comparable li-ion batteries, and Sumitomo Electric's battery could be utilized as a backup power source.
As for potential direct competition, there is a company that's working on making lithium ion batteries from brine in seawater. Simbol Materials, based on Pleasanton, CA, is setting up a plant to extract lithium from salty water, but that method is still in the testing phase. Simbol is developing a li-ion battery from brine that would be cheaper than what's typically available on the market.