Researchers from Washington State University (WSU) and Pacific Northwest National Laboratory (PNNL) have created a sodium-ion battery that works as well as some lithium-ion batteries, meaning that a cheaper alternative is now a reality. The team of scientists report their sodium-ion battery can deliver a similar amount of energy as lithium-ion batteries and they’re able to retain more than 80% of their charge after 1,000 cycles. The results of the study are published in the journal, ACS Energy Letters.
According to Dr. Imre Gyuk, director of Energy Storage for the Department of Energy's Office of Electricity, “This is a major development for sodium-ion batteries. There is great interest around the potential for replacing Li-ion batteries with Na-ion in many applications."
Lithium-ion batteries are used in a wide range of applications, including cell phones, laptops, and electric cars, but the materials used to make them are rare, expensive, and need to be imported into the United States. As the demand for these devices increases, these materials will become increasingly hard to acquire and more expensive as well. By contrast, sodium-ion batteries are made from cheap, readily available sodium, which is available from the ocean or the earth’s crust. While the cost is attractive, sodium-ion batteries don’t hold nearly as much energy as lithium-ion batteries, until now that is.
"The key challenge is for the battery to have both high energy density and a good cycle life," said Junhua Song, lead author on the paper and a WSU Ph.D. graduate who is now at Lawrence Berkeley National Laboratory. The lead researcher, Yuehe Lin, a professor in the School of Mechanical and Materials Engineering at WSU says, "Our research revealed the essential correlation between cathode structure evolution and surface interaction with the electrolyte. These are the best results ever reported for a sodium-ion battery with a layered cathode, showing that this is a viable technology that can be comparable to lithium-ion batteries."
"This work paves the way toward practical sodium-ion batteries, and the fundamental insights we gained about the cathode-electrolyte interaction shed light on how we might develop future cobalt-free or low cobalt cathode materials in sodium-ion batteries as well as in other types of battery chemistries," Song said. "If we can find viable alternatives to both lithium and cobalt, the sodium-ion battery could truly be competitive with lithium-ion batteries.