New sodium batteries: comparable to lithium-ion batteries
Background of lithium battery
Lithium-ion batteries are ubiquitous and are used in everything from mobile phones and laptops to electric cars. But they are made of materials such as cobalt and lithium, which are scarce, expensive and mostly found outside the United States. As demand for electric cars and power storage grows, these materials will become increasingly difficult to obtain and potentially more expensive. Lithium-based batteries will also have problems meeting the huge increase in demand for energy storage on the grid. On the other hand, sodium-ion batteries, made of cheap, abundant and sustainable sodium from the earth's oceans or crust, are an excellent candidate for large-scale energy storage. Unfortunately, they don't store as much energy as lithium-ion batteries. They also struggle to charge as effectively as energy storage requires. A key problem for some of the most promising cathode materials is that an inactive sodium crystal accumulates on the surface of the cathode, blocking the flow of sodium ions and causing the battery to fail.
Technology and Innovation
Recently, the Washington state university (WSU) and the Pacific northwest national laboratory (PNNL) the researchers created a sodium ion batteries, its capacity and can work with some commercial lithium ion battery chemicals, is expected to become a rich and cheap material made of practical battery technology. This is one of the best sodium-ion battery results to date, the team reports. It can provide a capacity similar to that of some lithium-ion batteries, and it can be successfully charged and still maintain more than 80 percent of its power after 1,000 cycles. "The key challenge for batteries is to have high energy density and good cycle life," said Junhua Song, a doctoral student at Washington State University who now works at Lawrence Berkeley National Laboratory. As part of this work, the team created a layered metal oxide cathode and a liquid electrolyte that contains extra sodium ions to create a saltier soup that interacts better with their cathode. Their cathode design and electrolyte system allow sodium ions to continue to move, preventing the accumulation of inactive surface crystals and allowing unhindered power generation. The researchers are now working to better understand the important interaction between their electrolytes and the cathode, so they can improve battery design with different materials. They also hope to design a battery that does not use cobalt, another relatively expensive rare metal.
The value of a sodium ion battery
"This is a major advance in the field of sodium ion batteries," said Dr. Imre Gyuk, director of energy Storage research at the U.S. Department of Energy's Office of Electric Power, which supported the work at THE Pacific Northwest National Laboratory. The potential of sodium batteries to replace lithium-ion batteries in many applications is of great interest." "This work paves the way for practical sodium-ion batteries," Song said. "The basic insights we have gained about cathode-electrolyte interactions provide implications for the future development of cobalt-free or low-cobalt cathode materials in sodium-ion batteries and other types of battery chemicals. If we can find a viable alternative to lithium and cobalt, sodium batteries could really compete with lithium-ion batteries. And it's a game changer."
