This illustration shows the crystal structure of the eldfellite cathode developed for sodium-ion batteries. Illustration: Cockrell School of Engineering.Led by the inventor of the lithium-ion battery, a team of researchers in the Cockrell School of Engineering at the University of Texas at Austin has identified a new safe and sustainable cathode material for low-cost sodium-ion batteries.
Over the past five years, sodium-ion batteries have emerged as a promising new type of rechargeable battery, and an alternative to the currently ubiquitous lithium-ion battery. This is because sodium is abundant and inexpensive, whereas lithium-ion batteries are limited by high production costs and the availability of lithium.
Sodium-ion batteries could one day be used for storing wind and solar energy and powering electric vehicles, but first researchers need to improve their performance and safety. To that end, John Goodenough, the inventor of the lithium-ion battery, and his team have identified a new cathode material for sodium-ion batteries made of the nontoxic and inexpensive mineral eldfellite. The researchers report their findings in Energy & Environmental Science.
"At the core of this discovery is a basic structure for the material that we hope will encourage researchers to come up with better materials for the further development of sodium-ion batteries," said Preetam Singh, a postdoctoral fellow and researcher in Goodenough's lab.
Sodium-ion batteries work just like lithium-ion batteries. During discharge, sodium ions travel from the anode to the cathode, while electrons pass to the cathode through an external circuit. The electrons can then be used to perform electrical work.
Although sodium-ion batteries hold tremendous potential, there are several obstacles to advancing the technology, including issues relating to their performance, weight and instability. The team's proposed cathode material addresses the instability issue. It consists of fixed sodium and iron layers that allow sodium ions to be inserted and removed while retaining the integrity of the cathode structure.
One challenge the team is currently working on is that their cathode would produce a battery that is less energy dense than today's lithium-ion batteries. The new cathode can currently only achieve a specific capacity (the amount of charge it can accommodate per gram of material) that is two-thirds that of a lithium-ion battery.
"There are many more possibilities for this material, and we plan to continue our research," Singh said. "We believe our cathode material provides a good baseline structure for the development of new materials that could eventually make the sodium-ion battery a commercial reality."
This story is adapted from material from the University of Texas at Austin, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.