A team of researchers in the Cockrell School of Engineering at The University of Texas, led by Professor John Goodenough, the inventor of the lithium-ion battery, has identified a safe, nontoxic, inexpensive and sustainable cathode material for low-cost Sodium-ion batteries, called Eldfellite.

Sodium-ion batteries are emerging as a promising rechargeable battery type and an alternative to Lithium-ion batteries because Sodium is abundant and inexpensive. In contrast, lithium-ion batteries are limited by high production costs and availability of lithium.

"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.

Although sodium-ion batteries have potential, there are obstacles to advancing the technology including issues related to performance, weight and instability of materials. The team’s proposed cathode material addresses instability. Its structure consists of fixed sodium and Iron layers that allow for sodium to be inserted and removed while retaining the integrity of the structure.

One challenge the team is currently working through is that their cathode would result in a battery that is less energy dense than today's sithium-ion batteries, achieving a specific capacity two-thirds of that of a sithium-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."