Argonne National Laboratory

Researchers have discovered a new class of battery electrode materials that will be essential to attaining safe and efficient lithium (Li) and sodium (Na) rechargeable energy storage systems for vehicle and large-scale electric utility use.

Selenium (Se) and mixed selenium-sulfur (Se_xS_y) make up the new class of promising cathode materials for Li- and Na-based rechargeable batteries. During lab tests, the technology was repeatedly cycled up to 100 times at 4.6 volts without failure, demonstrating the system's excellent cycle life.

The high densities and voltage output of Se and Se_xS_y also offer greater volumetric energy densities than sulfur (S)-based batteries, making possible the development of new energy storage systems that can enable electric vehicles and smart grids.

Se and Se_xS_y can also be cycled at room-temperature against Na compared to Na-S, which only operates at high temperatures. High temperatures decrease a battery's safety. Additionally, the new battery system offers a solution to the two major Li/S problems: sulfur dissolution and capacity fade.

The Advanced Photon Source was used to collect high energy X-ray scattering data from samples at various states of charge and discharge to gain insight into the structural mechanisms underlying the Li and Na insertion reaction.

The scientific paper by Argonne researchers Ali Abouimrane, Damien Dambournet, Karena W. Chapman, Peter J. Chupas, Wei Wang, and Khalil Amine, titled "A New Class of Lithium and Sodium Rechargeable Batteries Based on Selenium and Selenium-Sulfur as a Positive Electrode," was published in the Journal of the American Chemical Society, 2012, 134 (10), pp 4505–4508.