A team led by engineers from the University of California, San Diego has introduced a new approach to designing metal alloy negative electrodes that could provide important advances in solid-state battery technology for electric vehicles and other high-performance energy storage applications.
The research group focused on the negative electrodes of lithium-aluminum alloys and investigated how lithium ions travel through different phases of the material: a lithium-rich beta phase and a lithium-poor alpha phase. By precisely adjusting the lithium-aluminum ratio, the researchers were able to significantly increase the share of the beta phase in their test materials.
The team found that a higher concentration of the beta phase improved lithium ion transport, with diffusion rates in the beta phase being up to ten billion times faster than those observed in the alpha phase. This resulted in electrode structures that were both denser and more stable, while creating more effective routes for lithium movement between the electrode and the solid electrolyte.
Solid-state batteries assembled with beta-phase enriched lithium-aluminum alloy electrodes exhibited high charge and discharge rates, maintaining stable capacity for more than 2,000 charging cycles in laboratory tests. These results indicate the potential for longer battery life and faster charging in future battery-powered devices and vehicles.
This study marks the first time that a direct relationship has been established between beta phase distribution and lithium diffusion within lithium-aluminum alloys. According to the research group, the findings provide guidance for the development of next-generation alloy-based battery electrodes with higher energy density, faster charging performance and improved reliability.
Research report:Lithium diffusion-controlled Li-Al alloy negative electrode for a fully solid-state battery
