Rice University researchers develop flexible MOF for solid-state batteries

Researchers at Rice University have developed a flexible metal-organic framework (MOF) material called ZnBTCA that could improve the performance of solid-state batteries. Unlike traditional MOFs that use rigid aromatic linkers, ZnBTCA utilizes flexible aliphatic linkers, allowing the material to be softer and more mechanically adaptable while maintaining a negatively charged structure that facilitates the movement of positively charged lithium ions.

Solid-state batteries aim to replace flammable liquid electrolytes with solid materials to increase safety and energy density. However, rigid solid electrolytes often struggle to maintain consistent contact with electrode surfaces. The ZnBTCA framework addresses this by combining selective ion transport with mechanical flexibility.

In testing, researchers exchanged sodium ions for lithium ions within the material, resulting in lithium accounting for approximately 95% of the mobile charge-balancing ions. When incorporated into a solid electrolyte membrane between lithium-metal electrodes, the cells operated stably for nearly 300 hours under increasing current without evidence of short-circuiting. The material is also noted for using relatively abundant and low-cost components, such as zinc.