Understanding ion and electron transport in composite cathodes.

Thilina Nadeemali DIkella Dikella Gamaralalage, Yan-Yan Hu

Florida state university

Understanding ion and electron transport in composite cathodes.

The performance of solid-state battery cells primarily hinges on the transfer kinetics of ions and electrons within the electrode materials. Sluggish ion movement within catholytes of all-solid-state batteries (ASSBs) poses a significant hurdle to advancing high-power battery technology. The connectivity of ionic and electronic pathways predominantly governs the ion transport kinetics in battery materials. While liquid batteries benefit from favorable ion and electron percolation due to their excellent wettability, the rigid nature of solid electrolyte particles often limits effective contact between solid electrolyte (SE) and cathode active materials (CAMs), leading to insufficient Li-ion conduction within the cathode. To address this challenge, integrating SE within the cathode to form a catholyte represents a widely adopted solution for establishing robust Li-ion percolation. In solid-state batteries, cathode composites usually adhere to a standard ratio of solid electrolyte to active material. Nevertheless, adjusting this ratio becomes necessary with every alteration in material composition to ensure superior transport properties and maintain well-balanced and optimal partial conductivities. This research aims to investigate the Li ion and electron transport dynamics within catholytes comprised of halide solid electrolytes (Li₃YBr₆/Li₃YCl₆) and carbon-coated LiFePO4, focusing on their effective conductivities. We used the direct current polarization technique to discern the effective conductivities of the fabricated catholytes. This research provides novel insights into electrode design, aiming to advance the development of ASSBs.