Speaker
Description
Solid-state batteries have attracted significant attention as a possible next-generation electrochemical energy storage, with the high energy density of alkali-metal anodes and improved safety of solid electrolytes over conventional liquid electrolytes. However, the advancement of this technology is limited by complex electro-chemo-mechanical evolution at the interface between the alkali-metal electrode and the solid electrolyte. A deeper understanding of these processes is crucial in order to stabilize the interface and improve the performance of solid-state batteries.
In this work we have studied the interface evolution in lithium and sodium solid-state batteries with sulfide solid electrolytes. The interface between the solid electrolyte and alkali-metal electrode was imaged in-situ using X-ray nanotomography. With this approach, we have been able to monitor multiple aspects of the electro-chemo-mechanical mechanisms. Lithium metal deposition was tracked, where we could observe the growth of lithium metal around the particles in the solid electrolyte, as well as how lithium grows into the cracks in the electrolyte. Interphase growth as a result of chemical degradation between sodium metal and solid electrolyte was tracked over time, where a heterogeneous two-phase morphology could be seen to evolve. Finally, the formation and propagation of cracks was observed, as well as their effect on the metal plating as mentioned above. These results give insight into the dynamics of the alkali-metal / solid electrolyte interface, highlighting how (electro)chemical and mechanical instabilities affect the performance of solid-state batteries.