The State of Reliable Characterization and Testing of Solid-State Batteries

Solid-state batteries unlock possibilities for using energy-dense anodes such as lithium metal while addressing key degradation challenges. However, unresolved issues at the material and cell levels have hindered their commercialization, including variability in mechanical control and testing methodologies, a limited understanding of material behavior under operating conditions, and performance and design gaps between cells for benchtop testing and cells for advanced characterization. This perspective highlights the current state-of-the-art in testing and characterizing solid-state batteries, focusing on mechanical monitoring and controls, benchtop diagnosis and characterization techniques, and advanced operando synchrotron imaging. We emphasize the need for uniform experimental standards, scalable and practical battery cell designs to match commercial operating conditions, and integrated approaches to design advanced in situ and operando experiments to reflect realistic battery operating conditions.