All-Solid-State Batteries: Materials, Characterization and Manufacturing

All-solid-state batteries (ASSBs) hold great promise for revolutionizing electric vehicles by overcoming the safety and energy density limits of conventional lithium-ion batteries. Despite remarkable progress, significant challenges remain in both the fundamental understanding and scalable manufacturing of ASSBs. The performance of ASSBs critically depends on the quality of the electrode–solid electrolyte interface; however, its dynamic evolution during operation remains poorly understood due to limited operando characterization tools. I will first present our operando scanning electron microscopy studies conducted under realistic operating conditions, which directly visualize crack initiation and propagation within composite cathodes and void formation at the Li–electrolyte interface. Next, I will introduce a strategy to mitigate the need for high external pressure by employing low-hardness, creep-type electrodes that can accommodate microstructural changes during operation. Finally, I will highlight recent progress in solid-state battery manufacturing, emphasizing the importance of understanding lithium transport mechanisms in percolating mixed ionic–electronic conductor interlayers for high-performance ASSBs.