Structural and Elemental Analysis of Sulfide-Based All-Solid-State Batteries via Advanced Microscopy and 3-D Tomography Techniques

摘要

The all-solid-state lithium batteries (ASSLBs) have drawn increasing interests and demands as the next-generation rechargeable batteries for electric vehicles and energy storage devices since they have much more potentials (e.g., higher safety, reliability, power density, and design flexibility) than conventional lithium batteries. In the last 30 years, extensive studies on all-solid-state batteries have been globally implemented to solve the current raising issues of ASSLBs, such as low lithium-ion conductivity, structural instability, and high resistance of electrode/electrolyte interface. In this process, sulfide-based ASSLBs are exhibiting the best performance approaching to the commercialization stage with various material advantages (e.g., excellent lithium-ion conductivity, room-temperature formability, and so on). Despite the comprehensive studies to develop high-performance sulfide-based ASSLBs, the fundamental understanding of crystallographic and elemental structure in sulfide-based ASSLBs through the 2-D microscopic and 3-D tomographic analysis has been lacking. Here we present the recent advances of structural and elemental analysis in sulfide-based ASSLBs using vacuum-transferred transmission electron microscopy (TEM) and 3-D tomography techniques. According to the high-speed energy dispersive X-ray spectroscopy and selected area diffraction analysis implemented in TEM, we verified the crystallographic results of bulk XRD analysis, and the microscopic elemental distribution of a composite cathode structure were successfully analyzed. Employing the atom probe tomographic technique, in addition, we properly reconstructed the cathode structure, and unveiled the 3-D distribution of each element (including lithium-ion) in the all-solid-state composite cathode. We believe these research activities lead to the promising technological advances and provide new guidelines in developing the sulfide-based ASSLBs for the next-generation rechargeable batteries.