Evaluating Interfacial Stability in Solid-State Pouch Cells via Ultrasonic Imaging

Abstract

Chemical/electrochemical stability at the interfaces greatly affects the performance of solid-state batteries (SSBs). However, the interfacial behavior in SSBs remains elusive due to the subsurface nature of interfaces and the lack of proper characterization methods. Herein, ultrasonic imaging technology is employed to non-destructively investigate the interfacial stability in solid-state pouch cells. Bene ting from the high sensitivity of ultrasound to the gas/vacuum, in-situ ultrasonic imaging can effectively probe the inner gas release and interfacial degradation in pouch cells during long-term cycling. The safety issue of SSBs is highlighted by the ammable gas release detected in ultrasonic images. And the increased interfacial resistance either from contact loss or passivation layer growth is well distinguished.The gradual oxidation and gassing at the cathode interface are tracked by ultrasonic imaging, which leads to the capacity fading of SSBs. The ultrasonic imaging technology is demonstrated to be a powerful tool to evaluate the interfacial stability in SSBs, which can guide the rational design of interfaces and enhance the performance of SSBs.

Silicon as Emerging Anode in Solid-State Batteries

“…96−98 Coating materials on the surface of silicon particles may suppress side reactions, but also alleviate the volume change of silicon anodes, which is worth further exploration in the future. 26,97 Obviously, silicon anodes may offer a new perspective for SSB, and first reports are promising. However, as summarized, a number of issues have to be solved, and we consider both the ionic/electronic transport in silicon anodes as well as their chemo-mechanics as the most pressing issues.…”

“…The chemical/electrochemical stability between silicon and sulfide SEs remain elusive, although it is generally acknowledged that sulfide SEs are not stable in contact with silicon at low potentials. The mechanisms of degradation of sulfide SEs at both NCM cathodes and the lithium anode have been successfully revealed using multiple characterization techniques, such as in situ XPS, ToF-SIMS, and DEMS. − Advanced imaging techniques have also been proven as useful for the failure analysis of silicon anodes in SSBs, such as ultrasonic imaging, operando transmission electron microscopy, and X-ray tomography. − Coating materials on the surface of silicon particles may suppress side reactions, but also alleviate the volume change of silicon anodes, which is worth further exploration in the future. , …”

Advances in Solid-State Batteries, a Virtual Issue, Part II

“…There are still many fundamentals of SSBs that need to be further understood, such as the critical current densities, solid-state lithiation reactions, and actual lithiation temperature, which requires the development of modeling, , imaging (i.e., cryogenic transmission electron microscopy, ultrasonic imaging, etc.) and operando characterization techniques (i.e., operando Kelvin probe force microscopy and neutron depth profiling, in situ MRI, etc.).…”

Strategies and characterization methods for achieving high performance PEO-based solid-state lithium-ion batteries

“…Huang et al introduced ultrasonic imaging techniques to study the gas release and interfacial instability in PEO-based SSEs. 92 Ultrasound attenuates significantly when it passes through gases or voids. When the lithium metal is in contact with the PEO/LLZTO composite electrolyte, the transmitted ultrasonic signal went through significant attenuation indicating the gas existence.…”