Designing TEM experiments with thin lamella all-solid-state cells in controlled atmosphere using electrochemical chips

While in situ techniques in transmission electron microscopy (TEM) field provide increasingly more useful and accurate data on various physical phenomena, electrochemical reactions occurring on interfaces in all-solid-state lithium-ion batteries (ASSLIB) still remain incompletely understood. High resolution and time-resolved TEM observations of interfaces stand as the pinnacle of battery research, but current most promising solid electrolyte materials exhibit major inconveniences for standard characterization protocols such as ambient air sensitivity. While several groups have developed methods to study lithium-ion cells in in situ TEM, mostly through thin lamella preparation, few seemed to have kept the sample in controlled atmosphere. Yet, this can stand as a critical criterion for maintaining material integrity during transfer and acquisition. In this work, we describe our attempt to lead operando-TEM characterization on a thin lamella all-solid-state lithium-ion cell by a new technique involving the use of a specific controlled-atmosphere sample holder and electrochemical chips including electron-transparent windows. Achievements, challenges and prospects of this method are discussed here.