Abstract
A Solid-state battery uses solid electrodes and Solid Electrolytes (SEs) instead of liquid electrolytes. One of the key challenges for decades has been the inability to use Li metal as an anode for liquid electrolyte-based batteries for safety reasons. Li has the highest theoretical specific capacity and lowest reduction potential. Thus using Li as an anode ensures maximizing the energy density. With advances in the SEs exceeding the ionic conductivity of commercial liquid electrolytes, there’s new emerging hope to finally use Li metal anodes. Thus the key motive for implementing SEs is to ensure safety and use the "Holy grail" Li metal anode. However, the road to the success of Li-solid state batteries is full of "solid-solid interfacial challenges". The goal of this PhD work is to contribute to the existing fundamental understanding of interfacial challenges using the in-house developed cell to perform in situ/operando scanning electron microscopy (SEM). Among different techniques being used to understand the fundamentals of battery challenges, scanning electron microscopy (SEM) offers a good compromise in terms of size and resolution of observation with the possibility to perform studies with a good spatial resolution. By combining the imaging with chemical analyses by X-ray energy dispersive spectroscopy (EDX), a complete survey of morphological and chemical modification is possible. The understanding from in situ/ SEM has been coupled with Electrochemical Impedance Spectroscopy (EIS) to gain further insights from the electrochemical point of view