Operando Spatial and Temporal Tracking of Axial Stresses and Interfaces in Solid‐state Batteries

Abstract

AbstractSolid‐state batteries have the potential to replace the current generation of liquid electrolyte batteries. However, the major limitation resulting from their solid‐state architecture is the gradual loss of ionic conductivity due to the loss of physical contact between the individual battery components during charging/discharging. This is mainly due to mechanical stresses caused by volume changes in the cathode and anode during lithiation and delithiation. To date, limited research has been devoted to understanding the spatio‐temporal distribution of stresses during battery operation. Here, operando scanning high‐energy X‐ray diffraction to quantify cross‐sectional axial stresses with a spatial resolution of 10 µm is used. It is shown how a non‐monotonous stress distribution evolves over time during the cycling of the solid‐state battery. In addition, degradation of the solid‐state electrolyte in the vicinity of the lithium anode is observed and tracked periodic changes in the unit cell volume in the cathode. The presented methodology of tracking the chemo‐mechanically induced stresses and interface morphology in real time in correlation with other battery parameters is believed, can provide a valuable platform for the future optimization of solid‐state batteries.