An investigation into compressive deformation and failure mechanisms in a novel Li-ion solid-state electrolyte

Solid-state batteries are generally considered to be safer than their liquid-state counterparts due to their decreased potential for fire or short circuiting. The fabrication of solid-state batteries relies on the application of stack crimping pressure that increases the interfacial surface contacts between electrolytes and the electrodes. However, excessive compressive crimping stresses (that occur in cell assembly) can give rise to cracking phenomena that can degrade battery performance and lead to thermal runaway or failure. It is, therefore, important to develop an understanding of failure mechanisms in solid-state Li-ion electrolytes. In this paper, we use a combination of in-situ optical microscopy and Digital Imaging Correlation (strain mapping) techniques to study compressive deformation and cracking phenomena in a novel solid-state Li-ion electrolyte. The stress states associated with the different stages of compressive deformation are also presented along with those due to charge–discharge cycles. The implications of the results are discussed for the material design of robust solid-state Li ion batteries.