Pressure effects on electrochemical and crack driving forces in aluminium-doped LLZO-based all-solid-state lithium metal batteries

This study employed a combination of computational models and experimental techniques to investigate the effects of stacking pressure on the mechanical deformation and electrochemical performance of All-Solid-State Li metal batteries (ASSLBs). The effects of the stacking pressure were studied in Al-doped LLZO-based electrolytes at the electrode/electrolyte interface and within the electrodes. Optical microscopy and digital imaging correlation (DIC) techniques were used to study the strain distributions induced in the Al-LLZO-based electrolyte at different stack pressures. The results show that minimal levels of stack pressure result in low strains within the electrolyte, whereas intermediate increasing pressures increase the interfacial contacts and electrochemical performance of the cells. However, higher stacking pressures result in higher induced levels of local stresses and strains, which are sufficient to cause cracking and degradation of the electrochemical performance. The implications of the results are discussed for the pressure-assisted manufacturing of all-solid-state lithium metal batteries.