The mechanism of lithium-metal penetration into solid-state electrolytes has been an important topic of scientific research since the seminal work of Monroe and Newman . They predicted that solid-state electrolytes with a shear modulus >8 GPa would suppress lithium metal intrusion due to the dependence of the electrochemical potential of lithium on stress . However, one of the most studied oxide solid electrolytes, Li7La3Zr2O12 (LLZO, which is usually doped with Al, Ta, or Ga), has a shear modulus of ~60 GPa but still exhibits intrusion growth at current densities well below 1 mA cm -2 (averaged across the electrode) , which is even lower than the threshold current density for liquid electrolytes. Recent theoretical studies resolve this contradiction by suggesting that the morphological instability of ceramic solid electrolytes is due to the low partial molar volume of lithium ions in the electrolyte . Nonetheless, theoretical models based on bulk and homogenous material properties do not explain the wide variation of current densities at failure shown in the literature . For example, while many authors report intrusions at current densities lower than 1 mA cm -2 , others report ~10 mA cm -2 with electrolyte surface treatment , and some report over 100 mA cm -2 without intrusion for lithium microelectrodes. This wide range of current densities at failure suggests an incomplete understanding of intrusion growth in LLZO.