Electrochemical corrosion drives dendrite growth at low stresses in solid-state batteries

A Nature study on LLZO-based solid electrolytes shows dendrites propagate at stresses far below the mechanical fracture threshold, with plating-induced stresses present during growth; as current density rises, dendrite velocity increases while the stress required for propagation decreases (up to 75% lower than under purely mechanical loading). Cryogenic STEM reveals electrochemically induced electrolyte decomposition and molar-volume changes, indicating an electrochemical embrittlement mechanism that could be mitigated by controlling the phase transitions accompanying instability.