A preliminary investigation of fracture toughness of Li7La3Zr2O12 and its comparison to other solid Li-ionconductors

Abstract This is the first report of fracture toughness analysis of a new ceramic electrolyte (Li 7 La 3 Zr 2 O 12 ). The fracture toughness was measured using an indentation technique and subsurface crack propagation was analyzed using a novel focused ion beam/scanning electron microscope (FIB–SEM) technique. The fracture toughness of polycrystalline Li 7 La 3 Zr 2 O 12 was between 0.86–1.63 MPa√m. FIB–SEM analysis of the indentation cracks suggested that both half-penny and Palmquist cracks were present. The fracture toughness of Li 7 La 3 Zr 2 O 12 is comparable to other state of the art ceramic electrolytes such as Li 0.33 La 0.57 TiO 3 and Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 .