Effect of microcracking on ionic conductivity in LATP

► Microcracking leads to high grain boundary impedance in LATP. ► Optimum total ionic conductivity of 0.7 mS cm−1 and activation energy of ∼0.35 eV. ► d.c. conductivity in aqueous LiOH measured as 1.6 mS cm−1 at 50 °C. ► Biaxial membrane strength measured as 123 MPa with 1.1 MPa√m fracture toughness.