Lithium-ion conductivity in the novel La1/3−xLi3xNbO3 solid solution with perovskite-related structure

The stoichiometric range, crystal chemistry, ionic conductivity and electrochemical window of the La1/3−xLi3xNbO3 solid solution with a perovskite-related structure have been studied. The range of existence of the solid solution appears to be 0≤x≤0.06. These niobates have a basic diagonal unit cell a≈√2ap b√2ap c≈2ap. Ionic conductivity of the materials and its dependence with the composition and temperature have been examined. We have found that the highest conductivity value is 4.3×1O−5 S cm−1 at 300 K for x=0.04. The electrochemical window of the compounds has been investigated by potentiostatic discharge and charge. Electrochemical experiments show that the use of the materials as solid electrolytes in secondary batteries is limited down to 1.75 V using Li metal as anode.