Crystalline Structure and Electroconductivity of Solid Electrolytes Li3.75Ge0.75V0.25O4 and Li3.70Ge0.85W0.15O4

Crystalline structure of low- and high-temperature modifications of solid lithium-conducting electrolytes Li_3.75Ge_0.75V_0.25O₄ and Li_3.70Ge_0.85W_0.15O₄ are studied by powder neutron diffraction analysis with use made of Rietveld full-profile analysis. The structure of either composition is derivative from -Li₃PO₄. The high conductivity of the electrolytes is connected with the presence of interstitial lithium cations, whose positions are occupied but partially. Phase transitions in the electrolytes consist of the leveling of the occupation degrees of these positions and make practically no impact on the rigid cage of the lattice.