Solid Sulphate Electrolytes The First Examples of a Strange Ion Transport Mechanism

Neutron and X-ray diffraction studies reveal that fcc Li//2SO//4, bcc LiNaSO//4, and bcc LiAgSO//4 are characterized by a strong rotational disorder of the sulfate ions which strongly enhances the mobility of the cations. Single crystal neutron scattering studies have been performed on fcc Li//2SO//4 and the quasielastic scattering supports the previous conclusions, and more detailed information should be obtinable by this technique. The elastic constants of fcc Li//2SO//4 have been determined by Brillouin scattering. The information obtained so far by Raman scattering concerning the motion of lithium ions in fcc Li//2SO//4 supports earlier conclusions from conductivity measurements.