PHASE TRANSITIONS AND IONIC CONDUCTIVITY OF THE LITHIUM SULPHATE-LITHIUM PHOSPHATE SYSTEM
Abstract The phase diagram of the Li2SO4Li3PO4 binary system has been investigated using DTA, DSC, X-ray diffraction and ionic conductivity measurements. The low temperature limit of the solid solubility of the high temperature phase of Li2SO4 is an eutectoid point at 561°C and about 1 mol% Li3PO4. At 400°C the ionic conductivity in the two-phase region has a maximum of 1.5 × 10 −3 (Ω cm) −1 for 50 mol% Li3PO4 and an activation energy of 0.8 eV.