Composite electrolytes were prepared from Li3P and LiCl by solid-state reaction. These substances were thermodynamically stable in contact with a Li electrode and had ionic conductivities that were appreciably higher than those of other known Li-ion conductors. The structures of the composites were then analyzed by using X-ray diffraction techniques. Thermal analysis of the composites revealed only a narrow range of miscibility between LiCl and Li3P. The phase diagram of this system was determined, and the formation of a simple eutectic at 9Li3P+LiCl was observed. The ionic conductivity of various compositions was measured between room temperature and 500C, and a low activation energy for Li transport was usually found.

G.A.Nazri, R.A.Conell, C.Julien: Solid State Ionics, 1996, 86-88[1], 99-105