Alkali/Transition Metal Halo-And Hydroxy-Phosphates And Related Electrode Active Materials

An electrode active material represented by the general formula:

• AaMb(XY4)2Zd,
• wherein
• (a) A is selected from the group consisting of Li, Na, K, and mixtures thereof, and 0.1<a≦6;
• (b) M comprises one or more metals, comprising at least one metal which is capable of undergoing oxidation to a higher valence state, and 1≦b≦3;
• (c) XY4 is selected from the group consisting of X′O4-xY′x, X′O4-y Y′2y, X″S4, and mixtures thereof, where X′ is P, As, Sb, Si, Ge, S, and mixtures thereof, X″ is P, As, Sb, Si, Ge and mixtures thereof, Y′ is a halogen, 0≦x<3, and 0<y<4;
• and
• (d) Z is selected from the group consisting of a hydroxyl, a halogen, and mixtures thereof and 0<d≦6;
• and
• wherein A, M, X, Y, Z, a, b, d, x and y are selected so as to maintain electroneutrality of the electrode active material.