Patent ID: 6872492

Claim:
A battery, comprising: a positive electrode comprising an electrode active material represented by the formula: A a M b (XY 4 ) c Z d , wherein: (a) A comprises Na, and 0<a≦9; (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; and (c) XY 4 is selected from the group consisting of X′O 4−x Y′ x , X′O 4−y Y′ 2y , X″S 4 , and mixtures thereof, where X′ is selected from the group consisting of P, As, Sb, Si, V, Ge, S, and mixtures thereof; X″ is selected from the group consisting of P, As, Sb, Si, V, Ge, S, and mixtures thereof; Y′ is selected from the group consisting of halogen, S, N, and mixtures thereof; 0≦x<3; 0<y≦2; and 0<c≦3; and (d) Z is selected from the group consisting of OH, a halogen, and mixtures thereof; and 0<d; wherein M, XY 4 , Z, a, b, c, d, x, and y are selected so as to maintain electroneutrality of the electrode active material; the battery further comprising a negative electrode; and an electrolyte.