Patent ID: 7008566

Claim:
A compound represented by the general nominal formula: A a M b X c O (3c+1) , wherein: (a) A is at least one alkali metal, and 0<a≦6; (b) M=M 1 d M 2 c M 3 f , wherein: (i) M 1 is at least one redox active element; (ii) M 2 is at least one 2+ oxidation state non-redox active element; (iii) M 3 is at least one 3+ oxidation state non-redox active element; and (iv) d, e and f>0; (d+e+f)=b; and 1≦b≦4; (c) X is selected from the group consisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof; and (d) 2≦c≦5; wherein A, M 1 , M 2 , M 3 , X, a, c, d, e, and f are selected so as to maintain electroneutrality of the compound.