1. An electrode for a battery comprising:a nitride- or oxide-modified composition having the following formula:M1-zM?zOaF3-xNy,wherein:0
?3?x<0 or 0
M is selected from the group consisting of: Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Bi; and
M? is selected from the group consisting of: Na, Mg, Al, P, K, Ca, Sc, Cr, Fe, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sb, Te, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, and Bi.