Electrode active materials comprising two or more groups of particles having differing chemical compositions, wherein each group of particles comprises a material selected from: (a) materials of the formula A¹_aM¹_b(XY₄)_cZ_d; and (b) materials of the formula A²_eM²_fO_g; and wherein (i) A¹, A², and A³ are Li, Na, or K; (ii) M¹ and M³ comprise a transition metal; (iv) XY₄ a phosphate or similar moiety; and (v) Z is OH, or halogen. In a preferred embodiment, A²_eM³_fO_g is A³_hMn_iO₄ having an inner and an outer region, wherein the inner region comprises a cubic spinel manganese oxide, and the outer region comprises a manganese oxide enriched in Mn⁺⁴ relative to the inner region. In a preferred embodiment, the compositions also comprise a basic compound.