The present invention includes substantially single-phase lithium metal oxide compounds having hexagonal layered crystal structures that are substantially free of localized cubic spinel-like structural phases. The lithium metal oxides of the invention have the formula Li.sub..alpha.M.sub..beta.A.sub..gamma.O.sub.2, wherein M is one or more transition metals, A is one or more dopants having an average oxidation state N such that +2.5.ltoreq.N.ltoreq.+3.5, 0.90.ltoreq..alpha..ltoreq.1.10, and .beta.+.gamma.=1. The present invention also includes dilithiated forms of these compounds, lithium and lithium-ion secondary batteries using these compounds as positive electrode materials, and methods of preparing these compounds.