We report on a density functional theory (DFT) calculation of the properties of LiMPO4, where M is either Fe, Mn or Co. The mixing between Fe and Mn in these structures is also examined. We have derived three relevant battery properties, namely average voltage, energy density and specific energy, as well as the lattice constants and ionic coordinates for each case examined. Our calculated values for these properties are in good agreement with recent experimental values, when available. Further insight is gained from the electronic density of states of the phases, through which conclusions about the physical properties of the various phases are made. (C) 2003 Elsevier B.V. All rights reserved.