In this paper we report density-functional theory (DFT) calculations at various levels of accuracy to compare the electrochemical properties of several silicate compounds as possible cathode materials in Li-ion batteries. We have tested the already known olivine-like structure (LiMSiO4, M=Mn, Fe, Co, and Ni) and the more recently discovered tetrahedral Pmn21 Li2MSiO4 (M=Mn, Fe, Co, and Ni). Our calculations show the influence of exchange and correlation potentials used to compute the redox potentials, electronic band gaps and other properties of these materials. A detailed study of the multicomponent effect on those characteristics gives us useful insight about how to improve the electrochemical performance of the cathode and its efficiency in the Li-ion battery.