LiCo0.9M0.1PO4 (M=Co2+, Mg2+, Ca2+) compounds are synthesized by Pechini-assisted sol–gel process and after annealing at 300°C for 5min in air, then at 730°C for 12h in nitrogen (2-steps annealing process). The XRD-patterns reveal the presence of LiCoPO4 as major crystalline phase and of CoP2O7 (M=Co), of Co2P (M=Mg), of Co2P, Li3PO4, (Ca,Co)3(PO4)2 (M=Ca) as impurities. The morphological investigation shows a homogenous spongy-like structure for M=Co, and a more compact structure with spherical particles separated on the surface in Mg- and Ca-containing systems. In the voltammetric curves, a very good reversibility with mean peak maxima in the cathodic region of 4.4V for M=Co, 4.5V for M=Ca and 4.6V for M=Mg respectively are observed. The discharge specific capacities, at a discharge rate of C/10 and room temperature, were 60mAhg−1 for M=Co, 36mAhg−1 for M=Mg and 68mAhg−1 for M=Ca respectively. The electrochemical impedance spectroscopy data reveal a decrease of the electrical resistance and the improvement of the Li-ion conductivity after the addition of Ca and Mg-ions into the LiCoPO4 system.