Sodium iron (II) phosphate/iron (III) phosphate mixtures with different Fe(II)/Fe(III) ratio were synthesized. X-ray diffraction, scanning electron micrographs, and thermal analysis were employed to characterize the samples. The electrochemical properties of electrodes prepared by using the samples as the active material were evaluated in lithium cells. One of the samples was electrochemical tested in sodium cells. The cell cyclability was evaluated as a function of the discharge rate. The values of capacity and voltage were employed for the calculation of the specific discharge energy and power. © 2015 IEEE.