The use of nanometric particles of the LiMn2O4 spinel as a cathode in rechargeable lithium ion batteries has been a widely accepted strategy to build high power devices. Several studies show that by phosphate doping (PO43-) and using nanometric particles it is possible to achieve excellent electrochemical stability and charge transport. Despite the upward trend in specialized literature in applying phosphate doping in the LiMn2O4, a study concerning the structural position of this polyanion in the spinel crystalline cell as well as the mechanism through the electrochemical properties are improved have not been yet proposed. To clarify the topic above mentioned doped and undoped materials were synthesized by a citrate rout and characterized by SEM-EDS, STEM, HRTEM, XRD, and electrochemical testing in aqueous electrolyte. The analysis of STEM images and the structural refinement using the Rietveld's method allowed to elucidate the position of the phosphate group in the LiMn2O4 nanostructure. Electrochemical tests showed the improvement of the electrochemical properties (stability of the discharge capacity) of the doped nanoparticles and the inhibition of undesired segregated phases during cycling. As a conclusion it can be said that due to the position of the phosphate ion substituting the LiO43- tetrahedral, symmetry and energy constraints inhibit phase segregation during charge-discharge processes, stabilizing the cubic spinel structure.