Gd-doped ceria (Ce0.80Gd0.20O1.90) obtained by several nanopowder synthesis processes are compared structurally, morphologically and electrochemically. The powders have been sintered into pellets and investigated by ac-impedance measurements. The electrochemical properties of the electrolytes have been correlated to the structural morphology of the sintered pellets. When the intergrain region exhibits an elevated interdiffusion, the observation of the grain boundaries becomes difficult while the electrochemical properties are improved. Acrylamide polymerization and oxalic co-precipitation techniques showed the best properties.