Contributing to the slight information about the Cu-Li alloys that is nowadays in scientific literature, this work reports the evolution with the temperature of the Cu - 2,5 wt % Li alloy. This alloy is obtained as powder by an electrodeposition process from salts. Powder samples, room temperature compacted tablets and the copper cathodes used in the process are analyzed. The samples were annealed in the rank from 293 to 673 K by different times and then characterized by means of x-rays diffraction. The lithium content was determined by atomic absorption. The analysis of the results shows a decomposition of the alloy as the temperature increases, with a loss of lithium towards the surface of the samples, where this element easily reacts with the atmosphere forming soluble water compounds.