The electrochemical behavior of the lithium / V2(SO4)3system has been studied with XRD observation of the intercalation/deintercalation induced structural changes. Experiments have been performed on the NASICON type rhombohedral form. The use of very slow staircase potentiodynamic cycling made able to show that the first reduction occurs in two steps very close in energy and that the system experiences an irreversible structural change if this reduction is driven to the second step, below 2.59V vs Li0-Li+. Then, after a specific first oxidation step at 2.8 V, the system can be cycled reversibly through two redox levels at 2.63 V and 2.59 V.