Structural and Electrochemical Properties of ω-Li[sub x]V[sub 2]O[sub 5] (0.4≤x≤3) as Rechargeable Cathodic Material for Lithium Batteries

The phase has been investigated as rechargeable cathodic material for lithium batteries. The interest in using the ω phase as rechargeable electrode consists in the stability of its tetragonal structure as the Li insertion-extraction proceeds. Lithium ions are found to be responsible for the ordering of the structure. AC impedance measurements have shown important kinetic limitations appear in the Li composition range hindering the use of high current densities. However, at C/20 rate a remarkable and stable specific capacity of 310 mAh g −1 is obtained over 30 cycles. Its cycling behavior in the 3.8/1.5 V voltage window has been shown to strongly depend on the C rate and temperature. At a higher rate (C/5), the capacity decline observed as galvanostatic cycling proceeds has been found to originate from a significant dissolution process of the vanadium oxide, leading to the presence of and species in electrolyte.