Electrochemical lithium insertion in Nb8-nW9+nO47 (1 <= n <= 6)

Electrochemical lithium insertion have been carried out in different compos tions within the solid solution with general formula Nb8-nW9+nO47 (1 less t han or equal to n less than or equal to 6). Through galvanostatic and poten tiostatic techniques we have detected that lithium insertion proceeds by at least two reduction step. These process seem are relationship with the mol ar ratio Nb/W. The maximum lithium content reached leads to a specific capa city of 170 Ah/kg. Nevertheless, due to irreversible structural transformat ions in the matrix-host such capacity was lost after the first cycle. The d etailed analysis about the insertion kinetic process and in situ X-ray diff raction experiments have been carried out in this work.