Electrochemical lithium insertion in Nb8−xW9+xO47 (1≤x≤6)

Electrochemical lithium insertion have been carried out in different compositions within the solid solution Nb8−xW9+xO47 (1≤x≤6). Through galvanostatic and potentiostatic techniques, we have detected that lithium insertion proceeds by at least two reduction steps. These processes seem to be related to the molar ratio Nb/W. The maximum lithium content reached during the discharge process leads to a specific capacity of 170 Ah/kg. Nevertheless, due to irreversible structural transformations in the matrix-host, such capacity is lost after the first cycle. A detailed analysis about the insertion kinetic process will be discussed in this work.