Behavior of some potassium tungstates in the course of electrochemical lithium insertion

Abstract

Electrochemical lithium insertion has been studied in K 2WO 4, K 2W 3O 10 and K 2W 4O 13 through galvanostatic intermittent titration technique. We have monitored structural changes in the host matrix as lithium insertion proceeds through in situ X-ray diffraction experiments. In particular, K 2WO 4 showed to be unable to insert lithium in appreciable amounts. The maximum amount of lithium inserted in each oxide leads to specific capacities of 18 Ah/kg for K 2WO 4, 220 Ah/kg for K 2W 3O 10 and 265 Ah/kg for K 2W 4O 13. Nevertheless, due to irreversible structural transformations in the host matrix, such capacities were dramatically lost after the first cycle.