Preparation of novel electrode materials based on lithium niobium sulfides

Abstract

Novel lithium niobium sulfide electrode materials, xLi2S·NbS2·(2-x)S (x = 1/2-2), were mechanochemically synthesized using Li2S, NbS2, and S8 as starting materials, and their electrochemical performance was investigated. The electrodes with x = 1/2 were in amorphous phase, while those with x = 1 and 3/2 are assigned as cubic phase. Cells prepared with these electrodes charge and discharge reversibly, with a capacity of ca. 400 mAh g-1. Within the wide operational voltage range 1.0-3.0V, Li3NbS4 charges and discharges with ca. 4.5-electron processes between Li0.4NbS4 and Li4.9NbS4. Li3NbS4 discharges even at a high current density of 2000 mA g-1 at 30°C.