Electrochemical Properties of All-solid-state Lithium Batteries with Amorphous FeSx-based Composite Positive Electrodes Prepared via Mechanochemistry

Iron sulfide (FeSx) composite positive electrodes were prepared mechanochemistry and applied to all-solid-state lithium cells. The prepared composites, consisting of Fe, S, Li3PS4 solid electrolyte (SE), and vapor-growth carbon fiber (VGCF), were in amorphous state after ball milling for 10 h. An all-solid-state cell with an amorphous Fe-S-SE-VGCF composite as the positive electrode exhibits a high reversible capacity of 420mAh per total weight of the composite electrode at a current density of 0.13mAcm(-2) at 25 degrees C. The cell exhibited a capacity retention of 88% after 200 cycles at a current density of 0.64mAcm(-2) at 25 degrees C. The all-solid-state cell using the Fe-S-SE-VGCF composite at a current density of 0.13mAcm(-2) at 100 degrees C exhibited a higher reversible capacity of 550mAhg(-1). The Fe-S-SE-VGCF composite is thus a promising positive electrode material, with high capacity and good cycle performance for all-solid-state lithium secondary batteries. (c) The Electrochemical Society of Japan, All rights reserved.