Electrochemical characteristics of aluminum sulfide for use in lithium secondary batteries

摘要

In our effect to develop a lithium secondary battery with high energy density, aluminum sulfide (Al_2S_3) was studied for use as an active material. The measured initial discharge capacity of Al_2S_3 was ca. 1170mAh g~(-1) at 100mAg~(-1). This corresponds to 62% of the theoretical capacity for the sulfide. Al_2S_3 exhibited poor capacity retention in the potential range between 0.01 V and 2.0 V, mainly due to the structural irreversibility of the charge process or Li extraction. XRD and Al and S K-XANES analyses indicated that the surface of Al_2S_3 reacts reversibly during charge and discharge processes, while the core of Al_2S_3 showed structural irreversibility because LiAl and Li_2S were formed from Al_2S_3 at the initial discharge and remained as they were afterward.