Discharge mechanism of MoS2 for sodium ion battery: Electrochemical measurements and characterization

New emerging large scale battery market has demanded low cost and high power or energy density materials. Sodium (Na) is a promising candidate for an anode material because of its low cost and natural abundance. Also molybdenum disulfide (MoS2) is an attractive cathode material with layered structure. In this study a Na/MoS2 cell was assembled so as to evaluate its electrochemical properties as a rechargeable battery. In the first discharge Na/MoS2 cell showed two characteristic plateaus at 0.93 V and 0.8 V. Galvanostatic charge/discharge cycle was carried out in different voltage ranges according to the discharge depths (0.85 V and 0.4 V). The electrochemical behaviors of Na/MoS2 cells at each discharge depth were analyzed through characterization of the crystallographic changes by employing ex situ X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Finally, Na/MoS2 reaction mechanism was suggested.