Electrochemical characterization of novel layered Cu2MS4 materials for Li-ion batteries (M=Mo).

Abstract: Electrochemical performance of Cu2MoS4 was evaluated. When the cutoff potential is limited between 1.6 and 3.0V, the material can give stable cycle performance of up to 100mAhg−1. However, the material shows slow kinetics within this region. The material can give a discharge capacity of up to 653mAhg−1 when discharged to 0.6V vs. Li/Li+, with a first cycle efficiency of 61.3%. This corresponds to an insertion of 8.5Li and an extraction of 5.2Li from the material. XRD and XPS measurements both suggest Cu displacement from the material during discharge and charge, which is a possible reason for the poor cycle stability of the material. A reaction mechanism is proposed based on the XPS analysis. Better cycle performance is observed for Cu2MoS4/GO composite. [Copyright &y& Elsevier]