Copper incorporated CuxMo6S8 (x ≥ 1) Chevrel-phase cathode materials synthesized by chemical intercalation process for rechargeable magnesium batteries†
Abstract
An effective method to control the composition of CuxMo6S8 Chevrel-phase is introduced to incorporate more than 1 mol of Cu in the Mo6S8 Chevrel cathode material for rechargeable Mg batteries. By adopting a chemical intercalation process, CuxMo6S8 (x ≥ 1) ternary Chevrel phases can be successfully synthesized up to x = 1.7. Through a combination of various structural and electrochemical analyses, it is confirmed that our synthesized products have a homogeneous size and single phase, in contrast with the product made by the conventional method controlling the chemical leaching time, which leads to a high reversible capacity close to the theoretical value at the Cu1.3Mo6S8 electrode. Furthermore, the electrode exhibits excellent discharge rate capability and cycling performance at room temperature. As x in CuxMo6S8 increases further, while the specific capacity decreases, capacity retention is well maintained during cycles. The information obtained from this study would contribute for the utilization of ternary Chevrel phases as cathode materials for rechargeable Mg batteries.