Hydrothermal Synthesis of Copper Sulfide Flowers and Nanorods for Lithium-Ion Battery Applications

Copper sulfide flowers and nanorods were prepared by a surfactant-assisted hydrothermal process, using copper chloride and thiourea or thioacetamide as reactant in the presence of polyethylene glycol (PEG). The influences of sulfurating reagents and reaction temperatures on the morphologies of CuS particles are investigated. The microstructures and morphologies of as-prepared CuS were characterized by using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray analysis (EDX), respectively. The morphologies of CuS prepared with Tu are mainly flower-like, but the morphologies of CuS prepared with TAA are nanorods and microtubes under the same reaction conditions. Due to the stability of structure, the CuS prepared with thiourea presents better cyclability compared to the CuS prepared with thioacetamide. The results reveal that sulfur sources and reaction temperature play important roles on controlling the morphologies and electrochemical performance of CuS particles as cathode materials for lithium ion batteries (LIBs). The CuS synthesized with thiourea at 140°C shows a highest discharge capacity (the first capacity is 187.1 mAh g-1 and 71.72 mAh g-1 after 50 cycles) at 30 mA g-1 current density at room temperature in the range of 1.8-2.6 V.