In this work

a simple one-pot hydrothermal method was developed to synthetize CuS/C composite in one-step by using copper nitrate trihydrate (Cu(NO3)2·3H2O) as copper source

thiourea as sulfur source and D-glucose sodium as complexing agent. The composition

microstructure and morphology of the CuS/C composite were characterized by X ray diffraction (XRD)

Raman spectroscopy

organic element analyzer and scanning electron microscopy (SEM). It was found that the as-synthesized composite was mainly composed of novel petaloid CuS microspheres

which provided many paths for ion diffusion and increased specific area with about 6% of amorphous carbon microspheres (mass fraction). The composite exhibited a maximum specific capacitance of up to 719 F·g-1 at 1 A·g-1

while the specific capacitance was 382 F·g-1 at 1 A·g-1 for CuS prepared without using complexing agent. The long-term constant current charge-discharge test showed that the CuS/C composite exhibited excellent long cycle life with capacitance retention of 80% after 1000 cycles at 1 A·g-1. Although due to low melting point (220℃) of CuS

heat treatment at high temperature cannot be employed to transform the amorphous carbon microspheres into crystalline carbon for further improving the electrochemical properties

the one-pot hydrothermal method was likely to open a new way for directly synthetizing transition metal compounds/carbon composite materials by a one-step process

especially for transition metal compounds with high melting point/carbon composites with the possibility of carbonization treatment at high temperature.