Facile synthesis of copper sulfide wire/carbon nanotube composite with improved sodium storage performance

One-dimensional copper sulfide (CuS) wires were realized by the acrylamide-assisted hydrothermal process using Cu(NO₃)₂ and thiourea (NH₂CSNH₂) as reactants at 100 °C. A copper sulfide/carbon nanotube (CNTs) composite was fabricated as a similar method with the addition of CNTs. The samples are characterized by XRD, SEM, TEM, and Raman scattering spectra, respectively. The influence of reaction temperature and amine on the morphologies of CuS nanocrystals was investigated. As anode materials for sodium-ion batteries, the electrochemical studies show that the CuS/CNT composite electrode delivers a higher reversible capacity of 428.1 mA h g⁻¹ at 0.1 A g⁻¹ for the 100th cycle, because CNTs can be a conductive agent to provide a fast path for electron transportation, compared with the bare CuS wires (280 mAh·g⁻¹ after 100 cycles). The synthesis results indicate that the amine-directed synthesis strategy of copper sulfide could be extended for the preparation of other metal sulfide nanostructures. Further, the incorporation of the CNT matrix into the copper sulfide is an effective approach to enhance the electrochemical performance of CuS.