Facile synthesis of CuS/rGO composite with enhanced electrochemical lithium-storage properties through microwave-assisted hydrothermal method

Copper sulfide nanoflower/reduced graphene oxide (CuS/rGO) composite is synthesized using Cu(NO3)2, thiourea (Tu) and graphene oxide (GO) powers as the precursor by an ultrafast microwave-assisted hydrothermal method. The electrochemical performances of CuS/rGO composite as anode material of Lithium ion batteries (LIBs) are studied both in ether-based (LiTFSI in DOL/DME) and carbonate-based electrolytes (LiPF6 in EC/DMC). The results reveal that CuS/rGO composite exhibits excellent electrochemical Li-storage properties. The reversible capacity of 422 mA h g−1 and 390 mA h g−1 at a current density of 100 mA g−1 after 70 cycles is obtained in both electrolytes, respectively. Even after 200 charge-discharge cycles at 500 mA g−1 in ether-based electrolyte, the composite delivers a good discharge capacity of 390 mA h g−1 with high capacity retention ratio of 96.7%. The good electrochemical performances of CuS/rGO can be attributed to the synergistic effect of the CuS nanoflower and rGO. Briefly, the introduction of rGO can improve the electronic conductivity of the composite, effectively immobilize the CuS and inhibit the dissolution of the polysulfide intermediates generated during the charge-discharge process.