Herein, three-dimensional (3D) N-doped reduced graphene oxide (N-rGO) nanosheets were decorated with a uniform distribution of Co-Ni-S (CNS) nanoparticles to form the CNS/N-rGO composite as a sulfur host material for lithium-sulfur batteries. The CNS nanoparticles and N in CNS/N-rGO strongly interact with polysulfides, whereas graphene, as a conductive network, can improve its electrical conductivity. A CNS/N-rGO/sulfur composite cathode was prepared via the sulfur melting diffusion method. The electrochemical study showed that the CNS/N-rGO/sulfur cathode delivered an initial discharge capacity of 1430 mA h g-1 at a current density of 0.1C. Moreover, it retained a specific capacity of 685 mA h g-1 after 300 cycles at 0.5C with a coulombic efficiency of 98%, which was better than that of commercial rGO. This composite was used as a sulfur cathode for a lithium-sulfur battery, exhibiting excellent rate capability and remarkable performance in terms of long cycling stability.
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