ZnO is a promising anode material for lithium-ion batteries (LIBs); however, its practical application is hindered primarily by its large volume variation upon lithiation. To overcome this drawback, we synthesized ZnO/graphene composites using the combination of a simple hydrothermal reaction and spray drying. These composites consisted of well-dispersed ZnO nanorods anchored to graphene. The folded three-dimensional graphene spheres provided a high conductivity, high surface area, and abundant defects. LIB with an anode composed of our novel ZnO/graphene material demonstrated a high initial discharge capacity of 1583 mAh g−1 at 200 mA g−1.
Lithium-sulfur (Li-S) batteries are the most prospective energy storage devices. Nevertheless, the poor conductivity of sulfur and the shuttling phenomenon of polysulfides hinder its application. In this paper, flower-like MoS2/graphene nanocomposite is prepared and deposited on a multi-functional separator to enhance the electrochemical behavior of Li-S batteries. The results demonstrated that the MoS2/graphene-coated separator is contributing to inhibit the shuttling phenomenon of polysulfides and improve the integrity of sulfur electrode. The initial discharge capacity of the battery using MoS2/graphene-coated separator at 0.2 C was up to 1516 mAh g−1. After 100 cycles, a reversible capacity of 880 mAh g−1 and a coulombic efficiency of 98.7% were obtained. The improved electrochemical behavior can be due to the nanostructure and Mo-S bond of the MoS2/graphene composite, which can combine physical shielding and chemisorption to prohibit the shuttle effect of polysulfides. The results prove that the MoS2/graphene-coated separator has the potential for feasible application in Li-S batteries to enhance their electrochemical performance.
By using ZnO nanorods as an ideal sacrificial template, one-dimensional (1-D) ZnS nanotubes with a mean diameter of 10 nm were successfully synthesized by hydrothermal method. The phase composition and microstructure of the ZnS nanotubes were characterized by using XRD (X-ray diffraction), SEM (scanning electron micrograph), and TEM (transmission electronic microscopy) analysis. X-ray photoelectron spectroscopy (XPS) and nitrogen sorption isotherms measurements were also used to study the information on the surface chemical compositions and specific surface area of the sample. The prepared ZnS nanotubes were used as anode materials in lithium-ion batteries. Results show that the ZnS nanotubes deliver an impressive prime discharge capacity as high as 950 mAh/g. The ZnS nanotubes also exhibit an enhanced cyclic performance. Even after 100 charge/discharge cycles, the discharge capacity could still remain at 450 mAh/g. Moreover, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were also carried out to evaluate the ZnS electrodes.