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Reduced graphene oxide@nickel oxide (NiO) composites were prepared through a simple hydrothermal reaction combined with a heat treatment. The reduced graphene oxide@NiO composites are composed of NiO nanosheets uniformly attaching on both sides of cross-linked reduced graphene oxide. Some favorable electrochemical performances in specific capacity, cycling performance, and rate capability are achieved using the porous nanocomposites as an anode for lithium-ion batteries. And the reversible specific capacity can reach up to1023 mAh g−1 at 400 mA g−1 after 200 cycles. A full cell consists of a commercial LiCoO 2 cathode and the reduced graphene oxide NiO@-3 nanocomposites anode, is able to hold a high capacity of 772 mAh g−1 at 400 mA g−1 after 200 cycles. The three-dimensional reduced graphene oxide plays a key role in enhancing the electrical conductivity of the electrode materials; and it effectively prevents the NiO nanoparticles from dropping off the electrode and buffers the volume variation during the discharge-charge process. The reduced graphene oxide@NiO nanocomposites present a great potential to be a promising electrode material in the near future for lithium-ion batteries. Image 1 • NiO nanosheets anchoring on rGO composite was developed. • It involves immersing and hydrothermal process followed by thermal treatment. • The hierarchical rGO@NiO anodes exhibit high stable capacity and rate performance. • High performance is ascribed to the special hierarchical rGO@NiO nanocomposites. [ABSTRACT FROM AUTHOR]

Graphical abstract A sandwich-structured ZnCo 2 O 4 @reduced graphene oxide nanocomposites acquired through an accessible dipping and hydrothermal process followed by heat treatment, exhibit ascendant lithium-ion storage properties. Highlights • A special sandwich-nanostructured ZnCo 2 O 4 @rGO composite was developed. • It involves accessible dipping and hydrothermal process followed by heat treatment. • The sandwiched ZnCo 2 O 4 @rGO anodes exhibit high stable capacity and rate performance. • High performance is ascribed to the special sandwiched ZnCo 2 O 4 @rGO nanocomposite. Abstract A stereo-structured ZnCo 2 O 4 @reduced graphene oxide (ZCO@rGO) nanocomposite was prepared by an adsorption process combined with a hydrothermal process and calcination. Three-dimensional (3D) rGO was used as a template, and ZCO nanoparticles were anchored uniformly and compactly on both sides of the rGO. In half cells, the nanocomposite exhibits decent electrochemical characteristics, including a high cycling capability of 1613 mAh g−1 at 500 mA g−1 over 400 cycles. In addition, when matched with a commercial LiCoO 2 cathode, the ZCO@rGO//LiCoO 2 full cell also delivers favorable electrochemical properties, including a capacity of 1589 mAh g−1 over 140 cycles at 100 mAh g−1, making it a prospective candidate for high-energy-density lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Heterostructure of NiSe 2 /MnSe nanoparticles distributed evenly over cross-linked N-doped carbon nanosheets (NM@NCNs) were developed as anode materials via a hydrothermal strategy followed by an in situ selenization process for the first time. Benefiting from the sandwich structure, bimetallic effect and high conductivity of NCNs, the obtained NM@NCNs manifest excellent sodium storage properties. [Display omitted] • Heterostructure of NiSe 2 /MnSe nanoparticles distributed evenly over cross-linked N-doped carbon nanosheets was developed. • It involves a facile hydrothermal method followed by an in situ selenization process. • The NM@NCNs composite anode exhibited high stable capacity and rate performance. • High performance is due to bimetallic effect, sandwich structure and superior conductivity of NCNs. Heterostructure of NiSe 2 /MnSe nanoparticles distributed evenly over cross-linked N-doped carbon nanosheets (NM@NCNs) was developed as anode material via a hydrothermal strategy followed by an in situ selenization process. The anode delivered a high reversible capacity of 487 mAh g−1 at 5 A g−1 after 200 cycles and an excellent rate capacity of 269 mAh g−1 at a high current density of 10 A g−1. In particular, under −10 °C, the electrode still maintained a satisfactory rate capability for 271 mAh g−1 at 5 A g−1. The advanced electrochemical performance is related with the following merits. First, NiSe 2 /MnSe nanoparticles as bimetallic selenide can offer a higher specific capacity than monometallic selenide. Moreover, the rich redox-active sites provided by NiSe 2 /MnSe can accelerate the electrochemical reaction. Second, cross-linked NCNs with high electronic conductivity can serve as a substrate, preventing nanoparticle agglomeration and alleviating the variations in volume. Third, NiSe 2 /MnSe heterostructure proved by X-ray photoelectron spectroscopy (XPS) results can form lattice distortion, enhancing Na+ diffusion in the redox process. The possible electrochemical process was demonstrated by ex situ X-ray diffraction, and the Na+ diffusion rate of the NM@NCNs anode was calculated using the galvanostatic intermittent titration technique. [ABSTRACT FROM AUTHOR]

Three-dimensional nanostructured rGO@NiS nanocomposites are synthesized by a solvothermal process, and show an enhanced lithium-ion storage performance. • rGO@NiS composites with a favorable nanostructure were developed. • Synthesis process consists of accessible dipping and hydrothermal reaction. • rGO@NiS composite anode shows an improved reversible capacity and rate behavior. • Synergistic effect of NiS NPs and rGO contributes to the high performance. Reduced graphene oxide@nickel sulfide (NiS) composites are synthesized by a solvothermal method. Uniformly dispersed NiS nanoparticles with a size of 15∼25 nm are embedded to the surface of a three-dimensional (3D) reduced graphene oxide. The favorable 3D-framework with a large amount of pores has been characterized systematically. As a Li-ion battery anode, the reduced graphene oxide@NiS anode keeps a reversible capacity of 1328.7 mAh g-1 at 0.1 A g-1 after 120 cycles. Meanwhile, it shows an enhanced rate capability of 673.6 mAh g-1 at 1.0 A g-1. The enhanced reversible capacity and cycling stability is ascribed to the reduced graphene oxide and its unique 3D porous nanostructure. Furthermore, the existence of C‒S bonds make reduced graphene oxide and nickel sulfide in the composite combine better during the cycling process, and enhance their synergistic effect. Since that, the conductivity, volume-variation and active sites of the composites are greatly improved. [ABSTRACT FROM AUTHOR]

Abstract Tin(IV) oxide@reduced graphene oxide nanocomposites are synthesized using a simple hydrothermal method. The structural and morphological characterizations indicate that the SnO 2 nanoparticles fully and homogeneously anchor on both sides of cross-linked reduced graphene oxide. As an anode material for lithium-ion batteries, the synergistic interaction between the SnO 2 nanoparticles and reduced graphene oxide contributes to good electrochemical behaviors, which enhance the cycling performance and rate capability. For a half-cell, the SnO 2 @reduced graphene oxide nanocomposites as an anode material exhibits a high reversible capacity of 1149 mAh g−1 at a current density of 0.2 A g−1, and a good capacity retention of 67.2% after 130 cycles. For a full-cell, it exhibits a capacity of 648 mAh g−1 at a current density of 0.2 A g−1 after 200 cycles, and the cycling retention of capacity reached 63.5%. The excellent storage capability and cycling performance of lithium-ion batteries make the composite a promising anode material in the practical application of lithium-ion batteries. Graphical abstract Image 1 Highlights • A special sandwich-nanostructured SnO 2 @rGO composites were developed. • It involves immersing 3D rGO in a solution followed by hydrothermal process. • The sandwiched SnO 2 @rGO anodes exhibit high stable capacity and rate performance. • High performance is ascribed to the special sandwiched SnO 2 @rGO nanocomposites. [ABSTRACT FROM AUTHOR]

Gallium oxide as an anode material for lithium-ion batteries has attracted attention because of its high specific capacity. As reported previously, N-doped carbon coated Ga 2 O 3 nanopapers exhibited a high discharge capacity of 477 mAh g−1 after 200 cycles at 0.2 A g−1. But the rate performance and cycling stability of the Ga 2 O 3 –based anode still need to be improved. Herein, Ga 2 O 3 nanotubes coated with N-doped carbon layers (Ga 2 O 3 /N-C NTs) were prepared using MoO 3 nanorods as sacrificial templates followed by a polydopamine coating and heat treatment process. The resulting tubular structure provided cavities for volume changes of the Ga 2 O 3 in the cycling process and shortened the migration path of Li ions and electrons. The N-doped carbon coated Ga 2 O 3 NTs delivered a capacity of 1185.3 mAh g−1 after 100 cycles at 0.1 A g−1 and outstanding stability of 535.5 mAh g−1 after 500 cycles at 1.0 A g−1. This study supplies a novel method for preparing Ga 2 O 3 anode materials to promote the performance of lithium-ion battery. • A special Ga 2 O 3 nanotubes coated with N-doped carbon layers was developed. • It involves a sacrificial template hydrothermal method and a carbon coating process. • Ga 2 O 3 /N-C nanotubes exhibit high stable capacity and superior rate performance. • High electrochemical performance is due to hollow structure and N-carbon coating. [ABSTRACT FROM AUTHOR]

• Tin dioxide nanospheres coated with N-doped carbon film were developed. • It involves a sacrificial template method and a subsequent carbon coating process. • The NC@SnO 2 HNSs exhibit high stable capacity and high rate performance. • High Li storage performance is due to the hollow structure and carbon coating. The preparation of high electrochemical performance SnO 2 -based anode is a crucial promotion to be an alternative electrode for lithium storage. To this end, SnO 2 hollow nanospheres covered with nitrogen-doped carbon shell (denote as NC@SnO 2 HNSs) are designed and synthesized. The NC@SnO 2 HNS electrode could not only improves the conductivity of pure SnO 2 HNSs effectively, but also possesses a large proportion of the cavity (73.8 %), which could cope the strain relaxation. Benefiting from the superior structural design, the NC@SnO 2 HNS electrode exhibits high reversible capacity (868.6 mAh g−1 after 200 cycles at 0.2 A g−1), long-term cycling performance (360.6 mAh g−1 after 500 cycles at 1.0 A g−1) and superior rate performance. [ABSTRACT FROM AUTHOR]

• A special hollow cubic SnO 2 /ZnS@C composite was developed. • It involves a sacrificial template method and a subsequent carbon coating process. • The SnO 2 /ZnS@C composite exhibit high stable capacity and rate performance. • High performance is due to bimetallic effect, hollow structure and carbon coating. [Display omitted] Nanostructured SnO 2 and ZnS have been proved to application prospects in lithium-ion battery. However, some severe challenges, such as rapid capacity decay due to volume expansion during the charge/discharge process and poor conductivity, limit their applications. Herein, a hollow cubic SnO 2 /ZnS@C composite was obtained using ZnSn(OH) 6 cubes as precursor via a hydrothermal reaction and a subsequent carbon coating process. Served as anode material, the SnO 2 /ZnS@C nanocubes exhibit an initial capacity of 1312.8 mAh g−1 at 0.1 A g−1, the coulombic efficiency reaches 73.1%, and it remains 753.5 mA g−1 over 200 cycles. Moreover, rate capacities of SnO 2 /ZnS@C composite reach up to 818, 757 and 693 mAh g−1 at 0.2, 0.5 and 1.0 A g−1, respectively. The SnO 2 /ZnS@C nanocubes exhibit the superior performance due to the synergistic effect of Sn and Zn, the hollow structure and the carbon coating. [ABSTRACT FROM AUTHOR]