Superior cycle performance of Sn@C/graphene nanocomposite as an anode material for lithium-ion batteries

A novel anode material for lithium-ion batteries, tin nanoparticles coated with carbon embedded in graphene (Sn@C/graphene), was fabricated by hydrothermal synthesis and subsequent annealing. The structure and morphology of the nanocomposite were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The size of the Sn@C nanoparticles is about 50-200 nm. The reversible specific capacity of the nanocomposite is ∼662 mAh g⁻¹ at a specific current of 100 mA g⁻¹ after 100 cycles, even ∼417 mAh g⁻¹ at the high current of 1000 mA g⁻¹. These results indicate that Sn@C/graphene possesses superior cycle performance and high rate capability. The enhanced electrochemical performances can be ascribed to the characteristic structure of the nanocomposite with both of the graphene and carbon shells, which buffer the volume change of the metallic tin and prevent the detachment and agglomeration of pulverized tin.     

Influence of graphene oxide on electrochemical performance of Si anode material for lithium-ion batteries

We have developed a Si/graphene oxide electrode synthesized via ultrasonication-stirring method under alkaline condition. Scanning electron microscopy(SEM), transmission electron microscope(TEM), EDS dot-mapping and high-resolution transmission electron microscopy(HRTEM) results show that Si particles are evenly dispersed on the graphene oxide sheets. The electrochemical performance was investigated by galvanostatic charge/discharge tests at room temperature. The results revealed that Si/graphene oxide electrode exhibited a high reversible capacity of 2825 mAh/g with a coulombic efficiency of 94.6%at 100 mA/g after 15 cycles and a capacity retention of 70.8% after 105 cycles at 4000 mA/g. These performance parameters show a great potential in the high-performance batteries application for portable electronics, electric vehicles and renewable energy storage.     

Pb-sandwiched nanoparticles as anode material for lithium-ion batteries

A sandwiched SiC@Pb@C nanocomposite was prepared through a simple ball-milling route and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The SiC@Pb@C nanocomposite exhibits a much improved reversible capacity and cycling life as compared with a bare Pb anode. A reversible volumetric capacity of >1,586 mAh cm⁻³ (207 mAh g⁻¹) can be maintained after 600 cycles of charge and discharge in the potential interval between 0.005 and 1.0 V, which far exceeds those reported previously in the literature. The enhanced electrochemical performance is ascribed to the sandwiched structure in which nanosized Pb particles were anchored in between the rigid SiC core and the outer carbon shell, mitigating the damage done by the large volume change of the Pb interlayer during the alloying/dealloying process.     

Electrochemical studies of few-layered graphene as an anode material for Li ion batteries

Few-layered graphene (FLG) with specific surface area of only ~8.2 m² g^?1 was synthesized from graphene oxide (GO) using microwave-assisted exfoliation. GO was prepared using modified Hummers method. Few-layered nature of the exfoliated material was confirmed by electron microscopy, X-ray and electron diffraction, and Raman spectroscopy. Coin cells were fabricated using FLG as an anode and lithium metal as a counter electrode. The cells were tested using cyclic voltammetry and galvanostatic cycling techniques. FLG showed reversible capacity values of ~400 and ~250 mAh g^?1 at current rates of 0.1 and 1 C, respectively. Columbic efficiency was more than 98 % while cycle to cycle capacity fading was less than 2 %. Maximum discharge or charging capacity was below 0.3 V, a preferable characteristic for achieving ideal anodic behavior.     

Electrochemical study on different layers of graphene based TiO2/graphene composites as an anode for lithium-ion batteries

Research on Chemical Intermediates - In order to explore the influence of the layers of graphene on the lithium-ion battery composites, to increase the electroconductivity of TiO2 and...     

Cobalt oxide–graphene nanocomposite as anode materials for lithium-ion batteries

Composites of Co₃O₄/graphene nanosheets are prepared and characterized by X-ray diffraction and scanning electron microscopy. Their electrochemical behavior as anode materials of lithium-ion rechargeable batteries is investigated by galvanostatic discharge/charge measurements and cyclic voltammetry. The composite is composed of Co₃O₄ nanorods (around 20–40 nm in diameter) and nanoparticles (around 10 nm in diameter) distributed within the graphene matrix. The specific capacity of the composite is higher than both Co₃O₄ and graphene nanosheets. The cycling stability of Co₃O₄ is obviously enhanced by compositing with graphene. After 100 cycles, the discharge and charge capacity of the composite is 1,005 and 975 mAh g⁻¹, respectively, and the irreversible capacity loss is less than 3%.

     

Enhanced electrochemical performance of carbon-coated TiO2 nanobarbed fibers as anode material for lithium-ion batteries

We report the electrochemical performance of carbon-coated TiO₂ nanobarbed fibers (TiO₂@C NBFs) as anode material for lithium-ion batteries. The TiO₂@C NBFs are composed of TiO₂ nanorods grown on TiO₂ nanofibers as a core, coated with a carbon shell. These nanostructures form a conductive network showing high capacity and C-rate performance due to fast lithium-ion diffusion and effective electron transfer. The TiO₂@C NBFs show a specific reversible capacity of approximately 170 mAh g^− 1 after 200 cycles at a 0.5 A g^− 1 current density, and exhibit a discharge rate capability of 4 A g^− 1 while retaining a capacity of about 70 mAh g^− 1. The uniformly coated amorphous carbon layer plays an important role to improve the electrical conductivity during the lithiation–delithiation process.     

Cycling parameters of MAG graphite as anode material for lithium-ion batteries

Integrated analysis of the cycling parameters (reversible specific capacity, Coulomb efficiency, irreversible loss of cycle capacity, accumulated irreversible capacity, and retention of reversible capacity) of synthetic graphite of MAG brand as an active material for the negative electrode of lithium-ion batteries was made.     

A high-capacity graphene nanosheet material with capacitive characteristics for the anode of lithium-ion batteries

Graphene nanosheets are prepared from H₂ thermal reduction of graphite oxide at 300 °C. The graphite oxide interlayer has readily been expanded through chemical oxidation of meso-carbon micro-beads graphite raw material. After H₂ reduction, the carbon/oxygen ratio of graphene is increased from that of graphite oxide due to the removal of oxygen-containing functional groups as it is demonstrated from IR spectra. The d-spacing of resulting graphene nanosheets is increased to 0.37 nm, which facilitates lithium intercalation. Such synthesized graphene nanosheet material as anode of lithium-ion battery has exhibited high reversible discharge capacity of 1,540 mAh g⁻¹ at a current density of 50 mA g⁻¹, and the coulumbic efficiency was 97% over 50 cycles. The discharge curve of the anode material shows a continuously increased voltage profile, which is a characteristic of a capacitive material.     

High performance TiP2O7 nanoporous microsphere as anode material for aqueous lithium-ion batteries

This work developed a facile way to mass-produce a carbon-coated TiP_2O_7 nanoporous microsphere(TPO-NMS) as anode material for aqueous lithium-ion batteries via solid-phase synthesis combined with spray drying method. TiP_2O_7 shows great prospect as anode for aqueous rechargeable lithium-ion batteries(ALIBs) in view of its appropriate intercalation potential of-0.6 V(vs. SCE) before hydrogen evolution in aqueous electrolytes. The resulting sample presents the morphology of secondary microspheres(ca. 20 μm) aggregated by carbon-coated primary nanoparticles(100 nm), in which the primary nanoparticles with uniform carbon coating and sophisticated pore structure greatly improve its electrochemical performance. Consequently, TPONMS delivers a reversible capacity of 90 mA h/g at 0.1 A/g, and displays enhanced rate performance and good cycling stability with capacity retention of 90% after 500 cycles at 0.2 A/g. A full cell containing TPO-NMS anode and LiMn_2O_4 cathode delivers a specific energy density of 63 W h/kg calculated on the total mass of anode and cathode. It also shows good rate capacity with56% capacity maintained at 10 A/g rate(vs. 0.1 A/g), as well as long cycle life with the capacity retention of 82% after 1000 cycles at 0.5 A/g.     

Iron sulfide-embedded carbon microsphere anode material with high-rate performance for lithium-ion batteries

Iron sulfide-embedded carbon microspheres were prepared via a solvothermal process and show high specific capacity and excellent high-rate performance as anode material for lithium-ion batteries.     

Tin oxide-titanium oxide/graphene composited as anode materials for lithium-ion batteries

A tin oxide-titanium oxide/graphene (SnO₂-TiO₂/G) ternary nanocomposite as high-performance anode for Li-ion batteries was prepared via a simple reflux method. The graphite oxide (GO) was reduced to graphene nanosheet, and the SnO₂-TiO₂ nanocomposites were evenly distributed on the graphene matrix in the SnO₂-TiO₂/G nanocomposite. The as-prepared SnO₂-TiO₂/G nanocomposites were employed as anode materials for lithium-ion batteries, showing an outstanding performance with high reversible capacity and long cycle life. The composite delivered a superior initial discharge capacity of 1,594.6 mAh g^?1 and a reversible specific capacity of 1,500.3 mAh g^?1 at a current density of 100 mA g^?1. After 100 cycles, the reversible discharge capacity was still maintained at 1,177.4 mAh g^?1 at a current density of 100 mA g^?1 with a high retained rate of reversible capacity of 73.8 %. The addition of small amount of TiO₂ nanoparticles improved the cycling stability and specific capacity of SnO₂-TiO₂/G nanocomposite, obviously. The results demonstrate that the SnO₂-TiO₂/G nanocomposite is a promising alternative anode material for practical Li-ion batteries.     

Hydrothermal exfoliated molybdenum disulfide nanosheets as anode material for lithium ion batteries

Ultrathin MoS2nanosheets were prepared in high yield using a facile and effective hydrothermal intercalation and exfoliation route. The products were characterized in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the high yield of MoS2nanosheets with good quality was successfully achieved and the dimensions of the immense nanosheets reached 1 μm–2 μm. As anode material for Li-ion batteries, the as-prepared MoS2nanosheets electrodes exhibited a good initial capacity of 1190 mAh g-1and excellent cyclic stability at constant current density of 50 mA g-1. After 50 cycles, it still delivered reversibly sustained high capacities of 750 mAh g-1.     

First-principles studies on doped graphene as anode materials in lithium-ion batteries

Using density functional theory computations, we investigated Li adsorption, diffusion, and desorption in pristine, B- or N-doped graphene. Compared with pristine graphene, B-doping significantly enhances Li adsorption, whereas Li adsorption is slightly weakened on N-doped graphene, which should be attributed to the different electronic structures due to doping. Li diffusion on various graphene systems was also computed through nudged elastic band method, and the results revealed that Li diffusion on N-doped graphene is faster than on pristine and B-doped graphene. Moreover, for Li desorption from the graphene substrate, N-doped graphene showed the lowest desorption barrier. Our results are in agreement with recent experimental reports and also demonstrate that N-doped graphene is a promising anode material with high-rate charge/discharge ability for Li-ion batteries.     

Hydrothermal exfoliated molybdenum disulfide nanosheets as anode material for lithium ion batteries

Ultrathin MoS2nanosheets were prepared in high yield using a facile and effective hydrothermal intercalation and exfoliation route. The products were characterized in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the high yield of MoS2nanosheets with good quality was successfully achieved and the dimensions of the immense nanosheets reached 1 μm–2 μm. As anode material for Li-ion batteries, the as-prepared MoS2nanosheets electrodes exhibited a good initial capacity of 1190 mAh g-1and excellent cyclic stability at constant current density of 50 mA g-1. After 50 cycles, it still delivered reversibly sustained high capacities of 750 mAh g-1.     

Electrospun tin-carbon nanocomposite as anode material for all solid state lithium-ion batteries

Journal of Solid State Electrochemistry - All-solid-state batteries represent the next generation of electrochemical energy storage systems. A tin-carbon nanocomposite material is prepared by the...     

SnO2 sheet/graphite composite as anode material with improved electrochemical performance for lithium-ion batteries

The SnO₂ sheet/graphite composite was synthesized by a hydrothermal method for high-capacity lithium storage. The microstructures of products were characterized by XRD and FE-SEM. The electrochemical performance of SnO₂ sheet/graphite composite was measured by galvanostatic charge/discharge cycling and EIS. The first discharge and charge capacities are 1,072 and 735 mAh g^?1 with coulombic efficiency of 68.6 %. After 40 cycles, the reversible discharge capacity is still maintained at 477 mAh g^?1. The results show that the SnO₂ sheet/graphite composite displays superior Li-battery performance with large reversible capacity and good cyclic performance.     

Graphene anchored with mesoporous NiO nanoplates as anode material for lithium-ion batteries

Graphene is an excellent substrate to load nanomaterials for energy applications due to its large surface area, excellent conductivity, mechanical strength, and chemical stability. In this study, thermal exfoliated functionalized graphene sheets with good conductivity and high BET surface area are anchored with mesoporous NiO nanoplates by in situ chemical synthesis approach. Electrochemical characterization shows that functionalized graphene sheets–NiO sample exhibits a high capacity of about 700 mAh/g at a discharge current density of 100 mA/g and a good cycling ability. The high capacity and good cycling ability of functionalized graphene sheets –NiO material were attributed to the intimate interaction between the graphene sheets and NiO nanoplates. The graphene sheets not only enhance the conductivity of NiO nanoplates but also improve the structure stability of NiO nanoplates. Furthermore, the mesoporous structure of NiO nanoplates is available to the transfer of electrolyte. Such functionalized graphene sheets–NiO nanocomposite could be a promising candidate material for a high-capacity, low cost, and nontoxic anode for lithium-ion batteries.