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1.
Urchin-like nano/micro-structured Fe3O4/C composite has been successfully synthesized using inexpensive starting materials. The urchin-shaped nano/micro-structure consisted of several oriented nanorods. TEM analysis revealed that there is a large number of pores and uniform amorphous carbon distribution at a nanoscale in the nanorods walls. As used in lithium-ion batteries, the mesoporous Fe3O4/C anode delivered a higher reversible capacity of about 830 mAh g−1 at 0.1 C up to 50 cycles, as well as enhanced high-rate capability compared with urchin-like Fe2O3 and commercial Fe3O4. The improvements can be attributed to the combined effects of the nano/micro-architecture, the porosity, and the ultra-fine carbon matrix, where the three factors would contribute to possess both the merits of nanometer-sized building blocks and micro-sized assemblies and provide high electronic conductivity. It is believed that the results of this study offer new prospects for improving the lithium storage capacity of metal oxides by controlling both architecture and composition. 相似文献
2.
Urchin-like nano/micro-structured Fe 3O 4/C composite has been successfully synthesized using inexpensive starting materials. The urchin-shaped nano/micro-structure consisted of several oriented nanorods. TEM analysis revealed that there is a large number of pores and uniform amorphous carbon distribution at a nanoscale in the nanorods walls. As used in lithium-ion batteries, the mesoporous Fe 3O 4/C anode delivered a higher reversible capacity of about 830?mAh?g ?1 at 0.1?C up to 50 cycles, as well as enhanced high-rate capability compared with urchin-like Fe 2O 3 and commercial Fe 3O 4. The improvements can be attributed to the combined effects of the nano/micro-architecture, the porosity, and the ultra-fine carbon matrix, where the three factors would contribute to possess both the merits of nanometer-sized building blocks and micro-sized assemblies and provide high electronic conductivity. It is believed that the results of this study offer new prospects for improving the lithium storage capacity of metal oxides by controlling both architecture and composition. 相似文献
3.
This work introduces an effective, inexpensive, and large-scale production approach to the synthesis of Fe 2O 3 nanoparticles with a favorable configuration that 5 nm iron oxide domains in diameter assembled into a mesoporous network. The phase structure, morphology, and pore nature were characterized systematically. When used as anode materials for lithium-ion batteries, the mesoporous Fe 2O 3 nanoparticles exhibit excellent cycling performance (1009 mA h g − 1 at 100 mA g − 1 up to 230 cycles) and rate capability (reversible charging capacity of 420 mA h g − 1 at 1000 mA g − 1 during 230 cycles). This research suggests that the mesoporous Fe 2O 3 nanoparticles could be suitable as a high rate performance anode material for lithium-ion batteries. 相似文献
4.
The Si/MgO/graphite composite was synthesized by high energy ball-milling and evaluated as a durable anode for lithium-ion batteries. EDX mapping indicated that Si was dispersed homogeneously in the MgO matrix. The composite delivered an initial capacity of ~ 700 mAh/g and maintained a capacity of 630 mAh/g after 74 cycles at 0.5 mA/cm 2; even at 8 mA/cm 2 it delivered more than 85% of its capacity. Its volumetric capacity is double that of carbon. The coulombic efficiency climbed from 77% in the first cycle to above 99.5% after 20 cycles, and retained that value. 相似文献
5.
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. 相似文献
6.
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. 相似文献
7.
Heterostructured ZnFe 2O 4–graphene nanocomposites are synthesized by a facile hydrothermal method. The as-prepared ZnFe 2O 4–graphene nanocomposites are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis and galvanostatic charge and discharge measurements. Compared with the pure ZnFe 2O 4 nanoparticles, the ZnFe 2O 4–graphene nanocomposites exhibit much larger reversible capacity up to 980 mAh g −1, greatly improved cycling stability, and excellent rate capability. The superior electrochemical performance of the ZnFe 2O 4–graphene nanocomposites could be attributed to the synergetic effect between the conducting graphene nanosheets and the ZnFe 2O 4 nanoparticles. 相似文献
8.
Journal of Solid State Electrochemistry - Exploring the fast-charge anodes is crucial to meet the needs of lithium-ion battery (LIB) markets. Here, a hollow hexagonal mesoporous TiO2/carbon... 相似文献
9.
The SnO 2 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 SnO 2 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 SnO 2 sheet/graphite composite displays superior Li-battery performance with large reversible capacity and good cyclic performance. 相似文献
10.
The pristine CeVO4 and CeVO4/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method.From the X-ray diffra... 相似文献
11.
Iron oxide (Fe 2O 3) was utilized to enhance the electrochemical properties of SiO as a promising anode for Li-ion batteries. An SiO/Fe 2O 3 composite, composed of SiO coated with Fe 2O 3 nanoparticles, was synthesized by mechanical milling and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The electrochemical properties of the SiO/Fe 2O 3 composite, SiO, and mechanically milled SiO as anodes for Li-ion batteries were then investigated. The SiO/Fe 2O 3 composite showed superior performance compared with the two Fe 2O 3-free SiO samples, including an increased initial coulombic efficiency, enhanced rate capability, and better capacity retention. 相似文献
14.
Graphitized carbon (GC) and graphene (GE) modified Fe 2O 3/Li 4Ti 5O 12 (LTO) composites have been synthesized via a solid‐state reaction, respectively. The structure, morphology and electrochemical performance of the materials have also been characterized with X‐ray diffraction (XRD), scanning electron microscope (SEM) with an energy dispersive spectroscopy (EDS) system, X‐ray photoelectron spectrometer (XPS), Fourier transform infrared spectroscopy (FTIR) and electrochemical measurements. The discharge capacities of Fe 2O 3/LTO, GC/Fe 2O 3/LTO and GE/Fe 2O 3/LTO are 100.2 mAh g ?1, 207.5 mAh g ?1 and 238.9 mAh g ?1 after 100 cycles at the current density of 176 mA g ?1. The cyclic stability and rate capability are in the order of GE/Fe 2O 3/LTO > GC/Fe 2O 3/LTO > Fe 2O 3/LTO because of the synergistic effect between GC (GE) and Fe 2O 3/LTO. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
15.
Nitridated mesoporous Li 4Ti 5O 12 spheres were synthesized by a simple ammonia treatment of Li 4Ti 5O 12 derived from mesoporous TiO 2 particles and lithium acetate dihydrate via a solid state reaction in the presence of polyethylene glycol 20000. The carbonization of polyethylene glycol could effectively restrict the growth of primary particles, which was favorable for lithium ions diffusing into the nanosized TiO 2 lattice during the solid state reaction to form a pure phase Li 4Ti 5O 12. After a subsequent thermal nitridation treatment, a high conductive thin TiO x N y layer was in situ constructed on the surface of the primary nanoparticles. As a result, the nitridated mesoporous Li 4Ti 5O 12 structure, possessing shorter lithium-ion diffusion path and better electrical conductivity, displays significantly improved rate capability. The discharge capacity reaches 138 mAh?g ?1 at 10 C rate and 120 mAh?g ?1 at 20 C rate in the voltage range of 1–3 V. 相似文献
16.
In the present work,an interconnected sandwich carbon/Si-SiO_2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition(TVD).The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%. 相似文献
17.
A novel anode material, LiNb 3O 8, whose theoretical capacity is 389 mAh/g assuming two-electron transfers (Nb 5+ → Nb 3+), was prepared by a solid state reaction. It was found that only 3.8 Li per unit formula can be inserted into the as-prepared micro-sized sample. However, when the sample was ball-milled with acetylene black to form a mixed conducting network, 5.4 Li can be inserted in the same voltage range and 2.8 Li (180 mAh/g) can be reversibly extracted after 50 cycles. 相似文献
18.
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. 相似文献
19.
In the present work,an interconnected sandwich carbon/Si-SiO2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition(TVD).The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%. 相似文献
20.
Graphene nanosheets (GNSs) were prepared from artificial graphite by oxidation, rapid expansion and ultrasonic treatment. The morphology, structure and electrochemical performance of GNSs as anode material for lithium-ion batteries were systematically investigated by high-resolution transmission electron microscope, scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy and a variety of electrochemical testing techniques. It was found that GNSs exhibited a relatively high reversible capacity of 672 mA h/g and fine cycle performance. The exchange current density of GNSs increased with the growth of cycle numbers exhibiting the peculiar electrochemical performance. 相似文献
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