Composite Anode For Lithium-ion Batteries Research Articles

A facile synthesis of graphite/silicon/graphene spherical composite anode for lithium-ion batteries

The Graphite/Silicon@reGO composite was synthesized via spray drying and subsequent annealing. According to XRD, Raman spectroscopy and FT-IR, graphene was demonstrated to be existed in the composite. Moreover, SEM and TEM were also used to illustrate the morphology of Graphite/Silicon@reGO. Used as anode for lithium-ion battery, it exhibited good cyclability with a high reversible charge capacity of 575.1mAhg−1 and showed a capacity retention ratio of 73.1% after 50 cycles at a current density of 50mAg−1. It also presented good rate capability at different rates of 50–1000mAg−1. EIS test showed that the composite electrode had a lower SEI resistance and charge-transfer resistance due to the existence of graphene.

Magnesium and magnesium-silicide coated silicon nanowire composite anodes for lithium-ion batteries

We synthesized composites consisting of silicon nanowires (SiNWs) coated with magnesium (Mg) and magnesium silicide (Mg2Si) for lithium-ion battery anodes and studied their electrochemical cycling stability and degradation mechanisms. Compared to bare SiNWs, both Mg- and Mg2Si-coated materials show significant improvement in coulombic efficiency during cycling, with pure Mg coating being slightly superior by ∼1% in each cycle. XPS measurements on cycled nanowire forests gave quantitative information on the composition of the SEI layer and showed lower Li2CO3 and higher polyethylene oxide content for coated nanowires, thus revealing a passivating effect towards electrolyte decomposition. Extensive characterization of the microstructure before and after cycling was carried out by scanning- and transmission electron microscopy aided by focused ion beam cross-sectioning. The formation of large voids between the nanowire assembly and the substrate during cycling, causing the nanowires to lose electrical contact with the substrate, is identified as an important degradation mechanism.

Enhanced lithium storage in Fe2O3–SnO2–C nanocomposite anode with a breathable structure

A novel nanocomposite architecture of a Fe2O3-SnO2-C anode, based on clusters of Fe2O3 and SnO2 nanoparticles dispersed along the conductive chains of Super P Li™ carbon black (Timcal Ltd.), is presented as a breathable structure in this paper for lithium-ion batteries. The synthesis of the nanocomposite is achieved by combining a molten salt precipitation process and a ball milling method for the first time. The crystalline structure, morphology, and electrochemical characterization of the synthesised product are investigated systematically. Electrochemical results demonstrate that the reversible capacity of the composite anode is 1110 mA h g(-1) at a current rate of 158 mA g(-1) with only 31% of initial irreversible capacity in the first cycle. A high reversible capacity of 502 mA h g(-1) (higher than the theoretical capacity of graphite, ~372 mA h g(-1)) can be obtained at a high current rate of 3950 mA g(-1). The electrochemical performance is compared favourably with those of Fe2O3-SnO2 and Fe2O3-SnO2-C composite anodes for lithium-ion batteries reported in the literature. This work reports a promising method for the design and preparation of nanocomposite electrodes for lithium-ion batteries.

Preparation and Electrochemical Performance of Carbon nano-tubes/Micro-expanded Graphite Composite Anodes for Lithiumion Batteries

Preparation and Electrochemical Performance of Carbon nano-tubes/Micro-expanded Graphite Composite Anodes for Lithiumion Batteries

Highly Stable Cycling of Si-C Composite Anode for Lithium-Ion Batteries by Using FSI-Based Ionic Liquid

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High gravimetric capacity and long cycle life in Mn3O4/graphene platelet/LiCMC composite lithium-ion battery anodes

We report the synthesis, characterization and battery performance of a novel Mn3O4/graphene composite based on graphene platelets and also an Mn3O4/reduced-graphene-oxide composite for comparison. The electrodes were cast from aqueous dispersions in which lithium carboxymethyl cellulose was used as a binder thus enabling an aqueous based process for anode fabrication. The Mn3O4/graphene-platelet and the Mn3O4/reduced-graphene-oxide composites anode system possess high gravimetric capacities (∼700mAhg−1) and excellent cycling stability (>100 cycles).

Electrochemical Properties of Li1.1V0.75W0.075Mo0.075O2/Graphite Composite Anodes for Lithium-ion Batteries

Novel type Li1.1V0.9-2xWxMoxO2 powders were prepared by a solid-state reaction of Li2CO3, V2O3, WO2 and MoO2 precursors in a nitrogen atmosphere containing 10 mol % hydrogen gas, and assessed as anode materials in lithium-ion batteries. The specific charge and discharge capacities of the Li1.1V0.9-2xWxMoxO2 anodes were higher than those of the bare Li1.1V0.9O2 anode. The cyclic efficiency of these anodes was approximately 73.3% at the first cycle, regardless of the presence of W and Mo doping. The composite anode, which was composed of Li1.1V0.75W0.075Mo0.075O2 (20 wt %) and natural graphite (80 wt %), demonstrated reasonable specific capacity, high cyclic efficiency, and good cycling performance, even at high rates without capacity fading. based on this material could be enhanced significantly because of its low working potential of < 0.3 V vs. Li/Li + during the charge and discharge reactions. The potential of this material as a high-density anode electrode has prompted intensive research on its structure and valence state. Li1.1V0.9O2 has an ordered layered crystalline structure with Li + and V +3 ions occupying alternate (111) planes, and exhibits a hexagonal structure. 8,9 After lithium intercalation, Li1.1V0.9O2 is converted to Li2.1V0.9O2, corresponding to the P-3m1 space group, and the oxidation state of vanadium ions is reduced from V(III) to V(II). The layered structure of Li1.1V0.9O2, gives it a relatively low volume change of 25% during the cycling process compared to that of highly capacitive silicon or tin-based anode materials. On the other hand, the electrochemical properties of Li1.1V0.9O2 might be insufficient for high-current applications owing to its low conductivity. Therefore, surface modification or other treat- ment methods should be applied to enhance the rate cap- ability. Metal doping is one of the most effective methods for improving the electrochemical properties of Li1.1V0.9O2. W and Mo-based oxide materials are used as dopants for Li1.1V0.9O2, which is used as an anode material in lithium-ion batteries. 10,11 These metals are suitable for the preparation of high-density anodes because of their high intrinsic density, low cost and non-toxic environment. In this study, a simple solid-state reaction was used to prepare a conducting Li1.1V0.9-2xWxMoxO2 anode material using a metal doping process. The electrochemical proper- ties of the anodes of these lithium-ion batteries were ex- amined using a range of analytical techniques. Experimental

Improvement of cyclic behavior of a ball-milled SiO and carbon nanofiber composite anode for lithium-ion batteries

The cyclic performance of a composite SiO and carbon nanofiber (CNF) anode was examined for lithium-ion batteries. SiO powder of several micrometers was pulverized using high energy mechanical milling. The SiO was ball-milled for 12 h with CNF to produce a composite electrode material that exhibited excellent cycling performance. A reversible capacity of approximately 700 mAh g −1 was observed after 200 cycles. The excellent cyclic performance was discussed with respect to the change of the valence state of Si by ball-milling. A large irreversible capacity at the first cycle for the SiO/CNF composite electrode was reduced to 2% by chemically pre-charging with a lithium film attached to the rim of the electrode.

Morphology Effects of Graphene Nanosheets on Si/Graphene Composite Anode for Lithium-Ion Batteries

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Sol–gel synthesis and electrochemical performance of Li4Ti5O12/graphene composite anode for lithium-ion batteries

Li4Ti5O12/graphene composite was prepared by a facile sol–gel method. The lattice structure and morphology of the composite were investigated by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The electrochemical performances of the electrodes have been investigated compared with the pristine Li4Ti5O12 synthesized by a similar route. The Li4Ti5O12/graphene composite presents a higher capacity and better cycling performance than Li4Ti5O12 at the cutoff of 2.5–1.0V, especially at high current rate. The excellent electrochemical performance of Li4Ti5O12/graphene electrode could be attributed to the improvement of electronic conductivity from the graphene sheets. When discharged to 0V, the Li4Ti5O12/graphene composite exhibited a quite high capacity over 274mAhg−1 below 1.0V, which was quite beneficial for not only the high energy density but also the safety characteristic of lithium-ion batteries.

Co–Fe layered double hydroxide nanowall array grown from an alloy substrate and its calcined product as a composite anode for lithium-ion batteries

Co–Fe layered double hydroxide (LDH) nanowall arrays (NWAs) have been grown directly from a flexible alloy substrate by a facile hydrothermal method. An ultrasonication test of 30 min towards the as-made Co–Fe LDH NWAs has demonstrated their ultra-robust mechanical adhesion to the substrate. In particular, an in situcarbon-source coating (ISCC) on the Co–Fe LDH NWAs was achieved during their in situ growing process conducted in a glucose-containing reaction solution. After annealing treatment in an argon atmosphere, carbon coated Co–Fe mixed oxide NWAs were evolved from thermal decomposition of LDH precursors and carbonization of glucose, and further investigated as anode materials for lithium-ion batteries (LIBs). When tested, the obtained carbon coated Co–Fe mixed oxide NWAs with improved electrical conductivity exhibited superior electrochemical performance in terms of specific capacity and cyclability as compared to a carbon-free sample and a sample made by the previous carbon-coating method. Our work presents an alternative way to fabricate in situ mixed transition metal oxide nanostructures for high-performance LIBs.

Dimensional Stability of Nanosilicon/Graphite/Carbon Composite Anodes for Lithium-Ion Batteries

Dimensional Stability of Nanosilicon/Graphite/Carbon Composite Anodes for Lithium-Ion Batteries

Preparation and Characterization of Sn-Zn Composite Anode for Lithium-Ion Battery

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Synthesis and Electrochemical Properties of SiOx/C Composite Anode for Lithium-Ion Batteries

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Tin Sulfide and Tin Oxide/Graphite Composite Anodes for Lithium-ion Batteries

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The impact of carbon shell on a Sn–C composite anode for lithium-ion batteries

Spherical Sn–carbon core-shell powders (CSCM/Sn) were synthesized through a resorcinol–formaldehyde microemulsion polymerization performed in the presence of SnO2 powders, followed by carbonization in an inert atmosphere. Scanning electron microscope and X-ray diffractometry analyses showed that the Sn powders were thoroughly encapsulated within the carbon microspheres. The CSCM/Sn presented much better cyclability than the conventional Sn–carbon microsphere composite. In core-shell-structured composite, most of the Sn particles were encased inside carbon microspheres and not easy to aggregate or fall off from the microspheres. The carbon shell suppressed the aggregation of tin particles and alleviated the volume change of tin, and the conductive carbon shell effectively decreased the polarization during cycling, giving rise to better high rate performance and excellent capacity retention ability. It is shown that surface structure plays an important role in alloy/C composite anode materials for lithium-ion battery.

Si/C composite lithium-ion battery anodes synthesized from coarse silicon and citric acid through combined ball milling and thermal pyrolysis

Abstract Silicon and related materials have recently received considerable attention as potential anodes in Li-ion batteries for their high theoretical specific capacities. To overcome the problem of volume variations during the Li insertion/extraction process, in this work, Si/C composites with low carbon content were synthesized from cheap coarse silicon and citric acid by simple ball milling and subsequent thermal treatment. The effects of ball milling time and calcination temperature on the structure, composition and morphology of the composites were systematically investigated by the determination of specific surface area (BET) and particle-size distribution, X-ray diffraction (XRD), O2-TPO, and scanning electron microscopy (SEM). The capacity and cycling stability of the composites were systematically evaluated by electrochemical charge/discharge tests. It was found that both the initial capacity and the cycling stability of the composites were dependent on the milling and calcination conditions, and attractive overall electrochemical performance could be obtained by optimizing the synthesis process.

Nanoengineered Sn-TiC-C and Sb-MOx-C (M = Al, Ti, or Mo) Composite Anodes for Lithium-Ion Batteries

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Application of bis(fluorosulfonyl)imide-based ionic liquid electrolyte to silicon–nickel–carbon composite anode for lithium-ion batteries

An ionic liquid electrolyte containing bis(fluorosulfonyl)imide (FSI) anion without any solvent is applied to a silicon–nickel–carbon (Si–Ni–carbon) composite anode for rechargeable lithium (Li)-ion batteries. The FSI-based ionic liquid electrolyte successfully provides a stable, reversible capacity for the Si–Ni–carbon anode, which is comparable to the performance observed in a typical commercialized solvent-based electrolyte, while a common ionic liquid electrolyte containing bis(trifluoromethanesulfonyl)imide (TFSI) anion without FSI presents no reversible capacity to the anode at all. Ac impedance analysis reveals that the FSI-based electrolyte provides very low interfacial and charge-transfer resistances at the Si-based composite anode, even when compared to the corresponding resistances observed in a typical solvent-based electrolyte. Galvanostatic cycling of the Si-based composite anode in the FSI-based electrolyte with a charge limitation of 800 mAh g −1 is stable and provides a discharge capacity of 790 mAh g −1 at the 50th cycle, corresponding to a cycle efficiency of 98.8%.

Effects of electrolytes on the electrochemical performance of Si/graphite/disordered carbon composite anode for lithium-ion batteries

The influences of LiBF 4, LiClO 4, lithium bis(oxalato) borate (LiBOB), LiPF 6 with VC and without VC, and the mixed electrolytes composed of different ratios of LiBOB and LiPF 6 or LiClO 4 on the electrochemical properties of Si/graphite/disordered carbon (Si/G/DC) composite electrode were systematically investigated by constant current charge–discharge and electrochemical impedance spectra (EIS) techniques. Scanning electron microscopy (SEM) was used to observe the change of electrodes in morphology after given cycle numbers. X-ray photoelectron spectroscopy (XPS) was employed to understand the influences of different mixed electrolytes on the composition of SEI layers. The results showed that Si/G/DC composite electrode in the mixed electrolytes presented better electrochemical performance than in single electrolyte. The compactness and compositions of SEI layers intensively influenced the cycle performance of Si/G/DC composite materials. LiBOB and additive VC had a good synergistic effect on the formation of the dense SEI layers. In particular, Si/G/DC in 0.5 M LiBOB + 0.38 M LiPF 6 electrolytes containing VC exhibited a high reversible capacity and excellent cycle performance.