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1.
《Ceramics International》2017,43(12):8590-8595
To improve the electrochemical performance of silicon-based anode material, lithium fluoride (LiF) and pitch carbon were introduced to co-modify a silicon/graphite composite (SG), in which the graphite acts as a dispersion matrix. The pitch carbon helps to improve the electronic conductivity and lithium ion transport of the material. LiF is one of the main components of the solid electrolyte interphase (SEI) formed on the silicon surface, helping to tolerate the large volume changes of Si during lithiation/delithiation. The modified SG sample delivered a capacity of over 500 mA h g−1, whereas unmodified SG delivered a capacity of lower than 50 mAh g−1 after 100 cycles at 100 mA g−1. When performed at 4 A g−1, the reversible capacity of the modified SG was 346 mAh g−1, much higher than that of SG (only 37 mA h g−1). The enhanced cycling and rate properties of the modified SG can be attributed to the synergetic contribution of the pitch carbon and LiF which help accommodate the volume change, reduce the side reaction, and form a stable solid electrolyte interface layer. 相似文献
2.
Nikolay Dimov 《Electrochimica acta》2003,48(11):1579-1587
Carbon coating of silicon powder was studied as a means of preparation of silicon-based anode material for lithium ion batteries. Carbon-coated silicon has been investigated at various cycling modes vs. lithium metal. Ex situ X-ray data suggest that there is irreversible reduction of crystallinity of the silicon content. Since carbon layer preserving the integrity of the particle, the reversibility of the structural changes in the amorphous state Li-Si alloy provides the reversible capacity. The progressively decreased Coulomb efficiency with cycling indicates that more and more lithium ions are trapped in some form of Li-Si alloy and become unavailable for extraction. This is the main factor for the capacity fading during cycling. Qualitative studies of the impedance spectra of the electrode material at the first cycle for the fresh anode and at the last cycle after the anode capacity faded considerably and provide further support for this model of fading mechanism. 相似文献
3.
In situ preparation of carbon nanotubes on the surface of spherical graphite particles is made by chemical vapor deposition, resulting in an “urchin-like” hybrid material. TEM and SEM images show that carbon nanotubes are herringbone with turbulent layered structure, less than 100 nm in diameter and several micrometers in length in the average. The hybrid's use as an anode material in lithium ion batteries is examined using constant current charge-discharge tests, which prove that carbon nanotubes oriented on the surface effectively improve the reversible capacity. Cyclic voltammogram shows that there is no cathodic peak for the reaction of the Fe catalyst with Li+ in the charge-charge process in 0.0-1.6 V vs. Li/Li+ potential range. 相似文献
4.
A nano-Pt-supported carbon anode was prepared by supporting Pt nanoparticles onto carbon powder. Ultrafine Pt nanoparticles could be well distributed on the surface of carbon particles. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), FTIR, and impedance spectroscopy were used to study on the electrode structure and electrochemical performance. Nano-Pt-supported carbon anode enhanced the Li discharge reaction and suppressed the solvent decomposition reaction, which are favorable for lithium batteries. 相似文献
5.
Carbon encapsulated graphite was prepared by coating polyurea on the surface of natural graphite particles via interfacial polymerization followed by a pre-oxidation at 250 °C in air and a heat treatment at 850 °C in nitrogen. FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the structure of the graphite before and after the surface modification. Galvanostatic cycling, dc impedance spectroscopy, and cyclic voltammetry were used to investigate the electrochemical properties of the modified graphite as the anode material of lithium cells. The modified graphite shows a large improvement in electrochemical performance such as higher reversible capacity and better cycleability compared with the natural graphite. It can work stably in a PC-based electrolyte with the PC content up to 25 vol.% because the encapsulated carbon can depress the co-intercalation of solvated lithium ion. The initial coulombic efficiency of C-NG and NG in non-PC electrolyte is 74.9 and 88.5%, respectively. 相似文献
6.
Shubin Yang Haixia Yi Wenxiao Liu Huijuan Zhang Xiaohong Chen 《Electrochimica acta》2009,55(2):521-527
Carbon nanotubes capsules (CNCs) with compact, stout walls and tunable sizes were fabricated by using self-assembly of acid modified carbon nanotubes in a water-in-oil emulsion system. The effect of ultrasonic power on the formation and size of CNCs were investigated. On the basis of fabrication of CNCs, CNCs encapsulating SnO2 nanoparticles were prepared as anode material for lithium ion batteries. The morphologies, structural characteristics and electrochemical performances of CNCs and CNCs encapsulating SnO2 nanoparticles were systemically investigated by FE-SEM, TEM, XRD and a series of electrochemical testing techniques. The results showed that the encapsulation amount of SnO2 in CNCs had a great influence on the reversible capacity and cycle performance of the composites. The composite with appropriate amount of SnO2 exhibited a high reversible capacity of 383 mAh g−1 and an excellent cyclability with only 0.4% capacity loss/cycle in that CNCs not only could provide high electric conductivity for composites but also effectively accommodate the volume change of SnO2 during the cycling processes. 相似文献
7.
SnS nanoparticles were mechnochemical synthesized and then co-heated with polyvinyl alcohol (PVA) at various temperatures to obtain carbon coating. All amorphous carbon-coated SnS particles had average particle size of about 20-30 nm, revealed by transmission electron microscopy (TEM). During discharge-charge, ex situ XRD results indicated that SnS firstly decomposed to Sn, then lithium ions intercalated into Sn. The reaction of Li+ and Sn was responsible for the reversible capacity in cycling process. The lithium ion insertion and extraction mechanism of SnS anode was similar to that of Sn-based oxide. Electrochemical capacity retention of carbon-coated SnS obtained at 700 °C was superior to that of other prepared SnS anodes and especially the rate capability was obviously enhanced due to good electric conductivity and buffering matrix effects of carbon coating. 相似文献
8.
Recent studies of lithium ion batteries focus on improving electrochemical performance of electrode materials and/or lowering cost. Doping of active materials with heteroatoms is one promising method. This paper reviews the effects of heteroatoms on anode materials such as carbon- and tin-based materials, and cathode materials such as LiCoO2, LiNiO2, LiMn2O4 and V2O5. There are favorable and unfavorable effects, which depend on the species and physicochemical states of heteroatoms and the parent electrode materials. In the application of lithium ion batteries advantageous factors should be exploited, unwelcome side effects should be avoided as far as possible. Considerable gains towards improved electrochemical performance of the electrode materials have been achieved. Nevertheless, there are still problems needing further investigation including theoretical aspects, which will in the meanwhile stimulate the investigation for better electrode materials. 相似文献
9.
《Ceramics International》2017,43(14):10905-10912
Herein, a MnFe2O4/graphene (MnFe2O4/G) nanocomposite has been synthesized via a facile N2H4·H2O-induced hydrothermal method. During the synthesis, N2H4·H2O is employed to not only reduce graphene oxide to graphene, but also prevent the oxidation of Mn2+ in alkaline aqueous solution, thus ensuring the formation of MnFe2O4/G. Moreover, MnFe2O4 nanoparticles (5–20 nm) are uniformly anchored on graphene. MnFe2O4/G electrode delivers a large reversible capacity of 768 mA h g−1 at 1 A g−1 after 200 cycles and high rate capability of 517 mA h g−1 at 5 A g−1. MnFe2O4/G holds great promise as anode material in practical applications due to the outstanding electrochemical performance combined with the facile synthesis strategy. 相似文献
10.
Tin-manganese oxide film with three-dimensional (3D) reticular structure has been prepared by electrostatic spray deposition (ESD). X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate that the film is amorphous. X-ray-photoemission spectroscopy (XPS) demonstrates that the 3D grid is composed of tin-manganese oxide. As an anode electrode for the lithium ion battery, the tin-manganese oxide film has 1188.3 mAh g−1 of initial discharge capacity and very good capacity retention of 656.2 mAh g−1 up to the 30th cycle. Such a composite film can be used as an anode for lithium ion batteries with higher energy densities. 相似文献
11.
Electrochemical stability of silicon/carbon composite anode for lithium ion batteries 总被引:2,自引:0,他引:2
Silicon/carbon composite anode materials were prepared by pyrolyzing the phenol-formaldehyde resin (PFR) mixed with silicon and graphite powders. Scanning electron microscopic (SEM) observation showed that the morphology stability of the composite electrodes can be retained during cycling. A structure evolution mechanism is proposed to illuminate the enhancement of cycleability of the composite electrode. The composite used as anode material for lithium ion batteries possesses a reversible capacity of over 700 mAh/g. 相似文献
12.
Pengjian Zuo Jun Zhao Yulin Ma Xinqun Cheng Pengfei Shi Tsutomu Takamura 《Electrochimica acta》2006,52(4):1527-1531
The SiMn-graphite composite powder was prepared by mechanical ball milling and its electrochemical performances were evaluated as the candidate anode materials for lithium ion batteries. It is found that the cyclic performance of the composite materials is improved significantly compared to SiMn alloy and pure silicon. The heat treatment of the electrodes is beneficial for enhancing the cyclic stabilities. The SiMn-20 wt.% graphite composite electrode after annealing at 200 °C has an initial reversible capacity of 463 mAh g−1 and a charge-discharge efficiency of 70%. Moreover, the reversible capacity maintains 426 mAh g−1 after 30 cycles with a coulomb efficiency of over 97%. The phase structure and morphology of the composite were analyzed by X-ray diffraction (XRD) and scanning electron microscopy. The lithiation/delithiation behavior was investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The composite materials appear to be promising candidates as negative electrodes for lithium rechargeable batteries. 相似文献
13.
Composite silicon film, which is composed of silicon nanowires, Si-Au eutectic and Si particles as the melding spots, was prepared as anode for lithium ion batteries by a special secondary deposition process with vapor-liquid-solid (VLS) mechanism. Au-Si eutectic particles act as the melding spots between silicon nanowires. An attractive electrochemical performance with 88% of the coulombic efficiency in the first cycle was obtained in the charge-discharge tests. The connection among silicon nanowires by dispersed Si-Au particles is the key factor for the enhancement of its electrochemical reversibility. 相似文献
14.
A sol–gel based route was used to produce TiO2 based nanocomposites. Sols were electrospun into continuous nanofibers and calcined to get rutile phase. Fibers with diameter around 100 nm and crystallites size between 10 and 50 nm were obtained. The morphological impact and crystallites size dependence of the electrochemical performance for as-synthesized materials are reported. Enhancements using inert calcination atmosphere and incorporation of multi-wall carbon nanotubes (MWCNT) into the system are also presented. 相似文献
15.
We synthesize a carbon anode material with unique nanostructure for high power lithium ion batteries. The carbon material is composed of numerous clusters of carbon nanobeads, and shows a macro-meso-micro hierarchical porous structure. This unique nanostructure appears to facilitate the rapid transfer of lithium ions and a very large ion adsorption. It exhibits a reversible capacity of 407.4 mAh g−1 and its rate performance is drastically improved in comparison with that of the commercial graphite. The unique structure enables the anode to combine the advantages of both lithium ion batteries and electrochemical double layer capacitors, resulting in the good electrochemical performance. 相似文献
16.
Rui-an Huang Yuzhong Guo Zhining Chen Xingshuai Zhang Jianhua Wang Bin Yang 《Ceramics International》2018,44(4):4282-4286
A new three-dimensional (3D) sandwich-like Si/Polyaniline/Graphene nanoarchitecture anode for lithium ion batteries (LIBs) is successfully fabricated through an easy approach. In this nanoarchitecture, the in-situ polymerized electronic conductive polyaniline (PAni) hydrogel, acting as “glue”, agglutinates tightly to both the silicon nanoparticles (SiNPs) and graphene sheets, forming efficient conductive networks with high elastic modulus and high tensile strength. This mechanically robust nanoarchitecture can endure the great volume change of silicon and retain structural stability during Li-ion insertion/extraction. The electrodes consisting of this 3D sandwich-like Si/Polyaniline/Graphene nanoarchitecture reveal excellent electrochemical performance. The progress made in this work provides an easy and scalable route for preparing Si-based anode materials with high performance for advanced LIBs. 相似文献
17.
SnO2/multi-walled carbon nanotube (MWCNT) composites were prepared by the solvothermal method and subsequent heat treatment at 360 °C. The samples were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Results on the higher SnO2 content composite sample indicate that a uniform layer of SnO2 nanocrystals with crystal size around 5 nm was deposited on the surface of the carbon nanotubes. The composite demonstrates a reversible lithium storage capacity of 709.9 mAh g−1 at the first cycle and excellent cyclic retention up to 100 cycles as anode for lithium ion batteries. 相似文献
18.
Jie Zhang Ruixia Chu Yanli Chen Heng Jiang Ying Zhang Nay Ming Huang Hang Guo 《Ceramics International》2018,44(14):16219-16226
Nickle foam-supported hierarchical ZnCo2O4 nanosheets was prepared via a facile solution-based method. Porous ZnCo2O4 nanosheets were in-situ grown on current collector, forming a binder-free electrode. When evaluated as anode for Lithium ion batteries (LIBS), the binder-free electrode showed an attractive electrochemical performance. A reversible capacity of 773?mAh?g?1 could be stably delivered after a 500-cycle test at a current density of 0.25?A?g?1, with a high capacity retention of 87%. The electrode could maintain a high reversible capacity of 245?mA?h?g?1 even at an elevated current density of 8.0?A?g?1. Integrated structure and rich porosity of the binder-free electrode were believed to contribute to the superior performance. Thus, the Nickle foam-supported ZnCo2O4 electrode is a promising anode for high performance LIBs in the coming future. 相似文献
19.
The reasonable structure construction of electrode materials with superior performance is desired for the new generation lithium ion batteries (LIBs). Herein, binder-free multilayered SnO2/graphene (GN) on Ni foam was fabricated via a dip coating method. SnO2 nanoparticles and GN were alternatively coated on Ni foam to form a sandwich-like structure. The wrapping of GN can raise the conductivity and keep the structural integrality of the binder-free material, preventing structure collapse arised from the volume expansion of SnO2. Benefiting from the porous Ni foam framework and sandwich-like structure, the SnO2/GN composite exhibited good rate performance and excellent cycle stability. High capacities of 708 and 609?mAh?g?1 were achieved at rates of 1 and 2?A?g?1. Besides, the SnO2/GN electrode delivered a high capacity of 757?mAh?g?1 after 500 cycles at 1?A?g?1. 相似文献
20.
Natural graphite (NG) was sulfurized by heat-treating or by high energy ball-milling the blend of NG with sulfur powder. The effect of the surface functional groups, containing sulfur, on the performance of the NG anode for a lithium ion battery was then investigated. X-ray photoelectron spectroscopy revealed that the sulfur was introduced onto the surface of NG in both of these methods. The results of scanning electron microscopy and Raman spectroscopy showed that the surface disorder of NG increased after sulfurization. Charge/discharge tests showed that the reversible capacity of the first cycle was increased after surface sulfurization and that the coulombic efficiency of the first cycle increased for the heat-treated sample but decreased for the ball-milled one. The change in the electrochemical performance was due to a number of factors including an increase in new active sites for lithium storage and an increase in surface area and increased disorder of the sulfurized NG samples. 相似文献