共查询到20条相似文献,搜索用时 375 毫秒
1.
T. L. Kulova Yu. V. Pleskov A. M. Skundin E. I. Terukov O. I. Kon’kov 《Russian Journal of Electrochemistry》2006,42(7):708-714
Lithium intercalation into 0.25-μm-thick films of amorphous silicon is studied using the electrochemical-impedance technique. An equivalent circuit, proposed for such electrodes, comprises the electrolyte resistance and three units connected in series, each unit being a parallel combination of a resistance and a constant-phase element. The units relate to the charge transfer processes at the silicon/electrolyte interface, charge transfer though the passive film on the silicon, and the lithium diffusion into the silicon bulk. During potential cycling, changes occur largely in the unit related to the passive film. The lithium diffusion coefficient in the amorphous silicon is estimated as ~ 10?13 cm2 s?1. 相似文献
2.
T. L. Kulova N. F. Nikol’skaya A. M. Skundin 《Russian Journal of Electrochemistry》2008,44(5):558-563
Comparative studies of three type of carbonaceous materials—the modified oxidized graphite, thermoexpanded graphite, and carbon paper—prior to and after galvanostatic cycling in 1 M LiClO4 solution in propylene carbonate-dimethoxyethane mixture are carried out using standard porosimetry. It was shown that the mean (effective) thickness of the passive film [solid electrolyte interface (SEI)] at the electrodes of the modified oxidized graphite and thermoexpanded graphite equals a few nanometers. The comparison of porosimetric and electrochemical data shows that the passive film comprises both lithium carbonate and alkylcarbonates. Additionally, this comparison allows corroborating the concept on the formation of polymer (or oligomer) component of the passive film at least at the thermoexpanded graphite electrodes. 相似文献
3.
S. P. Kuksenko 《Russian Journal of Electrochemistry》2013,49(1):67-75
Aluminum is used as an example to demonstrate the possibility of spatial stabilization of alloy-forming electrodes of lithium-ion batteries using target formation on their surface of a thin compact inorganic layer and elastic organopolymer coating of products of electroreduction of electrolyte components for improvement of capacity retention and suppression of processes corresponding to irreversible capacity. It is suggested to use aluminum foil as a convenient material and the general approach can be employed as a methodological technique for accelerated composition of an acceptable electrolyte formula for electrodes containing other elements forming alloys with lithium (in particular, silicon and tin). 相似文献
4.
T. L. Kulova 《Russian Journal of Electrochemistry》2011,47(8):965-967
The minimal irreversible capacity of negative electrodes of lithium-ion batteries, necessary for their stable operation, is
theoretically evaluated. The theoretical values are compared with real ones reported in literature. It is shown that the real
values of the irreversible capacity for electrodes made of carbonaceous materials exceed several times the minimal required
values; the real irreversible capacity of silicon-based electrodes exceeds the minimal values by 2 to 3 orders of magnitude. 相似文献
5.
The feasibility of reducing the irreversible capacity of negative graphite electrodes in lithium-ion batteries by a direct contact of such electrodes with lithium in the electrolyte is studied. It is shown that the dynamics of the formation of the passive film on graphite and the degree of the decrease in the irreversible capacity depend on the ratio between weights of graphite and lithium in contact. This method of reducing the irreversible capacity does not diminish the reversible capacity of graphite during the cycling. The irreversible capacity of the initial graphite cycled in 1 M LiPF6 in a mixture of propylene carbonate and diethyl carbonate at a current density of 20 mA g–1 is 550–1150 mA h g–1. The reversible capacity of electrodes cycled in the same conditions reaches 290 mA h g–1. 相似文献
6.
Yu. E. Roginskaya T. L. Kulova A. M. Skundin M. A. Bruk E. N. Zhikharev V. A. Kal’nov 《Russian Journal of Electrochemistry》2008,44(9):992-1001
Using the method of magnetron-plasma sputtering of polycrystalline silicon target, amorphous silicon films 32–214 nm thick were produced on various (copper and titanium, polished and rough) substrates. A study of their charge-discharge characteristics under the galvanostatic conditions showed that all thin-filmed electrodes are capable of reversible lithium insertion. The amount of lithium inserted in the first cycles is close to the theoretical one. An analysis of composition and morphology of surface layer and also the behavior of reversible and irreversible capacities during cycling showed that the degradation of capacity is caused by the exfoliation of films from the substrate (the effect is more pronounced for the specimens with polished substrates) and somewhat breaking (cracking) of films. The thicker are the films, the severer is the disruption of silicon films in the cycling. The adhesion of films to the substrate surface is favored by the film roughness. At sufficiently high adhesion of films, their electrochemical properties only slightly depend on the nature (copper or titanium) of substrate. 相似文献
7.
《Electrochemistry communications》2007,9(4):796-800
High lithiation capacity at low red-ox potentials in combination with good safety characteristics makes amorphous Si as a very promising anode material for rechargeable Li batteries.Thin film silicon electrodes were prepared by DC magnetron sputtering of silicon on stainless steel substrates. Their behavior as Li insertion/extraction electrodes was studied by voltammetry and chronopotentiometry at room temperature in the ionic liquid (IL) 1-methyl-1-propylpiperidinium bis(trifluoromethylsuphonil)imide containing 1 M Li bis(trifluoromethylsuphonil)imide. Li/Si cells containing this electrolyte showed good performance with a stable Si electrodes capacity of about 3000 mA h g−1 and a relatively low irreversible capacity. Preliminary results on cycling Si–LiCoO2 cells using this IL electrolyte are also presented. 相似文献
8.
E. E. Coral-Escobar M. A. Pech-Canul M. I. Pech-Canul 《Journal of Solid State Electrochemistry》2010,14(5):803-810
The anodic polarization behavior of alloy Al–17Si–14Mg in borate solutions with and without 0.01 M NaCl was compared to that
for pure Al. Results showed that, for the alloy, the passive current density increased but the pitting susceptibility decreased.
The first effect was ascribed to a significant electrochemical activity of the Mg2Si intermetallics and the second to improved stability of the oxide film. X-ray photoelectron spectroscopy analysis of potentiostatically
formed passive film on the alloy showed that it consisted of aluminum oxyhydroxide with incorporation of silicon in its elemental
and two oxidized states (+3 and +4). Mott–Schottky analysis showed that trivalent silicon ion acted as an n-type dopant in
the film. The interrelationship between passive film composition, electronic properties, and pitting behavior has been discussed. 相似文献
9.
T. L. Kulova A. M. Skundin A. D. Shepelev T. Kh. Tenchurin Yu. E. Roginskaya 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(12):2222-2226
Pyrolized Si/C composite fibers and films were studied in the processes of lithium intercalation-extraction during the operation
of rechargeable lithium-ion batteries and supercapacitors. It was found that their electrochemical characteristics differ
from those of pure silicon and pure carbon. Analysis of these parameters under charge-discharge conditions allowed us to determine
the optimum composition of precursors: FM-1 and TEOS mixtures used as silicon-containing components. The optimum modes and
temperatures of fiber pyrolysis were found to have a Si/C ratio of 3/2 in the pyrolyzed fibers and an oxygen content not much
greater than 20 at %. The prospects for applying fibers in the form of film electrodes (the best stability in cycling) and
adhesives with developed structural networks are shown. 相似文献
10.
A method of elimination of the amorphous silicon irreversible capacity is suggested, which is based on the direct contact
of the silicon and lithium metal under electrolyte. It is shown that this contact yields a solid-electrolyte film over the
electrode surface even prior to its initial cathodic polarization, which results in the elimination of the irreversible capacity
of amorphous silicon. 相似文献
11.
A.M. Bond 《Analytica chimica acta》1975,74(1):163-175
Linear-sweep and stripping a.c. and pulse voltammetric methods have been compared for a variety of electrodes and electrode processes. Each of the linear-sweep techniques is readily used systematically because, in contrast to d.c. linear-sweep voltammetry, the theory for reversible electrode processes is basically analogous to that for polarography at a dropping mercury electrode. In stripping analysis, some departures are found at a hanging mercury drop electrode because of spherical diffusion effects. For reversible electrode processes, the limits of detection for a.c. and pulse methods are comparable. However, a.c. methods offer advantages over pulse methods in discriminating against irreversible electrode processes and permit the ready use of faster scan rates. Pulse methods are more sensitive for irreversible electrode process. Normal pulse polarography is particularly favourable in minimizing undesirable phenomena arising from adsorption or deposition of material on electrodes. 相似文献
12.
Energy Storage Materials from Nature through Nanotechnology: A Sustainable Route from Reed Plants to a Silicon Anode for Lithium‐Ion Batteries
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Dr. Jun Liu Peter Kopold Prof. Peter A. van Aken Prof. Joachim Maier Prof. Yan Yu 《Angewandte Chemie (International ed. in English)》2015,54(33):9632-9636
Silicon is an attractive anode material in energy storage devices, as it has a ten times higher theoretical capacity than its state‐of‐art carbonaceous counterpart. However, the common process to synthesize silicon nanostructured electrodes is complex, costly, and energy‐intensive. Three‐dimensional (3D) porous silicon‐based anode materials have been fabricated from natural reed leaves by calcination and magnesiothermic reduction. This sustainable and highly abundant silica source allows for facile production of 3D porous silicon with very good electrochemical performance. The obtained silicon anode retains the 3D hierarchical architecture of the reed leaf. Impurity leaching and gas release during the fabrication process leads to an interconnected porosity and the reductive treatment to an inside carbon coating. Such anodes show a remarkable Li‐ion storage performance: even after 4000 cycles and at a rate of 10 C, a specific capacity of 420 mA h g?1 is achieved. 相似文献
13.
S. A. Zavyalov T. L. Kulova L. Yu. Kupriyanov Yu. E. Roginskaya A. M. Skundin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(13):2165-2168
New film materials for electrodes of lithium batteries were synthesized and studied. Thin-film silicon-polymer composites
were prepared by vacuum cocondensation of silicon and the monomer onto a substrate cooled with liquid nitrogen; the polymerization
and formation of the nanostructured composite were performed at room temperature. The films were carbonized by vacuum annealing.
The film composition and microstructure were studied by AFM, SEM, Raman spectroscopy, and X-ray spectral microanalysis. It
was shown that the polymer matrix became almost fully carbonized because of pyrolysis. The silicon concentration in the films
varied from 2 to 5 at %. The concentration of silicon nanoparticles on carbonized film surfaces was ∼106 cm−2. Electrochemical experiments with lithium insertion into the composite films were performed in standard three-electrode cells
under galvanostatic conditions. The specific capacitance of the films was measured. It was shown that the samples were capable
of long-term cycling; the capacitance decreased by only 6% during the first 200 cycles; after 250 cycles, the capacitance
still exceeded 80% of its initial value. The mechanism of lithium insertion into the films was discussed. It was concluded
that long-term stability during cycling was caused by the presence of silicon both as nanoparticles and in the atomically
dispersed form. 相似文献
14.
Cycling parameters (reversible specific capacity, first-cycle coulombic efficiency, accumulated irreversible capacity, and
reversible capacity retention) of hybrid electrodes based on mechanical mixtures of a silicon nanopowder with KS6 and MAG-20
synthetic graphites and binders of varied nature were subjected to an integrated analysis in comparison with graphite electrodes. 相似文献
15.
Stuart M. Macdonald Katarzyna Szot Joanna Niedziolka Frank Marken Marcin Opallo 《Journal of Solid State Electrochemistry》2008,12(3):287-293
A hydrophilic carbon nanoparticle–sol-gel electrode with good electrical conductivity within the sol-gel matrix is prepared.
Sulfonated carbon nanoparticles with high hydrophilicity and of 10–20 nm diameter (Emperor 2000) are co-deposited onto tin-doped
indium oxide substrates employing a sol-gel technique. The resulting carbon nanoparticle-sol-gel composite electrodes are
characterized as a function of composition and salt (KCl) additive. Scanning electron microscopy and voltammetry in the absence
and in the presence of a solution redox system suggest that the composite electrode films can be made electrically conducting
and highly porous to promote electron transport and transfer. The effect of the presence of hydrophilic carbon nanoparticles
is explored for the following processes: (1) double layer charging, (2) diffusion and adsorption of the electrochemically
reversible solution redox system 1,1′-ferrocenedimethanol, (3) electron transfer to the electrochemically irreversible redox
system hydrogen peroxide, and (4) electron transfer to the redox liquid tert-butylferrocene deposited into the porous composite
electrode film. The extended electrochemically active hydrophilic surface area is beneficial in particular for surface sensitive
processes (1) and (3), and it provides an extended solid|organic liquid|aqueous solution boundary for reaction (4). The carbon
nanoparticle–sol-gel composite electrodes are optimized to provide good electrical conductivity and to remain stable during
electrochemical investigation. 相似文献
16.
锡钴合金电沉积层的结构与锂离子嵌脱行为 总被引:4,自引:0,他引:4
应用电沉积方法制备Sn-Co合金镀层.X-射线衍射和扫描电子显微镜分析表明,该Sn-Co合金镀层为六方固溶体结构,含Co量为20%的Sn-Co合金,其沉积层呈现(110)择优取向.表面微孔随沉积层Co含量的增加而增多.以Sn-Co合金镀层作锂离子电极材料,电化学性能测试表明,其首次充电曲线表现出锡钴合金、锡及锡氧化物与锂合金化的多个反应综合特征,随后的充电曲线趋于稳定,呈现L i-Sn-Co合金化反应特征;具有择优取向和多孔结构的Sn-Co合金电极材料的充放电性能较好,首次库仑效率为63.9%,经过20次充放电循环后,其充电容量为461mAg/h,库仑效率为99%. 相似文献
17.
V. S. Dubasova V. A. Mikhailova A. F. Nikolenko T. A. Ponomareva T. Yu. Smirnova V. F. Pleshakov 《Russian Journal of Electrochemistry》2013,49(2):161-175
The effect of structural and surface properties of carbon anodic materials based on natural graphite of the Taiginka Deposit obtained using different technologies on the capacity characteristics of the negative electrode of a lithium-ion battery is studied. It is shown that the key factors determining the value of irreversible capacity of the negative electrode in the first cycle are the value of graphite specific surface area, the state of the surface, in particular, the content of disordered carbon, and functional groups on the surface of graphite particles, and also the composition of the active electrode layer. A change in the specific surface area value and content of functional groups is due to the efficiency of the pyrocarbon coating in the case of samples subjected to milling on vibration and cavitation mills, and also of finely dispersed samples obtained by milling on a jet mill. The observed decrease in the specific surface irreversible capacity at an increase in the specific surface area of carbon is apparently caused by inhomogeneity of the latter and nonparticipation of its microporous part in formation of the solid-phase surface passivating film. The minimum irreversible specific capacity of electrodes of the studied natural graphite for the optimum electrode material composition was about 20 mA h/g or 6%. The specific surface capacity changed as dependent on the value and state of the graphite sample surface more than threefold (from 2.5 to 7.7 mA h/m2) and by an order of magnitude at an additional change in the electrode composition (from 2.5 to 20.3 mA h/m2). 相似文献
18.
19.
本文研究了在LiFSI-(PC)3高浓度电解液中添加剂对于纳米硅材料的循环性能的影响,采用扫描电子显微镜、傅里叶变换红外光谱和X-射线光电子能谱分析了循环过程纳米硅材料及其电极的结构和表面SEI膜演化的特征. 结果表明,添加剂能够改善纳米硅材料的循环性能,在LiFSI-(PC)3高浓度电解液中循环300周材料比容量为574.8 mAh·g-1,而含有3%LiDFOB、3%FEC、3%TMSB的添加剂的高浓度电解液中,比容量分别为1142.9、1863.6和1852.2 mAh·g-1. 作者分析认为,在LiFSI-(PC)3浓溶液中LiFSI优先于PC在纳米硅表面发生成膜反应,形成的SEI膜由以无机物主导的内层膜和以有机物主导的外层膜组成,而在含添加剂的高浓度电解液中,添加剂和LiFSI协同参与SEI成膜反应,形成的内层膜能够减缓PC溶剂参与外层的成膜反应,由此形成的SEI膜能够抑制循环过程中SEI膜的过度生长,更好地抑制了纳米硅的粉化,纳米硅材料及其电极结构稳定性更好,材料表现出更好的循环性能. 相似文献
20.
Mercury-thin film electrodes coated with a thin film of poly(ester sulphonic acid) (PESA) have been investigated for application in the analysis of trace heavy metals by square wave anodic stripping voltammetry using the batch injection analysis (BIA) technique. Different polymer dispersion concentrations in water/acetone mixed solvent are investigated and are characterised by electrochemical impedance measurements on glassy carbon and on mercury film electrodes. The influence of electrolyte anion, acetate or nitrate, on polymer film properties is demonstrated, acetate buffer being shown to be preferable for stripping voltammetry applications. Although stripping currents are between 30 and 70% less at the coated than at bare mercury thin film electrodes, the influence of model surfactants on stripping response is shown to be very small. The effect of the composition of the modifier film dispersion on calibration plots is shown; however, detection limits of around 5 nM are found for all modified electrodes tested. This coated electrode is an alternative to Nafion-coated mercury thin film electrodes for the analysis of trace metals in complex matrices, particularly useful when there is a high concentration of non-ionic detergents. 相似文献