共查询到20条相似文献,搜索用时 31 毫秒
1.
E. Shembel R. Apostolova I. Kirsanova V. Tysyachny 《Journal of Solid State Electrochemistry》2008,12(9):1151-1157
The active molybdenum sulfide compound Mo2S3, which should be considered as a cathode material for thin-layer rechargeable power source, has been produced by electrolysis.
Using impedance spectroscopy and potential relaxation method after current interruption, the kinetic parameters of lithium
intercalation in electrolytic Mo2S3 have been obtained. Activation energy of Li+ migration in electrolyte (13.76 kJ/mol), charge transfer through the Mo2S3 electrode/electrolyte interface (38.8 kJ/mol), and Li+ diffusion in a solid phase (57.3 kJ/mol) have also been established. Taking into account the coefficient data of charge mass
transfer in a solid phase and the reaction rate coefficient of charge transfer through the interface electrode/electrolyte
within the temperature range 20–50 °C, the stage of Li+ transfer in a solid phase has been determined as a limiting stage for lithium intercalation in electrolytic molybdenum sulfide
Mo2S3. 相似文献
2.
Yu. V. Baskakova O. V. Yarmolenko N. I. Shuvalova G. Z. Tulibaeva O. N. Efimov 《Russian Journal of Electrochemistry》2006,42(9):949-953
The effect of 15-crown-5, which is applied immediately to pure and modified surface of a lithium electrode, on the charge transfer resistance at the electrode/polymer electrolyte interface is studied. The polymer electrolyte consists of a 1: 1 mixture of oligourethan dimethacrylate and polypropylene glycol monomethacrylate (20 wt %), an initiator (azobisisobutyronitrile) (2 wt %), and a 1 M LiClO4 solution in gamma-butyrolactone (78 wt %). The conductivity of this gel electrolyte is 3 × 10?3 S cm?1. The temperature dependence of the impedance of the Li/gel electrolyte/Li electrochemical cells is measured for electrodes of four types. The activation energies for the charge transfer at the Li/electrolyte interface are calculated. It is found that, after treating the test lithium electrodes with 15-crown-5, the charge transfer resistance decreases, and in the case of the modified lithium surface, the activation energy for the process decreases by 1.8 times. 相似文献
3.
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
4.
Sr0.25Bi0.5FeO3–
δ (SBF) has been studied as a cathode material for low- and intermediate-temperature (600–850 °C) solid oxide fuel cells (SOFCs)
based on the La0.9Sr0.1Ga0.9Mg0.1O3 (LSGM) electrolyte. The observed cathodic current density passing through an SBF/LSGM interface at 840 °C in pure oxygen is
about 1 A·cm–2 at an overpotential of 40 mV, much higher than that for an LaxSr1–xMnO3 electrode under similar conditions reported in the literature. Analysis indicates that the electrode kinetics is controlled
primarily by mass transfer at high temperatures and by charge transfer at low temperatures. The inductive loops of the impedance
spectra further suggest that the adsorption of intermediate species is involved in the interfacial reaction.
Electronic Publication 相似文献
5.
Single‐Nanoparticle Collision Events: Tunneling Electron Transfer on a Titanium Dioxide Passivated n‐Silicon Electrode
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Dr. Hyun S. Ahn Prof. Allen J. Bard 《Angewandte Chemie (International ed. in English)》2015,54(46):13753-13757
Single‐nanoparticle collisions were observed on an n‐type silicon electrode (600 μm diameter) passivated by a thin layer of amorphous TiO2, where the current steps occurred by tunneling electron transfer. The observed collision frequency was in reasonable agreement with that predicted from theory. The isolated electrode, after a collision experiment, with a Pt/TiO2/n‐Si architecture was shown to retain the photoelectrochemical properties of n‐Si without photocorrosion or current decay. The Pt/TiO2/n‐Si electrode produced 19 mA cm?2 of photocurrent density under 100 mW cm?2 irradiation from a xenon lamp during oxygen evolution without current fading for over 12 h. 相似文献
6.
Electrochemical reduction of oxygen at the interface between a La0.9Sr0.1MnO3 (LSM)-based electrode and an electrolyte, either yttria-stabilized-zirconia (YSZ) or La0.8Sr0.2Ga0.9Mg0.1O3 (LSGM), has been investigated using DC polarization, impedance spectroscopy, and potential step methods at temperatures from
1053 to 1173 K. Results show that the mechanism of oxygen reduction at an LSM/electrolyte interface changes with the type
of electrolyte. At an LSM/YSZ interface, the apparent cathodic charge transfer coefficient is about 1 at high temperatures,
implying that the rate-determining step (r.d.s.) is the diffusion of partially reduced oxygen species, while at an LSM/LSGM
interface the cathodic charge transfer coefficient is about 0.5, implying that the r.d.s. is the donation of electrons to
atomic oxygen. The relaxation behavior of the LSM/electrolyte interfaces displays an even more dramatic dependence on the
type of electrolyte. Under cathodic polarization, the current passing through an LSM/YSZ interface increases with time whereas
that through an LSM/LSGM interface decreases with time, further confirming that it is the triple phase boundaries (TPBs),
rather than the surface of the LSM or the LSM/gas interface, that dominate the electrode kinetics when LSM is used as an electrode.
Electronic Publication 相似文献
7.
Xingming Ning Bingzhang Lu Zhen Zhang Peiyao Du Hongxia Ren Duoliang Shan Jing Chen Yunjing Gao Xiaoquan Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):16956-16961
Surface recombination at the photoanode/electrolyte junction seriously impedes photoelectrochemical (PEC) performance. Through coating of photoanodes with oxygen evolution catalysts, the photocurrent can be enhanced; however, current systems for water splitting still suffer from high recombination. We describe herein a novel charge transfer system designed with BiVO4 as a prototype. In this system, porphyrins act as an interfacial‐charge‐transfer mediator, like a volleyball setter, to efficiently suppress surface recombination through higher hole‐transfer kinetics rather than as a traditional photosensitizer. Furthermore, we found that the introduction of a “setter” can ensure a long lifetime of charge carriers at the photoanode/electrolyte interface. This simple interface charge‐modulation system exhibits increased photocurrent density from 0.68 to 4.75 mA cm?2 and provides a promising design strategy for efficient photogenerated charge separation to improve PEC performance. 相似文献
8.
The effects of Co alloying to Pt catalyst and Nafion pretreatment by NaClO4 solution on the rate-determining step (RDS) of oxygen reduction at Nafion-impregnated Pt-dispersed carbon (Pt/C) electrode
were investigated as a function of the potential step ΔE employing potentiostatic current transient (PCT) technique. For this purpose, the cathodic PCTs were measured on the pure
Nafion-impregnated and partially Na+-doped Nafion-impregnated Pt/C and PtCo/C electrodes in an oxygen-saturated 1 M H2SO4 solution and analyzed. From the shape of the cathodic PCTs and the dependence of the instantaneous current on the value of
ΔE, it was confirmed that oxygen reduction at the pure Nafion-impregnated electrodes is controlled by charge transfer at the
electrode surface mixed with oxygen diffusion in the solution below the transition potential step |ΔE
tr| in absolute value, whereas oxygen reduction is purely governed by oxygen diffusion above |ΔE
tr|. On the other hand, the RDS of oxygen reduction at the partially Na+-doped Nafion-impregnated electrodes below |ΔE
tr| is charge transfer coupled with proton migration, whereas above |ΔE
tr|, it becomes proton migration in the Nafion electrolyte instead of oxygen diffusion. Consequently, it is expected in real
fuel cell system that the cell performance is improved by Co alloying since the electrode reaches the maximum diffusion (migration)
current even at small value of |ΔE|, whereas the cell performance is aggravated by Nafion pretreatment due to the decrease in the maximum diffusion (migration)
current. 相似文献
9.
Yong Gao Dani Zhang Dr. Jingjing Li Prof. Hao Gong Dr. Cheng Jiang Dr. Hairong Xue Prof. Xianli Huang Prof. Tao Wang Prof. Jianping He 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(71):e202202410
Electrocatalysis is the most promising strategy to generate clean energy H2, and the development of catalysts with excellent hydrogen evolution reaction (HER) performance at high current density that can resist strong alkaline and acidic electrolyte environment is of great significance for practical industrial application. Therefore, a P doped MoS2@Ni3S2 nanorods array (named P-NiMoS) was successfully synthesized through successive sulfuration and phosphorization. P-NiMoS presents a core/shell structure with a heterojunction between MoS2 (shell) and Ni3S2 (core). Furthermore, the doping of P modulates the electronic structure of the P-NiMoS; the electrons transfer from the t2g orbital of Ni element to the eg empty orbital of Mo element through the Ni−S−Mo bond at the Ni3S2 and MoS2 heterojunction, facilitating the hydrogen evolution reaction. As a result, P-NiMoS exhibits excellent HER activity; the overpotential is 290 mV at high current density of 250 mA cm−2 in alkaline electrolyte, which is close to Pt/C (282 mV@250 mA cm−2), and P-NiMoS can stably evolve hydrogen for 48 h. 相似文献
10.
Enhanced Electrocatalytic Performance of a Porous g‐C3N4/Graphene Composite as a Counter Electrode for Dye‐Sensitized Solar Cells
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Prof. Guiqiang Wang Dr. Juan Zhang Dr. Shuai Kuang Dr. Wei Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11763-11769
A porous graphitic carbon nitride (g‐C3N4)/graphene composite was prepared by a simple hydrothermal method and explored as the counter electrode of dye‐sensitized solar cells (DSCs). The obtained g‐C3N4/graphene composite was characterized by XRD, SEM, TEM, FTIR spectroscopy, and X‐ray photoelectron spectroscopy. The results show that incorporating graphene nanosheets into g‐C3N4 forms a three‐dimensional architecture with a high surface area, porous structure, efficient electron‐transport network, and fast charge‐transfer kinetics at the g‐C3N4/graphene interfaces. These properties result in more electrocatalytic active sites and facilitate electrolyte diffusion and electron transport in the porous framework. As a result, the as‐prepared porous g‐C3N4/graphene composite exhibits an excellent electrocatalytic activity. In I?/I3? redox electrolyte, the charge‐transfer resistance of the porous g‐C3N4/graphene composite electrode is 1.8 Ω cm2, which is much lower than those of individual g‐C3N4 (70.1 Ω cm2) and graphene (32.4 Ω cm2) electrodes. This enhanced electrocatalytic performance is beneficial for improving the photovoltaic performance of DSCs. By employing the porous g‐C3N4/graphene composite as the counter electrode, the DSC achieves a conversion efficiency of 7.13 %. This efficiency is comparable to 7.37 % for a cell with a platinum counter electrode. 相似文献
11.
Jessica J. Hong Liangdong Zhu Cheng Chen Longteng Tang Heng Jiang Bei Jin Trenton C. Gallagher Qiubo Guo Chong Fang Xiulei Ji 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):16057-16062
Plating battery electrodes typically deliver higher specific capacity values than insertion or conversion electrodes because the ion charge carriers represent the sole electrode active mass, and a host electrode is unnecessary. However, reversible plating electrodes are rare for electronically insulating nonmetals. Now, a highly reversible iodine plating cathode is presented that operates on the redox couples of I2/[ZnIx(OH2)4?x]2?x in a water‐in‐salt electrolyte. The iodine plating cathode with the theoretical capacity of 211 mAh g?1 plates on carbon fiber paper as the current collector, delivering a large areal capacity of 4 mAh cm?2. Tunable femtosecond stimulated Raman spectroscopy coupled with DFT calculations elucidate a series of [ZnIx(OH2)4?x]2?x superhalide ions serving as iodide vehicles in the electrolyte, which eliminates most free iodide ions, thus preventing the consequent dissolution of the cathode‐plated iodine as triiodides. 相似文献
12.
Enhancing Capacity Performance by Utilizing the Redox Chemistry of the Electrolyte in a Dual‐Electrolyte Sodium‐Ion Battery
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Dr. Sirugaloor Thangavel Senthilkumar Hyuntae Bae Jinhyup Han Prof. Youngsik Kim 《Angewandte Chemie (International ed. in English)》2018,57(19):5335-5339
A strategy is described to increase charge storage in a dual electrolyte Na‐ion battery (DESIB) by combining the redox chemistry of the electrolyte with a Na+ ion de‐insertion/insertion cathode. Conventional electrolytes do not contribute to charge storage in battery systems, but redox‐active electrolytes augment this property via charge transfer reactions at the electrode–electrolyte interface. The capacity of the cathode combined with that provided by the electrolyte redox reaction thus increases overall charge storage. An aqueous sodium hexacyanoferrate (Na4Fe(CN)6) solution is employed as the redox‐active electrolyte (Na‐FC) and sodium nickel Prussian blue (Nax‐NiBP) as the Na+ ion insertion/de‐insertion cathode. The capacity of DESIB with Na‐FC electrolyte is twice that of a battery using a conventional (Na2SO4) electrolyte. The use of redox‐active electrolytes in batteries of any kind is an efficient and scalable approach to develop advanced high‐energy‐density storage systems. 相似文献
13.
It is shown that the charge dependence of the difference between reciprocal differential capacitances for two La2(SO4)3concentrations at the same charge qreliably reveals that properties of the diffuse layer at |q| of 1 to 2 C/cm2are not ideal. Experimental values of the capacitance of Hg, Tl–Ga, and Cd–Ga electrodes in La2(SO4)3aqueous solutions suggest that this phenomenon is adequately described by the Gonzalez–Sanz theory, which links activity coefficients of ions in the diffuse layer with the average stoichiometric activity coefficient in the electrolyte and the electrode charge. 相似文献
14.
We report the fabrication of an ultra-thin silicon oxynitride (SiON) as an interfacial layer (IL) for n-Si/ALD-HfO2 gate stack with reduced leakage current. The XRD, AFM, FTIR, FESEM and EDAX characterizations have been performed for structural and morphological studies. Electrical parameters such as dielectric constant (K), interface trap density (Dit), leakage current density (J), effective oxide charge (Qeff), barrier height (Φbo), ideality factor (ƞ), breakdown-voltage (Vbr) and series resistance (Rs) were extracted through C-V, G-V and I-V measurements. The determined values of K, Dit, J, Qeff, Φbo, ƞ, Vbr and Rs are 14.4, 0.5 × 10 11 eV−1 cm−2, 2.2 × 10−9 A/cm2, 0.3 × 1013 cm−2, 0.42, 2.1, −0.33 and 14.5 MΩ respectively. SiON growth prior to HfO2 deposition has curtailed the problem of high leakage current density and interfacial traps due to sufficient amount of N2 incorporated at the interface. 相似文献
15.
M. Chatelut S. Chah-Bouzziri O. Vittori A. Benayada 《Journal of Solid State Electrochemistry》2000,4(8):435-443
A lead electrode was studied in 6 and 12 M H3PO4. Oxidation of a freshly polished electrode occurred in the −0.5 to −0.3 V vs. SCE range, and led to PbHPO4 growth on the electrode surface. The dissolution of this layer by electrochemical reduction occurred between −0.5 and −0.7 V.
The influence of temperature (20 °C and 65 °C) was investigated and showed that the anodic and the cathodic peaks were increasing,
and more markedly for the 12 M H3PO4. The ratio Q
cathodic/Q
anodic (Q=electrical charge flowing through the electrode) was equal or close to the unity at 20 °C and decreased as the temperature
was increased. The influence of Cl−, Br− and I− ions was also evaluated. The addition of Cl− and Br− predominantly led to Pb5(PO4)3Cl and Pb5(PO4)3Br, respectively, while I− led to a mixture of PbI2 and PbHPO4.
Received: 18 July 1999 / Accepted: 2 November 1999 相似文献
16.
PEO-LiClO4-ZSM5复合聚合物电解质 I. 电化学研究 总被引:3,自引:1,他引:3
首次以“择形”分子筛ZSM5为填料, 通过溶液浇铸法制得PEO-LiClO4-ZSM5全固态复合聚合物电解质(CPE)膜. 交流阻抗实验表明ZSM5的引入可以显著地提高CPE的离子电导率. 利用交流阻抗-稳态电流相结合的方法对CPE的锂离子迁移数进行了测定, 结果表明掺入ZSM5后锂离子迁移数明显升高. ZSM5的含量为10%时, CPE同时具有最高离子电导率1.4×10-5 S•cm-1(25 ℃)和最大锂离子迁移数0.353. PEO-LiClO4-ZSM5/Li电极界面稳定性实验表明PEO-LiClO4-ZSM5复合聚合物电解质在全固态锂离子电池领域具有良好的应用前景. 相似文献
17.
The electrochemical properties of La0.8Sr0.2FeO3???δ (LSF)–La0.45Ce0.55O2???δ (LDC) composite cathodes coated on LSGM electrolyte were studied by electrochemical impedance spectroscopy and cathodic polarization technique. Results showed that the composite cathodes possessed superior electrochemical performance compared to that of pure LSF cathode. The cathodic overpotential of Cathode C was only 100 mV at 0.3 A cm?2, and the charge transfer resistance and the gas phase diffusion resistance were decreased to 0.105 Ω cm2 and 0.257 Ω cm2, respectively at 800 °C. The improvement of the electrochemical performance is contributed to the increase of the triple-phase boundary, enlargement of the effective area for electrode reaction, and increase of the porosity of the cathode by adding LDC to the cathode material. 相似文献
18.
This paper describes the use of an aluminum electrode plated by metallic palladium and modified by Prussian blue (PB/Pd-Al)
in the electrocatalytic reduction of hydrogen peroxide (H2O2). The effect of pH on the electroreduction of H2O2 on the modified electrode is investigated and a simple irreversible reduction pathway is suggested. The electroreduction
kinetics including transfer coefficient α, potential-dependent charge transfer rate constants k
f, and diffusion coefficient D are estimated by means of forced hydrodynamic voltammetry using a rotating disk PB/Pd-Al electrode. The mean values obtained
for kinetics are 0.38, 10−2 cm−1, and 7.6 × 10−6 cm2 s−1, respectively. The long-term stability of the modifying layers on the Al substrate was studied. 相似文献
19.
This paper reports the results of mathematical simulation of electrolysis in a closed electrolytic microcell in a Cu/CuSO4(H2SO4)/Cu system, in which a two-stage electrode reaction, forming a relatively stable intermediate, and chemical reactions between the electrolyte components take place. The dependence of the current that flows through the cell on the electrolysis time and voltage on the cell electrodes was studied by numerical methods. The steady-state profiles of the concentrations of copper-containing species were calculated. The diffusion mass transfer rate in the cell was evaluated. The results were compared with the calculated data for the cell with a recessed electrode configuration with the indicator electrode lying at the bottom of a hole in the insulator. The mass transfer rate in the closed microcell was higher than on the recessed electrode. 相似文献
20.
Y. J. Leng S. H. Chan K. A. Khor S. P. Jiang 《Journal of Solid State Electrochemistry》2006,10(6):339-347
Development of high performance cathodes with low polarization resistance is critical to the success of solid oxide fuel cell
(SOFC) development and commercialization. In this paper, (La0.8Sr0.2)0.9MnO3 (LSM)–Gd0.2Ce0.8O1.9(GDC) composite powder (LSM ~70 wt%, GDC ~30 wt%) was prepared through modification of LSM powder by Gd0.2Ce0.8(NO3)
x
solution impregnation, followed by calcination. The electrode polarization resistance of the LSM–GDC cathode prepared from
the composite powder was ~0.60 Ω cm2 at 750 °C, which is ~13 times lower than that of pure LSM cathode (~8.19 Ω cm2 at 750 °C) on YSZ electrolyte substrates. The electrode polarization resistance of the LSM–GDC composite cathode at 700 °C
under 500 mA/cm2 was ~0.42 Ω cm2, which is close to that of pure LSM cathode at 850 °C. Gd0.2Ce0.8(NO3)
x
solution impregnation modification not only inhibits the growth of LSM grains during sintering but also increases the triple-phase-boundary
(TPB) area through introducing ionic conducting phase (Gd,Ce)O2-δ, leading to the significant reduction of electrode polarization resistance of LSM cathode. 相似文献