Goethite nanorods as anode electrode materials for rechargeable Li-ion batteries

Although various transition metal oxides have been reported to act as low potential Li insertion hosts, the oxyhydroxides have remained unexplored to date. We show here that the hydroxide ions present in transition metal oxyhydroxides do not interfere with the lithium uptake and extraction, permitting very good reversibility of the reduction/oxidation reactions. Goethite (α-FeOOH) nanocrystals can uptake and extract large amount of Li via the conversion reaction mechanism, providing a reversible capacity of 500 mA h g⁻¹ at an average potential of 0.85 V vs. Li/Li⁺. The mechanism was examined using a combination of X-ray diffraction, electron microscopy, and the corresponding selected area electron diffractions (SAEDs). The α-FeOOH is reduced into nanoparticles of metallic Fe⁰ embedded in an amorphous matrix of Li₂O and LiOH in the first discharge; the subsequent cyclings are redox reactions between metallic Fe⁰ and Fe₂O₃ clusters.     

Fabrication of highly porous and micropatterned SnO2 films by oxygen bubbles generated on the anode electrode

The fabrication process of highly porous SnO(2) thick film by reaction between tin ions and oxygen gas generated by an anodic applied potential on substrates in SnCl(2) aqueous solution is reported; moreover, we succeeded in forming porous SnO(2) micropatterns through site-selective deposition on a Pt-patterned F-doped SnO(2)(FTO) coated substrate .     

Intrinsic characteristics of cathode and anode materials for lithium-ion batteries

Fundamental aspects of solving the problem of how the working capacity of lithium-ion batteries in prolonged cycling can be raised and the basic tendencies in the relationship between the intrinsic parameters of active materials of various brands and the electrochemical behavior of anodes and cathodes fabricated from these materials are considered.     

Determination of dehydrogenase substrates by Clark-type oxygen electrodes and photosensitized coenzyme oxidation

The photosensitized oxidation of NADPH by oxygen can be used for the determination of the reduced coenzymes by means of a Clark oxygen electrode. This method is suitable for coupling to enzyme-catalysed dehydrogenation reactions and thus for the determination of glucose-6-phosphate with glucose-6-phosphate dehydrogenase and of glucose with the combined ATP/hexokinase/glucose-6-phosphate dehydrogenase system, even with the use of immobilized mediators.     

Effect of the electrode material on the oxygen reduction at the nonstoichiometric lanthanum fluoride/electrode interface

The voltammetry method with a linear potential scan is used for investigating the effect the electrode material (Ni, Co, electrodes on the basis of cobalt oxides modified with carbon) exerts on the reduction of gaseous oxygen at interfaces solid fluoride-conducting electrode LaF₃:Eu²⁺/electrode, O₂, and conjugated processes. Properties of the modified electrodes are characterized by the impedance spectroscopy, scanning electron microscopy, and x-ray photoelectron spectroscopy methods. The oxygen reaction is irreversible at the LaF₃:Eu²⁺|Ni (or Co) interfaces. At the interface of LaF₃:Eu²⁺ with modified electrodes Co (C n at %), where n = 5 and 9, mobile forms of oxygen are reversible and the reduction of gaseous and chemisorbed oxygen is controlled by diffusion with different effective kinetic parameters.     

Effect of oxygen vacancies in anodic titanium oxide films on the kinetics of the oxygen electrode reaction

The effect of oxygen vacancies in the anodic oxide film on passive titanium on the kinetics of the oxygen electrode reaction has been studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Oxide films of different donor density were prepared galvanostatically at various current densities until a potential of 20.0 V_SHE was achieved. The semiconductive properties of the oxide films were characterized using EIS and Mott-Schottky analysis, and the thickness was measured using ellipsometry. The film thickness was found to be almost constant at ∼44.7 ± 2.0 nm, but Mott-Schottky analysis of the measured high frequency interracial capacitance showed that the donor (oxygen vacancy) density in the n-type passive film decreased sharply with increasing oxide film formation rate (current density). Passive titanium surfaces covering a wide range of donor density were used as substrates for ascertaining relationships between the rates of oxygen reduction/evolution and the donor density. These studies show that the rates of both reactions are higher for passive films having higher donor densities. Possible explanations include enhancement of the conductivity of the film due to the vacancies facilitating charge transfer and the surface oxygen vacancies acting as catalytic sites for the reactions. The possible involvement of surface oxygen vacancies in the oxygen electrode reaction was explored by determining the kinetic order of the OER with respect to the donor concentration. The kinetic orders were found to be greater than zero, indicating that oxygen vacancies are involved as electrocatalytic reaction centers in both the oxygen evolution and reduction reactions. This paper was submitted in honor of the many contributions to electrochemistry that have been made by Professor Boris Grafov. The article is published in the original.     

不同pH下多晶Au电极上的氧还原反应

利用旋转圆盘电极体系系统研究了不同pH下氧气在多晶Au电极上的还原反应,并计算了不同pH条件及不同超电势范围内的Tafel斜率.研究发现,同在酸性（但是pH不同）或同在碱性（但是pH不同）的介质中氧还原起始电位以及纯粹动力学控制区（电流较小的区域）的氧还原电流几乎不随溶液的pH值而变化.酸性条件下以及碱性条件的高超电势范围内,Tafel斜率接近120mV/dec;而碱性条件的低超电势范围内,Tafel斜率接近60mV/dec.金电极上ORR的活化超电势随着pH值的增加而降低约79mV/pH.初步讨论了pH对氧还原机理和动力学的影响及其内在原因.     

Effect of graphene nanosheet addition on the electrochemical performance of anode materials for lithium-ion batteries

The structure and electronic properties of graphene nanosheet (GNS) render it a promising conducting agent in a lithium-ion battery. A graphite electrode loaded with GNS exhibits superior electrochemical properties including higher rate performance, increased specific capacity and better cycle performance compared with that obtained by adding the traditional conducting agent–acetylene black. The high-quality sp² carbon lattice, quasi-two-dimensional crystal structure and high aspect ratio of GNS provide the basis for a continuous conducting network to counter the decrease in electrode conductivity with increasing number of cycles, and guarantee efficient and fast electronic transport throughout the anode. Effects of GNS loading content on the electrochemical properties of graphite electrode are investigated and results indicate that the amount of conductive additives needed is decreased by using GNS. The kinetics and mechanism of lithium-storage for a GNS-loaded electrode are explored using a series of electrochemical testing techniques.     

Electrochemical trifluoromethylation of ethylene on various anode materials

Glassy carbon, smooth platinum, and platinum-plated glassy carbon were tested as anode materials in electrochemical trifluoromethylation of ethylene. The reaction products were identified and specific features of the process were examined.     

Effect of oxidative stabilization on the electrochemical performance of carbon mesophases as electrode materials for lithium batteries

The effect of oxidative stabilization as a mean to modify the carbon texture was essayed in a group of mesophases previous to carbonization at 900 °C with the aim of evaluating the influence on electrochemical performance when used as electrode materials in lithium test cells. X-ray diffraction, optical microscopy and chemical analysis, Fourier-transform infrared spectroscopy have been used to describe the compositional and textural properties of the as-produced parent mesophases, the samples were further treated under air current to stabilize their microstructures and the corresponding carbonized samples at 900 °C. The electrochemical performance was determined by the galvanostatic method and further correlated to the physical–chemical properties and interface resistance of the materials. In all cases, the stabilization process has demonstrated a beneficial effect on the capacity retention in the measured range.     

Dealloying technique in the synthesis of lithium-ion battery anode materials

In the last decade, dealloying has become a popular and effective strategy to fabricate nanoporous metals used in electrochemical applications such as electrocatalysis and energy storage. This review article summarizes the recent literature on dealloyed non-noble metals and oxides evaluated as lithium-ion battery anode materials. The importance of dealloying parameters to achieve desired pore and ligament sizes is emphasized. A future research roadmap is also provided.     

Recent progress on Ge oxide anode materials for lithium-ion batteries

正1 Introduction As environmental pollution continues to worsen,governments are increasing their efforts to develop green transport vehicles,such as electric vehicles and hybrid cars.Efficient energy storage and conversion systems are urgently needed     

A review on anode materials for lithium/sodium-ion batteries

Since lithium-ion batteries(LIBs) have been substantially researched in recent years, they now possess exceptional energy and power densities, making them the most suited energy storage technology for use in developed and developing industries like stationary storage and electric cars, etc. Concerns about the cost and availability of lithium have prompted research into alternatives, such as sodium-ion batteries(SIBs), which use sodium instead of lithium as the charge carrier. This is especially ...     

Co-MOFs材料在锂离子电池负极材料中的应用研究进展

该文阐述了近年来钴金属有机骨架(Co-MOFs)材料在锂离子电池负极材料中的应用研究进展,分别对Co-MOFs材料及Co-MOFs衍生的氧化钴、氧化钴/碳复合材料、硫化钴/碳复合材料等用作锂离子电池负极材料进行了分类总结,旨在为广大研究者提供相关方面的信息.     

Characterization methods of organic electrode materials

The development of novel organic electrode materials is of great significance for improving the reversible capacity and cycle stability of rechargeable batterie...     

Effect of phase stability degradation of bismuth on sensor characteristics of nano-bismuth fixed electrode

Effect of phase stability degradation of bismuth on sensor characteristics of nano-bismuth fixed electrode has been investigated using square-wave anodic stripping voltammetry technique, scanning electron microscopy (SEM) and X-ray diffraction (XRD) spectroscopy. From the analyses of square-wave anodic stripping voltammograms (SWASV) repetitively measured on the nano-bismuth fixed electrode, it was found that the oxidation peak currents dropped by 81%, 68% and 59% for zinc, cadmium and lead, respectively, after the 100th measurement (about 400 min of operation time). The sphere bismuth nanoparticles gradually changed to the agglomerates with petal shape as the operation time increased. From the analyses of SEM images and XRD patterns, it is confirmed that the oxidation of Bi into BiOCl/Bi₂O₂CO₃ and the agglomeration of bismuth nanoparticles caused by the phase change decrease a reproducibility of the stripping voltammetric response. Moreover, most of the bismuth becomes BiOCl at pH 3.0 and bismuth hydroxide, Bi(OH)₃ at pH 7.0, which results in a significant decrease in sensitivity of the nano-bismuth fixed electrode.     

化学修饰电极的研究 V:铁卟啉修饰电极对氧的催化还原

By surface organio synthesis a Fe (III) tetra-o-aminophenyl porphyrin modified electrode was successfully prepared on glassy carbon electrode surface through amidization. The preparation considitions were invesigated in detail. Using cyclie voltametry and cyclie semidifferential polarography in an acidic aqueous solution the behavior of the catalytic reduction of oxygen on iron porphyrin modified electrode was studied. Based on experimental results it was shown that the irreversible process of 2- electronreduction to hydrogen peroxide belongs to EC parallel catalytic process.