Graphene oxide supported tin dioxide: synthetic approaches and electrochemical characterization as anodes for lithium- and sodium-ion batteries

The review addresses synthetic approaches to composite materials based on graphene oxide and nano tin dioxide and their electrochemical properties as anodes for lithium- and sodiumion batteries. The introduction of a carbon matrix into the composite material improves the electrochemical characteristics of the anodes. In most methods, the synthesis of graphene oxide–tin dioxide composites is based on the use of tin(II,IV) chlorides as the starting compounds, and the most efficient electrode materials were obtained by the hydrothermal or solvothermal routes. Thermal processing is much more economic than the gas phase deposition protocols but requires heating of a large volume of dilute tin oxide dispersions in an autoclave. Mechanochemistry (ball milling) is also economically unfavorable for the synthesis of composite materials. In addition, large volumes of acidic wastes that should be neutralized and safely discarded are formed when tin chlorides are used. An alternative environmentally friendly technique based on the use of aqueous peroxide solutions can be applied for the production of efficient anode materials based on graphene oxide and tin dioxide. This process does not involve acidic wastes, uses hydrogen peroxide and ethanol as reagents, and accomplishes film deposition (coating) at room temperature. Final thermal treatment is required only for the active material, which minimizes energy expenses and equipment costs.     

用于锂离子电池负极材料的锡/碳复合材料研究

采用分散聚合的方法在氧化锡的表面包覆聚对位二乙烯基苯,再热解制备了锡基颗粒在碳基体中均匀分散的锡/碳复合材料.该复合材料具有良好的循环性能.在该复合材料中无定形碳起到了至关重要的作用,它一方面保证了复合材料的导电性能,另一方面有效地抑制了锡基颗粒的团聚与粉化.只有当小尺寸的锡基颗粒均匀地分散在碳基体中时,锡/碳复合材料才具有稳定的电化学性能.     

Cyclic stability of the anode material based on tin(IV) oxide for thin-film current sources

The cyclic stability of thin films (~40 nm) of an anode material based on tin dioxide at charging voltages of 2.5, 1.5, and 0.8 V was studied. The electrodes were prepared on a Picosun R-150 installation using tetraethyltin and remote inductively coupled oxygen plasma.     

锂离子电池碳包覆锡负极性能研究

应用水热法分解葡萄糖制作锂离子电池碳包覆锡负极. 充放电测试表明,添加5%（by mass）乙炔黑导电剂的该电极初始放电比容量达967 mAh.g^-1,经50周循环其放电比容量仍保持362 mAh.g^-1,远高于锡电极的比容量（50周循环166 mAh.g^-1）. 碳包覆可防止锡粉团聚,降低锡的不可逆容量损失. 而添加乙炔黑可降低碳包覆电极与电解液间的交流阻抗,改善电极内部锂离子及电子的传导通道,从而也提高了该电极的初始放电比容量.     

Electrochemical Performance Studies of Tin Oxide Prepared by Sol-Gel

IntroductionSince the introduction of commercial lithium-ion batteries for the portable devices in the 1 990′s,the search for new anode materials with improvedenergy density and cycle- ability has never beenstopped[1— 5] .Graphite used as the early commercialanode material for lithium- ion batteries over otherkinds of materials in terms of its flat intercalationpotential and high cycle- ability[6,7] can′t keep pacewith the demand today because of its low capacity.In resentyears,the greateff…     

Determination of tin and triorganotin compounds in sea-water by graphite-furnace atomic-absorption spectrophotometry

An analytical method based on graphite-furnace atomic-absorption spectrophotometry employing a suitable signal-enhancing medium for determination of inorganic tin and two of its trisubstituted organic derivatives in sea-water has been established. This method allows determination of triphenyltin and tributyltin compounds down to 2 x 10(-12) and 2.8 x 10(-12)M respectively by means of enrichment by collection on graphitized carbon black (enrichment factor up to 8 x 10(4)) and a separation on a small silica-gel column. Inorganic tin, which is not adsorbed on the graphitized carbon black, is isolated from the matrix by liquid-liquid extraction of its pyrrolidinedithiocarbamate complex into dichloromethane. The method gives good recovery (95%) and precision ( less, similar5%) at the ng/l. level.     

Determination of oxalate in black liquor by headspace gas chromatography

This study demonstrated a headspace gas chromatographic method (HS-GC) for the determination of oxalate content in black liquor (alkaline aqueous solution of inorganic chemicals and dissolved wood species from the alkaline pulping of wood). The method described in this paper is based on the reaction between oxalic and manganese dioxide in an acidic medium, in which oxalic acid is converted to carbon dioxide that is measured with a GC using a thermal conductivity detector. The challenge in developing this method was ensuring complete conversion of oxalic acid while minimizing the contribution of side reactions between carbohydrates, lignin and manganese dioxide to the carbon dioxide measured. It was found that a complete conversion of oxalate to carbon dioxide can be achieved within 3 min at a temperature of 70 degrees C; a MnO(2):C(oxalate) (concentration of H(2)C(2)O(4)+HC(2)O(4)(-)+C(2)O(4)(2-)) mole ratio of 60 and H(2)SO(4) concentration of 0.005-0.01 mol/L in the headspace vial. The method can detect concentrations as low as 0.39 microg of oxalate. The standard deviation was found to be 7% while recovery experiments with black liquor showed recoveries of 93-108% which were deemed acceptable for analysis of oxalate in an industrial sample such as black liquor.     

Highly improved carbon dioxide sensitivity and selectivity of black phosphorene sensor by vacancy doping: A quantum chemical perspective

The adsorption and sensing properties of a carbon dioxide (CO₂) molecule on the pristine (BP) and vacancy-doped (DP) black phosphorusmono layers have been investigated using the periodic density functional theory at Heyd-Scuseria-Ernzerhof (HSE06)/triple-zeta valence polarization (TZVP). For both sensors, the most stable structures among the recognized possibilities preferred a linear configuration for carbon dioxide, with a shorter equilibrium distance (2.13 Å) on the defect-containing surface. Although carbon dioxide was weakly physiosorbed on both phosphorene sensors (up to −2.52 kcal/mol), the defect-engineered material presented highly improved sensitivity (by a factor of 6.6) to CO₂ compared to the pristine layer. The former was also a (2.6 times) better work function sensor of carbon dioxide. At the same time, recovery was extremely fast (lasting for 70 ps at most) at room temperature. The selectivity coefficient of carbon dioxide was also strikingly high (64.0). The improved nanosensor would be a step forward in the rational design of highly sensitive and reusable detectors of carbon dioxide.     

Study of tin dioxide–sodium stannate composite obtained by decomposition of peroxostannate as a potential anode material for lithium-ion batteries

A tin dioxide–sodium stannate composite has been obtained by the thermal treatment of sodium peroxostannate nanoparticles at 500°C in air. X-ray powder diffraction study has revealed that the composite includes crystalline phases of cassiterite SnO₂, sodium stannate Na₂Sn₂O₅, and sodium hexahydroxostannate Na₂Sn(OH)₆. Scanning electron microscopy has shown that material morphology does not change considerably as compared with the initial tin peroxo compound. Electrochemical characteristics have been compared for the anodes of lithium-ion batteries based on tin dioxide–sodium stannate composite and anodes based on a material manufactured by the thermal treatment of graphene oxide–tin dioxide–sodium stannate composite at 500°C in air.     

Synthesis and Gas-sensing Performance of Nanosized SnO2

Nanosized tin dioxide particles were prepared by sol-gel dialytic processes with tin(Ⅳ) chloride and alcohol as start materials. The nanoparticles of tin dioxide were charactered by thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET. The results show that the average diameter of tin dioxide particles dried at 353 K was about 2nm. Even if the tin dioxide particles were calcined at 873 K, the average diameter of particles was less than 10 nm. The removal of Cl^- was solved by using this kind of method. The mechanism of the formation of tin dioxide nanosized particles was proposed and analyzed in this paper. We also measured the sensitivity of the sensor based on the tin oxide powder calcined at 673K to NH3, alcohol, acetone, hexane and CO. The gas-sensing performance results indicate that this sensor has a higher sensitivity to alcohol and acetone, and selectivity for NH3, hexane and CO at an operating temperature of 343 K.     

Manganese Dioxide Graphite Composite Electrodes Formed via a Low Temperature Method: Detection of Hydrogen Peroxide,Ascorbic Acid and Nitrite

Manganese dioxide modified carbon powder was prepared via a wet impregnation method from the solution of permanganate salt. After heating at 120 °C over night in air, the formation of manganese oxide was confirmed by cathodic stripping voltammetry. The synthesized material was used for fabrication of composite electrodes and their potential application in the field of electroanalysis investigated. The composite electrodes based on the manganese dioxide modified carbon powder proved to be useful as electrodes for detection of hydrogen peroxide, ascorbic acid and nitrite ions.     

Electrodeposited lead dioxide coatings

Lead dioxide coatings on inert substrates such as titanium and carbon now offer new opportunities for a material known for 150 years. It is now recognised that electrodeposition allows the preparation of stable coatings with different phase structures and a wide range of surface morphologies. In addition, substantial modification to the physical properties and catalytic activities of the coatings are possible through doping and the fabrication of nanostructured deposits or composites. In addition to applications as a cheap anode material in electrochemical technology, lead dioxide coatings provide unique possibilities for probing the dependence of catalytic activity on layer composition and structure (critical review, 256 references).     

纳米锡/硬碳复合材料作为嵌锂负极的研究

利用金属铁和钴纳米颗粒的催化活化作用,制备了多孔硬碳球.应用聚焦离子束切割技术,观察到扩孔后的硬碳球中充满彼此连通的发达中孔.在此多孔硬碳球中填入纳米锡(Sn)颗粒,对复合材料的电化学性能进行了测试.     

Graphitized carbon black in polyethylene as an electrochemical sensor

The electrochemical behaviour of a material obtained by moulding graphitized carbon black and polyethylene at 100–150°C is described. The material can be used as a pellet electrode in voltammetric procedures. As a tubular anode held in a teflon body, the material is valuable as a sensor for high-performance liquid chromatography. Its properties are comparable with those of glassy carbon with better signal-to-noise ratios. It is applied for the determination of several phenols, chlorophenols and hydroquinone in the low mg l^?1 range or less.     

Adsorption of several tracer cations and separation of234Th from238U and113mIn from113Sn on tin dioxide

The uptake of 22 cations at tracer concentrations has been studied over hydrous tin dioxide exchanger material. A granular variety of tin dioxide was prepared from the reaction of tin(IV) chloride with NaOH solution, and the formula of the material was ascertained to be SnO₂·1.7 H₂O. Radiochemical separation of carrier-free²³⁴Th from²³⁸U and^113mIn from¹¹³Sn was achieved over a tin dioxide column. The separated products were of high radionuclidic purity. The overall separation procedures are very simple and quick with quantitative yield.     

Characterization and analysis of new catalysts for a direct ethanol fuel cell

A direct ethanol fuel cell offers an attractive, fairly high density, energy source, if an electrochemical system can be developed that efficiently carries out the 12-electron oxidation of ethanol to carbon dioxide and water. To that end, new catalyst systems must be developed along with fuel cell operating conditions that encourage the complete oxidation of ethanol, as opposed to the presently available platinum on carbon systems that tend to produce acetaldehyde (two-electron oxidation) or acetic acid (four-electron oxidation) products. It is found that a composite nanoparticulate catalyst containing platinum and tin oxide or platinum indium tin oxide allows the partial conversion of ethanol to its 12-electron oxidation products. Catalysts of this type can be formed using a modified polyol process. Elevation of the operating temperature of a proton exchange membrane fuel cell using the indicated catalysts to 130 degrees C facilitates the production of carbon dioxide and provides an improved current-voltage response.     

Carbon Dioxide Measurements with and without Barium Peroxide in Electrolytic Studies with and without a Supporting Electrolyte

Abstract

This research deals with the quantitative formation of carbon dioxide in electrolytic oxidation reactions. The electrolytic reactions were run with barium peroxide to generate the superoxide anion at the anode. With the organic compounds used in these electrolytic studies we needed to develop a method where we could determine the amount of carbon dioxide liberated from these compounds with the superoxide anion. This method degasses an acidified solution with dry nitrogen, which carries the carbon dioxide to a standard solution of sodium hydroxide. Titration of the sodium hydroxide solution with standardized hydrochloric acid revealed the amount of carbon dioxide formed in the reaction after precipitation of the carbonate ions with barium chloride. Blank runs with the apparatus using anhydrous sodium carbonate produced 99% plus results of recovered carbon dioxide from the sodium carbonate.     

Leak testing of carbon–tin nanocomposites by thermal analysis methods

Electrode materials consisted of tin nanograins encapsulated in different origin carbon buffer matrix (starch or water soluble polymer) were obtained in a simple and inexpensive process. The tin precursor was synthesized using modified reverse nanoemulsion technique (w/o) and then coated by a source of carbon. The composites precursors were pyrolysed, affording formation of C/Sn anode materials. The resulting samples were investigated by powder X-ray diffraction studies in order to verify the structure and calculate crystallites sizes. The morphology of the nanocomposites was characterized by low-temperature nitrogen adsorption method (N₂-BET). Thermal analysis measurements (EGA-TG/DTG/DTA and DSC) allowed determining optimal conditions of preparation process and estimating carbon content in the obtained anode materials. Thermogravimetric studies also proved to be highly useful in establishing the leak behaviour of C/Sn nanocomposites. The electrochemical performance of the nanopowders was examined by charge–discharge tests in R2032-type coin cell. The thermal analysis results as well as low-temperature nitrogen adsorption data indicated that the origin of carbon precursor has major impact on morphology and leak behaviour of the obtained carbon buffer matrix. The electrochemical tests showed that better tightness of carbon–tin nanocomposites resulted in higher gravimetric capacity and better cell performance.     

球形Sn-SnSb合金纳米粒子制备及其储锂性能

锂离子电池Sn负极材料有较高的比容量,但其容量随周期循环急剧衰减. 若Sn与Sb形成SnSb合金可以改善其循环性能. 本文采用有机液相还原方法制备了球形Sn-SnSb合金纳米粒子,其首周期循环充电容量1235.9 mAh·g^-1,放电容量为785.9 mAh·g^-1,经过50周的循环之后其放电容量保持在409.2 mAh·g^-1,表现出较好的循环性能.     

Solar-powered electrochemical oxidation of organic compounds coupled with the cathodic production of molecular hydrogen

A Bi-doped TiO2 anode, which is prepared from a mixed metal oxide coating deposited on Ti metal, is shown to be efficient for conventional water splitting. In this hybrid photovoltaic-electrochemical system, a photovoltaic (PV) cell is used to convert solar light to electricity, which is then used to oxidize a series of phenolic compounds at the semiconductor anode to carbon dioxide with the simultaneous production of molecular hydrogen from water/proton reduction at the stainless steel cathode. Degradation of phenol in the presence of a background NaCl electrolyte produces chlorinated phenols as reaction intermediates, which are subsequently oxidized completely to carbon dioxide and low-molecular weight carboxylic acids. The anodic current efficiency for the complete oxidation of phenolic compounds ranges from 3% to 17%, while the cathodic current efficiency and the energy efficiency for hydrogen gas generation range from 68% to 95% and 30% to 70%, respectively.