Showing papers on "Antimony published in 2015"

Bulk antimony sulfide with excellent cycle stability as next-generation anode for lithium-ion batteries

Abstract: Nanomaterials as anode for lithium-ion batteries (LIB) have gained widespread interest in the research community. However, scaling up and processibility are bottlenecks to further commercialization of these materials. Here, we report that bulk antimony sulfide with a size of 10–20 μm exhibits a high capacity and stable cycling of 800 mAh g−1. Mechanical and chemical stabilities of the electrodes are ensured by an optimal electrode-electrolyte system design, with a polyimide-based binder together with fluoroethylene carbonate in the electrolyte. The polyimide binder accommodates the volume expansion during alloying process and fluoroethylene carbonate suppresses the increase in charge transfer resistance of the electrodes. We observed that particle size is not a major factor affecting the charge-discharge capacities, rate capability and stability of the material. Despite the large particle size, bulk antimony sulfide shows excellent rate performance with a capacity of 580 mAh g−1 at a rate of 2000 mA g−1.

A Chemically Coupled Antimony/Multilayer Graphene Hybrid as a High-Performance Anode for Sodium-Ion Batteries

Abstract: Sodium-ion batteries have recently attracted considerable attention as a promising alternative to lithium-ion batteries owing to the natural abundance and low cost of sodium compared with lithium. Among all proposed anode materials for sodium-ion batteries, antimony is a desirable candidate due to its high theoretical capacity (660 mA h g–1). Herein, an antimony/multilayer graphene hybrid, in which antimony is homogeneously anchored on multilayer graphene, is produced by a confined vapor deposition method. The chemical bonding can realize robust and intimate contact between antimony and multilayer graphene, and the uniform distribution of antimony and the highly conductive and flexible multilayer graphene can not only improve sodium ion diffusion and electronic transport but also stabilize the solid electrolyte interphase upon the large volume changes of antimony during cycling. Consequently, the antimony/multilayer graphene hybrid shows a high reversible sodium storage capacity (452 mA h g–1 at a current...

Atomic layer deposition of antimony oxide films

Abstract: Antimony oxide thin films are deposited by atomic layer deposition using an antimony reactant and an oxygen source. Antimony reactants may include antimony halides, such as SbCl3, antimony alkylamines, and antimony alkoxides, such as Sb(OEt)3. The oxygen source may be, for example, ozone. In some embodiments the antimony oxide thin films are deposited in a batch reactor. The antimony oxide thin films may serve, for example, as etch stop layers or sacrificial layers.

High Thermoelectric Figure of Merit Values of Germanium Antimony Tellurides with Kinetically Stable Cobalt Germanide Precipitates.

Abstract: Heterostructures that consist of a germanium antimony telluride matrix and cobalt germanide precipitates can be obtained by straightforward solid-state synthesis including simple annealing and quenching procedures. The microscale precipitates are homogeneously distributed in a matrix with pronounced “herringbone-like” nanostructure associated with very low thermal conductivities. In comparison to the corresponding pure tellurides, the figure of merit (ZT) values of heterostructured materials are remarkably higher. This is mostly due to an increase of the Seebeck coefficient with only little impact on the electrical conductivity. In addition, the phononic part of the thermal conductivity is significantly reduced in some of the materials. As a result, ZT values of ca. 1.9 at 450 °C are achieved. Temperature-dependent changes of the thermoelectric properties are well-understood and correlate with complex phase transitions of the telluride matrix. However, the high ZT values are retained in multiple measureme...

Squeezing Fluoride out of Water with a Neutral Bidentate Antimony(V) Lewis Acid

Abstract: Because of hydration, fluoride ions in water typically elude complexation by neutral Lewis acids. Here, we show how this limitation can be overcome with a bidentate Lewis acid containing two antimony(V) centers. This derivative (2) is obtained by the simple reaction of 4,5-bis(diphenylstibino)-9,9-dimethylxanthene (1) with two equivalents of 3,4,5,6-tetrachlorobenzoquinone (o-chloranil). It features two square-pyramidal stiborane units oriented in a face-to-face fashion. Titration experiments show that this new bidentate Lewis acid binds fluoride in aqueous solutions containing 95 % water with a binding constant (K) of 700±30 M−1. The structure of the fluoride adduct confirms fluoride anion chelation between the two antimony centers.

Antimony-doped graphene nanoplatelets

Abstract: Heteroatom doping into the graphitic frameworks have been intensively studied for the development of metal-free electrocatalysts. However, the choice of heteroatoms is limited to non-metallic elements and heteroatom-doped graphitic materials do not satisfy commercial demands in terms of cost and stability. Here we realize doping semimetal antimony (Sb) at the edges of graphene nanoplatelets (GnPs) via a simple mechanochemical reaction between pristine graphite and solid Sb. The covalent bonding of the metalloid Sb with the graphitic carbon is visualized using atomic-resolution transmission electron microscopy. The Sb-doped GnPs display zero loss of electrocatalytic activity for oxygen reduction reaction even after 100,000 cycles. Density functional theory calculations indicate that the multiple oxidation states (Sb(3+) and Sb(5+)) of Sb are responsible for the unusual electrochemical stability. Sb-doped GnPs may provide new insights and practical methods for designing stable carbon-based electrocatalysts.

Role of antimony in the phase structure and electrical properties of potassium–sodium niobate lead-free ceramics

Abstract: In the past ten years, antimony has been reported to strongly affect the developments in the piezoelectric properties of (K,Na)NbO3 (KNN) lead-free ceramics, that is, its enhanced piezoelectric activity is closely related to the doped antimony as well its content. In this work, we clarified the role of Sb5+ in the construction of a phase structure and the enhancement of electrical properties of a pure KNN ceramic. Research has shown that doping with Sb5+ can simultaneously move their orthorhombic–tetragonal phase transition temperature (TO–T) and rhombohedral–orthorhombic phase transition temperature (TR–O) forward to room temperature, benefiting the formation of three types of phase boundaries. The coexistence of rhombohedral and orthorhombic phases was established in the Sb5+ composition range of 0.07–0.09 by this regulation. In addition, their grain sizes were determined by the Sb5+ content, that is, the optimum Sb5+ content (x ≤ 0.05) induces grain growth, and their grain sizes become considerably smaller when the compositions deviate from x > 0.05. More importantly, their electrical properties could be also tuned by changing the Sb5+ content. Their dielectric, ferroelectric, and piezoelectric properties are strongly dependent on the antimony content, whereas the strain behavior is mainly ascribed to the multi-phase transition region as well as the structural change of phase transitions. As a result, this work would help to further understand the underlying physical origin for enhanced electrical properties in alkali niobate ceramics.

Structural, optical and charge generation properties of chalcostibite and tetrahedrite copper antimony sulfide thin films prepared from metal xanthates.

Abstract: Herein, we report on a solution based approach for the preparation of thin films of copper antimony sulfide, an emerging absorber material for third generation solar cells. In this work, copper and antimony xanthates are used as precursor materials for the formation of two different copper antimony sulfide phases: chalcostibite (CuSbS2) and tetrahedrite (Cu12Sb4S13). Both phases were thoroughly investigated regarding their structural and optical properties. Moreover, thin films of chalcostibite and tetrahedrite were prepared on mesoporous TiO2 layers and photoinduced charge transfer in these metal sulfide/TiO2 heterojunctions was studied via transient absorption spectroscopy. Photoinduced charge transfer was detected in both the chalcostibite as well as the tetrahedrite sample, which is an essential property in view of applying these materials as light-harvesting agents in semiconductor sensitized solar cells.

Inexpensive Antimony Nanocrystals and Their Composites with Red Phosphorus as High-Performance Anode Materials for Na-ion Batteries

Abstract: Sodium-ion batteries increasingly become of immense research interest as a potential inexpensive alternative to Lithium-ion batteries. Development of high-energy-density negative electrodes (anodes) remains to be a great challenge, especially because of significant differences between lithium and sodium chemistries. Two Na-ion anode materials – antimony (Sb) and phosphorus (P) – have been recently shown to offer excellent cycling stability (Sb) and highest known Na-ion charge storage capacity (P). In this work we report on the synergistic Na-ion storage in a P/Sb/Cu-nanocomposite, produced by mixing inexpensive colloidal Sb nanocrystals with red P and with copper (Cu) nanowires. In comparison to electrodes composed of only phosphorus, such P/Sb/Cu-composite shows much greater cycling stability providing a capacity of above 1100 mAh g−1 after 50 charge/discharge cycles at a current density of 125 mA g−1. Furthermore, P/Sb/Cu-composite also exhibits excellent rate-capability, with capacity of more than 900 mAh g−1 at a high charge/discharge current density of 2000 mA g−1.

Concentration and speciation of antimony and arsenic in soil profiles around the world’s largest antimony metallurgical area in China

Abstract: Mining and smelting activities contribute large amounts of heavy metal pollution to the environment In this study, four 75- or 80-cm-deep soil profiles in the vicinity of the Xikuangshan Sb smelter were sampled and studied by combination of bulk chemical analysis, sequential extraction procedure, and speciation analysis of Sb and As, which are in order to assess the vertical mobility of metal/metalloid contaminants (Sb, As, Cd, and Hg) The heavy contamination in the soil profiles is mostly located in the uppermost soil layers enriched in organic matter (<40 cm) and exhibited downward migration in the soil profiles Sb and As, being substantially bound in the exchangeable fractions by sequential extraction studies, showed significant mobility in the profiles Sb(III), Sb(V), As(III), and As(V) were found in all of the soil samples, and certain methylated states of Sb (TMSb) and As (MMA, DMA) were also present in the lower layer soil samples

Surfactant effect of antimony addition to the morphology of self-catalyzed InAs1-x Sb (x) nanowires

Abstract: The effect of Sb addition on the morphology of self-catalyzed InAsSb nanowires (NWs) has been systematically investigated. InAs NWs were grown by molecular beam epitaxy with and without antimony (Sb) flux. It is demonstrated that trace amounts of Sb flux are capable of tuning the geometry of NWs, i.e., enhancing lateral growth and suppressing axial growth. We attribute this behavior to the surfactant effect of Sb which results in modifications to the kinetic and thermodynamic processes. A thermodynamic mechanism that accounts for Sb segregation in InAsSb NWs is also elucidated. This study opens a new route towards precisely controlled NW geometries by means of Sb addition.

Progress in development of copper antimony sulfide thin films as an alternative material for solar energy harvesting

Abstract: The increasing energy demand and the limitations of the existing technologies due to the scarcity, cost and toxicity of the materials urge the researchers to hunt for efficient thin film solar cells based on earth-abundant, inexpensive and less toxic materials. For a decade, binary and ternary antimony based sulfides have gained attention due to their possible applications in solar cells. This interest is the basis of this review. In this review article, we describe basic properties of copper antimony sulfide (CuSbS2) thin films to investigate their photovoltaic applications. A detailed description of the preparation methods, studies on morphologies and optoelectronic properties based on published work, including our experience are presented. A systematic review is done to demonstrate emerging interest in the photovoltaic performance of this compound. This review gives an in depth discussion on the structure, morphology, optical and electrical properties of copper antimony sulfide thin films.

Metallic modified (bismuth, antimony, tin and combinations thereof) film carbon electrodes

Abstract: In this paper in situ bismuth, antimony, tin modified electrodes and combinations thereof are explored towards the model target analytes cadmium(II) and lead(II), chosen since they are the most widely studied, to explore the role of the underlying electrode substrate with respect to boron-doped diamond, glassy carbon, and screen-printed graphite electrodes. It is found that differing electrochemical responses are observed, dependent upon the underlying electrode substrate. The electrochemical response using the available range of metallic modifications is only ever observed when the underlying electrode substrate exhibits relatively slow electron transfer properties; in the case of fast electron transfer properties, no significant advantages are evident. Furthermore these bismuth modified systems which commonly employ a pH 4 acetate buffer, reported to ensure the bismuth(III) stability upon the electrode surface can create create a problem when sensing at low concentrations of heavy metals due to its high background current. It is demonstrated that a simple change of pH can allow the detection of the target analytes (cadmium(II) and lead(II)) at levels below that set by the World Health Organisation (WHO) using bare graphite screen-printed electrodes.

Assessment of Hybrid Organic–Inorganic Antimony Sulfides for Earth-Abundant Photovoltaic Applications

Abstract: Hybrid organic–inorganic solar absorbers are currently the subject of intense interest; however, the highest-performing materials contain Pb. Here we assess the potential of three Sb-based semiconductors: (i) Sb2S3, (ii) Cs2Sb8S13, and (iii) (CH3NH3)2Sb8S13. While the crystal structure of Sb2S3 is composed of 1D chains, 2D layers are formed in the ternary cesium and hybrid methylammonium antimony sulfide compounds. In each case, a stereochemically active Sb 5s2 lone pair is found, resulting in a distorted coordination environment for the Sb cations. The bandgap of the binary sulfide is found to increase, while the ionization potential also changes, upon transition to the more complex compounds. Based on the predicted electronic structure, device configurations are suggested to be suitable for photovoltaic applications.

Different mechanisms and electrocatalytic activities of Ce ion or CeO2 modified Ti/Sb–SnO2 electrodes fabricated by one-step pulse electro-codeposition

Abstract: Sb-doped SnO2 electrode was fabricated by the one-step pulse electro-codeposition method, and was modified through either cerium dioxide nanoparticle (nano-CeO2) or cerium ion doping The results showed that the effects of nano-CeO2 doping and cerium ion doping are quite different Nano-CeO2 doping shrinks the unit cell volume, improves the degree of crystallinity and refines crystalline grains, while cerium ion doping expands the volume and deteriorates the crystallinity Nano-CeO2 doping mitigates the surface antimony enrichment and promotes the complete oxidation of antimony so that the majority of antimony oxidation states exist as the Sb5+ state, but cerium ion doping aggravates the enrichment and increases the Sb3+ content Electrochemical phenol degradation showed that the Ti/Sb–SnO2–CeO2 electrode has a higher degradation efficiency and its kinetic rate constant is 146 times as much as that of Ti/Ce–Sb–SnO2 Besides, due to the compact active layer of Ti/Sb–SnO2–CeO2 protecting the titanium substrate from passivation, the accelerated service lifetime of Ti/Sb–SnO2–CeO2 is prolonged, which is 128 times as long as that of Ti/Ce–Sb–SnO2

Effect of organic matter on arsenic(V) and antimony(V) adsorption in soils

Abstract: Summary The interaction of toxic oxyanions with organic matter can affect their stability and binding mechanisms in soils. The adsorption/desorption properties of arsenic (AsV)/antimony (SbV) oxyanions were tested with two types of soil with a variable content of natural organic matter (NOM). Sample JEZ (I) represented a locality near a brown-coal power plant, and therefore formerly exposed to large amounts of atmospheric pollution, while sample LIZ (II) originated in an uncontaminated region without anthropogenic impact. Soil samples were investigated from the organic O and mineral B horizons. Different As/Sb fixations were indicated by their different adsorption affinity to O and B horizons. Arsenic as AsV was strongly adsorbed in B horizons, while antimony as SbV was predominantly bound in O horizons. The sorption followed the Langmuir model with maximum adsorption capacities of 1.4 × 10−2 mmol g−1 for As and 1.0 × 10−2 mmol g−1 for Sb adsorptions. The release of As and Sb to distilled water and 0.1 m KCl illustrated the significantly larger stability of As and Sb oxyanions in ionic solutions, where available ions prevented the aggregation of organic matter, thus maintaining the balanced distribution of surface charge. Distilled water with a pH of about 6 supported a negative surface charge density and enhanced the release of As/Sb oxyanions.