batterydata/paper-abstracts huggingface dataset:
Poly(3,4-ethylenedioxythiophene)/polypyrrole composite electrodes were prepared by electropolymerization of 3,4-ethylenedioxythiophene (EDOT) on the surface of polypyrrole (PPy) modified tantalum electrodes. The electrochemical capacitance properties were investigated with cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) techniques with two- or three-electrode cell configuration. The data showed that the specific capacitance of composite electrodes, due to the synergic effect of poly(3,4-ethylenedioxythiophene) (PEDOT) and PPy, is much higher than the values of either pure PEDOT or pure PPy electrodes. Moreover, the composites prepared on the surface of PPy with horn-like structure allow the specific capacitance up to more than 200Fg−1 and have a good cycleability. This implies that PEDOT/PPy composites are promising to be used as electrode material of supercapacitors.
A major challenge in the development of Li–O2 batteries is the high overpotential required for battery operation, especially during the charging process. Various precious metals and their corresponding oxides have been proposed as electrocatalysts to reduce the charge voltage of Li–O2 batteries. However, the real mechanism by which these solid catalysts decompose Li2O2 during the charge process is still under debate. Here, Ru nanoparticles supported on carbon matrixes with ultrahigh dispersibility were synthesized and evaluated as cathode materials for Li–O2 batteries. The charge voltage of the corresponding Li–O2 battery was reduced to below 4.1 V (V vs. Li/Li+), and a stable cycling performance over more than 100 cycles was achieved. Nevertheless, differential electrochemical mass spectrometry measurements revealed that large amounts of gaseous by-products evolved even during the first charge process, suggesting that severe parasitic reactions accompanied the decomposition of Li2O2. The undesired degradation of the carbon cathode and/or electrolyte was also accelerated in the presence of Ru. Thus, this study has revealed that previous conclusions regarding the role of Ru in catalytically decomposing Li2O2 may be misleading. Furthermore, the necessity of performing quantitative analysis of gas evolution in order to study the real performance of Li–O2 batteries has been demonstrated.
Birnessite type manganese dioxides containing a small amount of vanadium were synthesized by oxidizing manganese nitrate with vanadium xerogel and hydrogen peroxide in a basic solution. When the nominal manganese/vanadium molar ratio was between 0.25 and 1, the resulting samples possessed birnessite type structure with irregular stacking of manganese dioxide layers, otherwise the products became amorphous. The obtained birnessite type manganese dioxides had a characteristic sponge-like and open-network microstructure composed of interconnected bent layer and the particle size was very small, less than 1μm. The discharge capacity at the second cycle became maxima and reached 250mAhg−1 for the sample prepared with the nominal Mn/V ratio of 1 and the cycling property was relatively good. The increase of utilization of active material due to the increase of electrical conductivity as the result of introduction of vanadium and/or the characteristic microstructure would lead the high discharge capacity. The irregular stacking of manganese oxide layers would be responsible for the relatively good cycling behavior.
In this work the electrochemical behavior of different thiols on fluorine doped tin oxide (FTO) electrodes is reported. To this end, the mechanism of electrochemical oxidation of glutathione (GSH), cysteine (Cys), homocysteine (HCys) and acetyl-cysteine (ACys) at different pH was investigated. FTO showed electroactivity for the oxidation of the first three thiols at pH between 2.0 and 4.0, but under these conditions no acetyl-cysteine oxidation was observed on FTO. Voltammetric studies of the electro-oxidation of GSH, Cys and HCys showed peaks at about 0.35, 0.29, and 0.28V at optimum pH 2.4, 2.8 and 3.4, respectively. In addition, this study demonstrated that GSH, Cys and HCys oxidation occurs when the zwitterion is the electro-active species that interact by adsorption on FTO electrodes. The overall reaction involves 4e−/4H+ and 2e−/2H+, respectively, for HCys and for GSH and Cys and high heterogeneous electron transfer rate constants. Besides, the use of FTO for the determination of different thiols was evaluated. Experimental square wave voltammetry shows a linear current vs. concentrations response between 0.1 and 1.0mM was found for HCys and GSH, indicating that these FTO electrodes are promising candidates for the efficient electrochemical determination of these endogenous thiols.
Patterned and thin-film electrode experiments are effective in isolating or separating the complex charge and mass transport processes involved in the oxygen reduction reaction within and on the surface of a mixed-conducting solid oxide fuel cell cathode, making it possible to correlate electrochemical performance with electrode geometry, reaction pathway, and limiting steps. Very little information about either the impact of sheet resistance on global response or on effective design of current collector configuration to avoid sheet resistance has been reported to date, however. In this contribution, an empirical numerical model is presented to simulate sheet resistance under various material and catalytic parameters, current collector configurations, and other experimental factors in thin-film, mixed-conducting working electrodes. This model is used to provide general guidance for effective current collector placement by mapping in parameter space. In general, continuous crisscrossing metal lines, deposited through e.g. photolithography, provide the best intra-film current collection while small, regularly spaced discrete contacts, provided by e.g. a metal mesh, provide less efficient intra-film current collection. Most thin-film aspect ratios and current collector configurations can be accommodated without severe intra-film sheet resistance limitation provided the current collectors are spaced appropriately.
Br-doped Li4Ti5O12 in the form of Li4Ti5O12−x Br x (0≤ x ≤0.3) compounds were successfully synthesized via solid state reaction. The structure and electrochemical properties of the spinel Li4Ti5O12−x Br x (0≤ x ≤0.3) materials were investigated. The Li4Ti5O12−x Br x (x =0.2) presents the best discharge capacity among all the samples, and shows better reversibility and higher cyclic stability compared with pristine Li4Ti5O12, especially at high current rates. When the discharge rate was 0.5C, the Li4Ti5O12−x Br x (x =0.2) sample presented the excellent discharge capacity of 172mAhg−1, which was very close to its theoretical capacity (175mAhg−1), while that of the pristine Li4Ti5O12 was 123.2mAhg−1 only.
Core–shell structure carbon coating Fe3O4 nanoparticles are prepared by a two-step method. The crystalline structure and the electrochemical performance of the prepared samples are investigated. The results indicate that a uniform and continuous carbon layer is formed on the surface of Fe3O4 nanoparticles. The core–shell structure Fe3O4/C nanoparticles show a high initial discharge capacity of 1546mAhg−1 and a specific stable discharge capacity of about 800mAhg−1 at 0.5C with no noticeable capacity fading up to 100 cycles.
Li3V2(PO4)3 cathodes were prepared by applying a carbon coating and Y substitution using a rheological phase reaction process. X-ray diffraction was used to observe the structural properties of the synthesized powders. The presence of the carbon coating was confirmed by transmission electron microscopy and thermogravimetric analysis. The Y-doping amount plays a key role on the structure and electrochemical performance of Li3V2(PO4)3. The Li/Li3Y0.03V2(PO4)3/C cell displayed a discharge capacity of 158.8 mAh g−1 between 3.0 and 4.3 V versus Li at a current density of 0.1 C, which is ~30 mAh g−1 higher than that of the undoped Li3V2(PO4)3/C composites. The capacity retention was found to be 93.9 % after 50 cycles and the capacity of Li3Y0.03V2(PO4)3/C stayed around 100 mAh g−1 at a current density of 100 mA g−1.
Stoody Company, a leader in the design and manufacture of hardfacing and joining welding electrodes, has announced the release of its 1.6 mm (1/16 in.) 160 DM nickel tungsten carbide hardfacing wire. This cast/macrocrystalline tungsten carbide wire,Stoody 160 DM, offers superior wear resistance, especially in fine particle slurry applications. The evenly dispersed macrocrystalline particles are supported by a tough nickel-silicon-boron matrix. Applications include process pipe I.D. cladding, oil field stabilizers, mill hammers, and various types of earth cutting drill bits.
Nitrogen-doped urchin-like Fe3O4@C composites are successfully fabricated via a facile hydrothermal process and subsequent carbonization. Urchin-like hydroxyferric oxide (α-FeOOH) is used as a template and coated by polydopamine (PDA) to form α-FeOOH@PDA. Under high temperature and argon atmosphere, urchin-like Fe3O4 with N-doped carbon shell (Fe3O4@C-N) are finally formed. In the electrochemical test, N-doped carbon shell can form stable solid electrolyte interface (SEI) layer, reduce initial capacity loss and improve the reversibility of Fe3O4 for Li ion storage. Compared with naked Fe3O4 nanospheres, Fe3O4@C nanospheres and urchin-like Fe3O4@C composites, the urchin-like Fe3O4@C-N composites display excellent electrochemical performance. The as-prepared Fe3O4@C-N-20-600 shows a reversible specific capacity of 800mAhg−1 after 100 cycles at 500mAg−1. The significant electrochemical property improvements of urchin-like Fe3O4@C-N composites are attributed to the unique urchin-like structure and the N-doped mesoporous carbon shell. Such a simple and scalable route to construct N-doped carbon encapsulated core-shell structure may be further extended to other high capacity anode and cathode materials.
We investigated the performance of children with developmental dyslexia on a visual line bisection task. Dyslexic children did not show the overestimation of the left visual field (pseudoneglect) characteristic of normal adult vision. These results suggest that children with developmental dyslexia present selective deficits in visual attention, probably involving neural structures located in the right posterior parietal cortex.
Transport through ionic conducting membranes is examined. An equation describing the chemical potential, μ s , of electrically neutral species, s, in the membrane is derived in terms of ionic and electronic currents, and ionic and electronic transport resistances. It is shown that the μ s in the membrane need not be mathematically bounded by the values at the two electrodes (reservoirs) if the ionic and the electronic currents through the membrane are in the same direction. Conditions could develop under which the μ s in the membrane may exceed the thermodynamic stability of the membrane even when exposed to stable conditions at the two electrodes. It is shown that during charging, chemical potential of lithium, μ Li, in the electrolyte of a lithium-ion battery may exceed that corresponding to pure lithium thus causing lithium precipitation and/or reaction with the electrolyte. It is also shown that in a lithium ion battery pack containing several cells, degradation may occur during discharge due to cell imbalance. In unbalanced cells, the SEI layer may form at both the anode/electrolyte and the cathode/electrolyte interfaces. A bi-layer separator comprising an electronic conductor and an electronic insulator is proposed for improved stability of lithium batteries.
The distribution of Fe3+ and Ni3+ impurities and the electrochemical performance of LiCoO2 electrodes were examined. Commercial LiCoO2 powders supplied by Aldrich were used. The electrochemical performance of LiCoO2 was modified by rotor blade grinding of LiCoO2 followed by thermal treatment. Structural information on Fe3+ and Ni3+ impurities was obtained using both conventional X-band and high-frequency electron paramagnetic resonance spectroscopy (EPR). It was found that Fe3+ occupies a Co-site having a higher extent of rhombic distortion, while Ni3+ is in a trigonally distorted site. After rotor blade grinding of LiCoO2, isolated Fe3+ ions display a tendency to form clusters, while isolated Ni3+ ions remain intact. Re-annealing of ground LiCoO2 at 850°C leads to disappearance of iron clusters; isolated Fe3+ ions are recovered. The electrochemical performance of LiCoO2 was discussed on the basis of isolated and clustered ions.
The rate performances of four mixed conductive electrodes (Li4/3Ti5/3O4, LiFePO4, LiCoO2 and LiCo1/3Ni1/3Mn1/3O2) were investigated using galvanostatic charge/discharge, electrochemical impedance Spectroscopy (EIS) and galvanostatic intermittent titration (GITT). These four electrode materials can be roughly divided into two groups according to the structure change during Li intercalation/extraction, i.e. the phase transition materials (Li4/3Ti5/3O4 and LiFePO4) and mixed phase transformation and solid solution materials (LiNi1/3Mn1/3Co1/3O2 and LiCoO2). Both the ionic conductivity and phase transition kinetics have a strong impact on the rate capability of the electrode material in addition to the generally accepted factors such as particle size and electronic conductivity. The rate capabilities of Li4/3Ti5/3O4 and LiFePO4, which have an extended flat region in the charge/discharge curves, mainly depended on their phase transition kinetics. The rate performance of the solid solution materials were controlled by the ionic conductivity, with some influence from the electronic conductivity.
Overdischarge effects on cycle-life and thermal stability of a commercially available Li-ion cell (rated at 780mAh) were investigated. Cells were overdischarged and kept at 2.0, 1.5, 1.0, 0.5 or 0.0V for 72h (3 days) and then cycled five times (discharge to 3.0V at 0.4A and charged to 4.2V at 0.8A). This process was repeated five times. The cells overdischarged between 2.0 and 0.5V experienced irreversible capacity losses of 2–16%. The same cells lost between 8 and 26% more capacity after they were cycled 100 times between 4.2 and 3.0V at 0.8A. Behavior of the cells overdischarged to 0.0V was unpredictable. Some cells lost nearly 65% of their initial capacities after 15 days of being kept at 0.0V, and others failed in different stages of overdischarging to 0.0V. Overdischarging to 0.5V had minimal effects on thermal stability, overcharge performance and a.c. impedance, but led to considerable swelling of the cells. Overdischarge to 0.0V caused cell thickness and a.c. impedance to increase by ∼70 and 250% of their initial values, respectively. This article addresses concerns that overdischarging of Li-ion cells below 1.5V may cause capacity losses and/or thermal stability changes which could impact tolerance to abuse conditions.
In the recent years, there has been a growing interest in research community towards the application of smart materials for bio-medical structural health monitoring. Amongst the smart materials, directly bonded piezo sensors (DBPS), based on the electro-mechanical impedance (EMI) technique, have been successfully employed for the above purpose. The principle behind the EMI technique is that high frequency excitations (typically > 30 kHz) generated by a surface bonded PZT patch are used to detect changes in structural drive point impedance caused by cracks or any other type of damage. Bone healing and damage have been shown to be successfully monitored using the DBPS. However, in most of the diagnostic cases of live human and animal subjects, directly bonding a PZT patch is always an irritant or hazard for a live subject. To circumvent direct bonding, the authors have developed and experimentally demonstrated a non-bonded piezo sensor (NBPS) configuration as a good alternative to DBPS while maintaining the effectiveness of measurement well within discernible limits. This paper presents further improvement in the NBPS configuration aiming at autonomous operation of the gripping mechanism using shape memory alloy (SMA) wires. The experiments are performed on replicas of femur bone in healthy and osteoporosis state. This paper shows the effective use of SMA clamping for bone identification and its damage assessment in comparison to earlier mechanical gripping using jubilee clamps. This paper also covers impedance based identification applied to SMA and clamp based NBPS configurations. In place of raw admittance signatures, effective drive point impedance is utilized for the purpose of bone diagnostics which provides a more realistic assessment of the condition of bone.
Publisher Summary Precipitation is a widely used industrial process. It is also a very popular laboratory technique, especially in analytical chemistry, and the literature on this aspect of the subject is voluminous. Precipitation plays an important role not only in chemistry but also in metallurgy, geology, physiology, and other sciences. In the industrial field, the manufacture of photographic chemicals, pharmaceuticals, paints and pigments, polymers, and plastics utilizes the principles of precipitation. For the production of ultrafine powders, precipitation may be considered a useful alternative to conventional crystallization, followed by milling. The term “precipitation” very often refers to nothing more than fast crystallization, although sometimes it also implies an irreversible process—for example, many precipitates are virtually insoluble substances produced by a chemical reaction, whereas the products of most conventional crystallization processes can usually be redissolved if the original conditions of temperature and solution concentration are restored.
Forest and nature managers are confronted with an increasing number of tourists visiting National Parks, nature reserves and forest areas. Not all tourists, however, have or prefer the same experiences. In this study, we develop a theory on the nature of tourist experiences by proposing tourism as a way of distancing oneself from everyday reality, conceptualised in terms of out-there-ness. Experience is conceived of as conscious awareness, embedded in relatively stable mental structures, and manifested as a dynamic precondition for immediate responses to tourist practices. These preconditions are theoretically translated into different modes of experience, which are empirically tested. The results show that the theoretical modes of the experience of out-there-ness have considerable empirical support. We present these results in relation to practical applicability for policy-making, planning and design.
Nanoflakes of the cobaltous oxide as a thin film were deposited from a 100mM cobalt (II) nitrate solution potentiostatically at −1000mV (vs. Ag/AgCl) onto a platinum electrode surface. Surface morphology of the cobaltous oxide was studied by surface microscopy techniques (SEM, AFM and STM) and the electrochemical behavior was evaluated in alkaline solution using cyclic voltammetry and electrochemical impedance spectroscopy. Using cyclic voltammetry, the electron-transfer coefficient and the apparent charge-transfer rate constant of various redox transitions were determined. The cobaltous oxide electrode represented prominent electrocatalytic activity toward the mediated electrooxidation of ascorbic acid, glucose and methanol. In the Nyquist diagrams, different time constants appeared with relation to different physicochemical processes.
In this work, CuO/n-Si and AuNPs-decorated CuO/n-Si heterojunction photodetectors were fabricated by deposition of CuO nanoplatelets and Au nanoparticles NPs decorated CuO nanoplatelets on silicon substrates by laser ablation in methanol. Atomic force microscope AFM, scanning electron microscope SEM and transmission electron microscope TEM were used to study the structural and surface morphology of CuO and AuNPs–CuO. The electrical properties showed that the CuO/Si and AuNPs decorated-CuO/Si showed rectifying behavior. The maximum values of quantum efficiency were about 41 and 78% at 700 nm for CuO/Si and AuNPs–CuO/Si photodetectors, respectively. The I–V characteristics of the photodetectors were measured under UV light.
Coaxial architectures consisting of metal oxide and carbon nanotube are promising for many energy applications due to their synergetic interaction. The engineering and development of coaxial structures through a simple approach are highly desirable but remain a challenge. Herein, we present a general and facile ethylene glycol bath approach to fabricate coaxial architectures in which the metal oxide component is sandwiched by carbon nanotube and amorphous carbon. These unique architectures can serve as efficient electrode for lithium storage. The internal carbon nanotube allows rapid electron transport, while the external amorphous carbon acts as flexible buffer to accommodate volume variation upon lithium uptake. When evaluated in lithium cells, the carbon nanotube and iron oxide coaxial material exhibits a remarkable electrochemical lithium storage. It affords a capacity of 1083 mAh g−1 over 60 cycles, and retains 529 mAh g−1 at a high rate of 5 A g−1, drastically outperforming the pure iron oxide counterpart. This facile approach is in principle applicable to constructing other coaxial electrodes, and thus holds great potential in the manipulation of battery materials for lithium storage application.
Background and Overview The use of electronic cigarettes (e-cigarettes) is a rapidly growing trend throughout the United States. E-cigarettes have been linked to the risk of causing explosion and fire. Case Description Data are limited on the associated health hazards of e-cigarette use, particularly long-term effects, and available information often presents conflicting conclusions. In addition, an e-cigarette explosion and fire can pose a unique treatment challenge to the dental care provider because the oral cavity may be affected heavily. In this particular case, the patient’s injuries included intraoral burns, luxation injuries, and alveolar fractures. Conclusions and Practical Implications This case report aims to help clinicians gain an increased knowledge about e-cigarette design, use, and risks; discuss the risk of spontaneous failure and explosion of e-cigarettes with patients; and understand the treatment challenges posed by an e-cigarette explosion.
The electrochemical properties of AlPO4-coated LiCoO2 cathodes prepared in a water or ethanol solvent were characterized with the view of stabilizing LiCoO2 at charge-cutoff voltages of 4.6 and 4.8V. Under the influence of the AlPO4 crystallinity, the coated LiCoO2 prepared in ethanol had better capacity retention than those prepared in water. This enhancement also correlated with the improved suppression of Li-diffusivity decay in the coated cathode from the ethanol compared to that from water. In addition, the differential scanning calorimetry (DSC) results of the AlPO4 nanoparticle-coated LiCoO2 with ethanol showed an enhanced thermal stability.
Vanadium oxide prepared by plasma-enhanced chemical vapor deposition was cycled in different voltage ranges in a lithium battery. Electrochemical cycling results show a surprisingly low irreversibility during the first discharge and good stability for close to 1000 cycles between 4 and 0V. Raman spectroscopy results indicate that a major structural transformation takes place when the films are cycled down to 1.8V, after which the structural features remain intact even after cycling to 0V. Degradation of the electrode only occurs after extended cycling.