batterydata/paper-abstracts huggingface dataset:
Analysis of phase transformation processes observed in most hydrogen-absorbing materials (pure metals, alloys or compounds) is still a matter of active research, in view of electrochemical or chemical hydrogen storage applications. Most metal hydride systems present a large and irreducible hysteresis, indicating that non-linear phenomena are taking place during hydrogen sorption/desorption reactions. Investigation of hydriding kinetics therefore requires non-harmonic spectroscopies to fulfill the requirements of linearity and time invariance imposed by the theory of systems. The purpose of this paper is to report on the insertion of atomic hydrogen into a palladium foil. The process is analyzed using electrochemical (the electrolyte is the source of hydrogen) and pneumato-chemical (the gas phase is the source of hydrogen) experimental spectroscopies. Pneumato-chemical impedance spectroscopy (PIS) provides additional information to electro-chemical impedance spectroscopy (EIS) since (i) there is no electrolyte and no electrified interface; (ii) experiments can be performed over long periods of time, without any pollution (closed systems); (iii) there is no parasite reaction such as hydrogen evolution encountered in electrochemical experiments; (iv) the temperature range of investigation is larger; (v) there is no kinetic limitations on the electrolyte side of the interface. Results obtained in single and two-phase domains of the model PdH system, using both EIS and PIS spectroscopies, are reported and discussed. Surface and bulk microscopic rate parameters are compared.
The Industrial Materials Institute is dedicated to assisting Canadian industry by conducting R & D in the areas of materials formulation and processing — including some leading-edge work in PM. Joe Capus found out more…
A rough coating structure of CeO2@Li[Ni0.5Co0.2Mn0.3]O2 can be formed via a wet chemical method. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectroscope (EDS) are carried out to study the structures and morphologies, which all confirm the existence of CeO2 coating layer on the Li[Ni0.5Co0.2Mn0.3]O2 surface. The 2 wt.% CeO2-coated Li[Ni0.5Co0.2Mn0.3]O2 can deliver 97.4 mAh g−1 at 10C and 59.2 mAh g−1 at 20C after 100 cycles in the voltage range of 2.8–4.6 V, while the pristine Li[Ni0.5Co0.2Mn0.3]O2 can deliver only 23.5 mAh g−1 at 10C and 9.0 mAh g−1 at 20C. The discharge capacities of CeO2-coated Li[Ni0.5Co0.2Mn0.3]O2 samples at high discharge rates are much higher than those of the pristine Li[Ni0.5Co0.2Mn0.3]O2. Meanwhile, the CeO2-coated Li[Ni0.5Co0.2Mn0.3]O2 sample shows better rate performance at different rates. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements reveal that the improved electrochemical performance can be attributed to the reduced interfacial polarization and stabilized structure of Li[Ni0.5Co0.2Mn0.3]O2 by CeO2 coating. Transmission electron microscope (TEM) is applied to analyze the role of CeO2 coating layer on the long cycling life.
In this work, we have successfully synthesized a novel imidazolium polymeric ionic liquid containing polyhedral oligomeric silsesquioxane and use it as host polymer to develop novel solid polymer electrolytes with high room temperature ionic conductivity, good cycle performance and rate capability. The polymeric polyhedral oligomeric silsesquioxane ionic liquids based solid polymer electrolytes exhibit highest room temperature ion conductivity up to 4.82 × 10−4 S cm−1 and outstanding electrochemical stability up to 5 V relative to Li+/Li. Moreover, the Li/LiFePO4 cells containing the novel solid polymer electrolytes exhibit excellent cycle performance and rate capability, delivering an initial discharge capacity of about 151.8 mAh g−1 at a rate of 0.1 C at room temperature with excellent capacity retention after 100th cycles.
Galvanostatic deposition of tartrate–doped polypyrrole (PPy) is carried out on platinum foil in acetonitrile solution with tartaric acid, tetrabutylammonium tetrafluoroborate and Triton-X 100 for supercapacitor studies. The effect of substrate is studied by comparing the results obtained by using platinum, stainless steel and pencil graphite electrodes. The capacitive performance of the coatings are evaluated in an H2SO4/water medium by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge methods. Based on the charge–discharge results obtained, the tartrate–doped PPy coatings represent a high specific capacitance of 794Fg−1 (areal capacitance of 238mFcm-2) and a high energy density of 105Whkg-1 on pencil graphite electrode, and a high power density of 36.3kWkg-1 on 316Ti stainless steel electrode. High values may be attributed to the incorporation of tartaric acid via hydrogen bonding, and/or tartrate anion as dopant together with the tetrafluoroborate anion. Besides, Triton X100 provides high porosity and therefore high surface area.
Ubiquitous healthcare is the service that offers health-related information and contents to users without any limitations of time and space. Especially, to offer customized services to users, the technology of acquiring context information of users in real time is the most important consideration. In this paper, we researched wearable sensors. We proposed the ontology driven interactive healthcare with wearable sensors (OdIH_WS) to achieve customized healthcare service. For this purpose, wearable-sensor-based smart-wear and methods of data acquisition and processing are being developed. The proposed system has potential value in healthcare. A smart wear using wearable sensors is fabricated as a way of non-tight and comfortable style fitting for the curves of the human body based on clothes to wear in daily life. The design sample of the smart wear uses basic stretch materials and is designed to sustain its wearable property. To offer related information, it establishes an environment-information-based healthcare ontology model needed for inference, and it is composed of inside-outside context information models depending on the users’ context. The modeling of the proposed system involved combinations of information streams, focusing on service context information. With the proposed service inference rules, customized information and contents could be drawn by the inference engine. In the established OdIH_WS, real-time health information monitoring was achieved. The results of system performance and users’ satisfaction evaluations confirmed that the proposed system is superior to other existing systems.
The aim of this study was to assess the association between physical fitness (PF) and energy and nutrient intake in Spanish older adults.
Owing to the passivation behavior of iron anode, alkaline iron-based rechargeable batteries usually show very poor high rate performance (below 1.0C), which seriously restricts their widespread commercial deployment. In this work, for the first time, we demonstrate that sublimed sulfur can be used as a novel, cheap and effective anode additive to significantly enhance the high-rate performance of iron-based battery. Influences of S additive on the electrochemical performances of iron anode are investigated systemically. Moreover, the possible mechanism of sublimed sulfur is further investigated. It is interestingly discovered that the adding method and adding content of S has greatly affected the final performance of the iron electrode. The Fe3O4 +10 wt.%S mixing electrode can be charged at 2C and discharged at the rate as high as 5C with a discharge capacity of ～430 mAh g−1. The significant enhancement of high rate performance can be ascribed to that sublimed sulfur can not only provide sustained supply of sulfur ions during cycling but also act as a pore-former to modify the porosity of iron electrode to form a beneficial porous electrode structure. Therefore, it is believed that sublimed sulfur is a promising, highly efficient anode additive for advanced iron-based batteries.
“Finding the Invisible Defect” is the theme for 2011 at the premier event for the microelectronics failure analysis community. The ISTFA technical symposia, user groups, education opportunities, and the largest equipment exposition in the industry make ISTFA the best place to learn, network, and further your career.
This research study examined university students’ evaluation of teaching at an English preparatory school. Twelve students who participated in the study were chosen as a consequence of theoretical sampling because they repeated the intermediate level twice and were believed to give valuable information regarding the challenges encountered in the program. Aims of the study were to: (1) demonstrate quality assurance at program implementation level, (2) get feedback from students on the appropriateness of activities for their learning needs, (3) get students to reflect on their language skills development and identify what they still need to learn that could be useful for the improvement of teaching, (4) raise awareness and persuade students to engage with the opportunities for learning beyond classroom and (5) negotiate emphases for the remainder of the program. Participants were asked to comment on and evaluate the educational quality, course objectives, performance of their instructor, their learning, achievement and progress, course materials, learning support they received, role of information and communication technology, and assessment procedures. Data was collected by Students’ Evaluation of Educational Quality Instrument (SEEQ), focus group interviews and field notes. Findings revealed certain action points for the development of the English language teaching program.
EaglePicher Inc (EPI), and its US subsidiaries, including EaglePicher Filtration & Minerals Division, have concluded their Chapter 11 restructuring process.
Linear sweep voltammetry (LSV) is a well-known tool for electrochemical investigations. Different aspects on the use of LSV in the study of an intercalation electrode in the rechargeable lithium battery system have been studied. Mathematical models were used to simulate voltammetry responses for an intercalation material influenced by solid phase diffusion, charge transfer and IR-drop. It was shown how the peak potential and the peak current density vary with sweep rate for different rate determining processes. The simulations show that finite and semi-infinite diffusion is relatively easy to distinguish and also, these two processes behave differently from processes influenced by charge transfer and an external IR-drop. However, the separation of charge transfer and IR-drop is difficult. The use of the convolution sweep voltammetry method was also investigated. It was found that finite diffusion and a non-zero initial concentration limit the applicability in these systems.
This paper outlines a method for optimizing the design of a lithium-ion battery pack for hybrid vehicle applications using a hybrid numerical optimization method that combines multiple individual optimizers. A gradient-free optimizer (ALPSO) is coupled with a gradient-based optimizer (SNOPT) to solve a mixed-integer nonlinear battery pack design problem. This method enables maximizing the properties of a battery pack subjected to multiple safety and performance constraints. The optimization framework is applied to minimize the mass, volume and material costs. The optimized pack design satisfies the energy and power constraints exactly and shows 13.9–18% improvement in battery pack properties over initial designs. The optimal pack designs also performed better in driving cycle tests, resulting in 23.1–32.8% increase in distance covered per unit of battery performance metric, where the metric is either mass, volume or material cost.
Lithium–sulfur (Li–S) batteries are known for their high energy density but suffer from poor cycling performance due to severe dissolution of the polysulfides (PSs) in liquid electrolyte and their shuttle effect. Effectively anchor the PS should combine the physical and chemical adsorption. However, most of the current studies are focused on confining the PS mobility by physical adsorption alone. Herein, chemical adsorption of the PS is emphasized in a special cell with functionalized graphene adsorbers. Both the experimental and calculated results show that functional groups containing C, N, O and P atoms are beneficial for immobilizing the PSs via chemical bonding, such as C–S, O–S, P–S. Such cells deliver a reversible capacity as high as 1218mAhg−1 and cycle stably by solely applying the chemical adsorption, comparable to the current reports mostly based on physical adsorption. Our findings enrich the fundamental understanding of the chemical adsorption of the PS and shed light on the design of sulfur electrodes.
NaxCayCoO2 (0.45 ≤ x ≤ 0.64, 0.02 ≤ y ≤ 0.10) is synthesized via a solid-state method and examined as a cathode material to improve the cyclability of sodium ion batteries (SIBs). The substitution of one Ca2+ for two Na+ does not alter the P2-phase of undoped Na0.73CoO2, accompanying the continuous contraction of the unit cell volume with Ca-doping. The existence of Ca2+ in the prismatic sites between CoO6 slabs also affects the phase transition behaviors during charge–discharge (C–D). The suppression of Na+-vacancy ordering, ascribed to the immobility of Ca2+ in NaxCayCoO2, leads to continuous changes of the cell voltages with no abrupt voltage drops during C–D. The reduced cell dimension and the mitigation of distinctiveness between biphasic and solid-solution domains during C-D improve the cyclability of NaxCayCoO2 in SIBs. As an example, the negligible capacity fading in Na0.60Ca0.07CoO2 during 60 cycles (0.07 mAh g−1 cycle−1) is contrasted with a substantial decrease in the reversible capacity of Na0.73CoO2 (0.56 mAh g−1 cycle−1). Furthermore, a slower Na+ diffusion of NaxCayCoO2 in Na+-vacancy ordering regions, is sufficiently offset by a more rapid diffusion in all the other regions, which results in an improved rate performance. The platform presented here (multi-valent cation substitution for Na+) could be utilized in other layered cathode materials to improve the electrochemical performance of SIBs.
This paper reports on an investigation in which several standard Microelectromechanical Systems (MEMS) elements consisting of thermal actuators, inchworm drives, and comb drives were subjected to vibration loading representative of the environment seen in space applications. Finite-element analysis of the MEMS devices showed that sufficient margins existed under the expected environmental loading. Vibration testing, however, resulted in several failures in the devices, and analysis showed that progressive failure initiated from large local displacements. Debris transport and entrapment was another source of failure leading to shorting of thermal actuators. The results illustrate the importance of debris control and packaging design for reliable MEMS operation. Suggestions for improving the reliability of MEMS devices through practical layout and packaging guidelines are made.
Al-doped Li2ZnTi3O8 in the form of Li2ZnTi3 − x Al x O8 (0⩽ x ⩽0.2) compounds are successfully synthesized by a simple and facile high temperature solid-phase reaction. The characteristics of Li2ZnTi3 − x Al x O8 are examined by X-ray diffraction, scanning electronic microscopy, transmission electron microscopy and laser particle size analyzer, while the electrochemical performances including galvanostatic charge–discharge testing, cyclic voltammetry, and electrochemical impedance spectroscopy were also investigated. It is shown from the structure analysis that Li2ZnTi3 − x Al x O8 (x =0, 0.05, 0.1) has the pure phase structure, but impurity peak of LiAlO2 can be detected when x >0.1. In the voltage range of 0.05–3.0V, Li2ZnTi2.9Al0.1O8 electrode presents the largest initial discharge capacity of 223.1mAhg−1 at 0.1Ag−1. Moreover, the discharge capacities of Li2ZnTi2.9Al0.1O8 after 100 cycles are 173.2, 136.7, 108.6, and 61.4mAhg−1 at 0.5, 1.0, 2.0, and 3.0Ag−1, respectively, which obviously higher than those of un-doped sample. The electrode reaction reversibility and electronic conductivity of pure Li2ZnTi3O8 are enhanced after doping Al (x =0.1). The results revealed that doping Al should be an effective way to improve the cycling performance.
Although the choice of binder is crucial in determining the electrochemical performance and durability of silicon-based electrodes, the underlying mechanisms (e.g., mechanical vs. chemical) are unclear. Here, we report a study of the effects of adhesion vs. cohesion on the electrochemical behavior of silicon nanoparticle/polymeric binder/carbon black (CB) electrodes on copper conductor by multiple techniques. Two types of polymeric binders, polyvinylidene fluoride (PVDF) and sodium alginate (SA), were chosen for this study. The results show that because of a sufficiently strong interface between polymer and the copper current collector, both Si/PVDF/CB and Si/SA/CB composite electrode laminates have sufficient adhesive strength with the Cu conductor to cause cohesive failure within the electrode laminate during peel test. However, the interfacial strength between SA and silicon is significantly higher than that between PVDF and silicon, resulting in stronger cohesion within the Si/SA/CB electrode (e.g., peel strength of 78.3 N/m for Si/SA/CB electrode and 8.7 N/m for Si/PVDF/CB electrode, respectively). With a higher cohesive strength provided by a stronger binder-silicon interface, superior cell performance was ensured for Si/SA/CB electrodes. Hydrogen bonding is likely responsible for the stronger SA-Si interface since neither PVDF nor SA bonds covalently with Si according to chemical analysis.
Background A female patient presented with persistent orofacial pain on the right side for 3 years, attributed to a viral infection. The pain had remained largely pharmacoresistant, reaching a value of 8/10 on the visual analogue scale. Methods The patient underwent varying three different conditions of trancranial direct current stimulation (tDCS). First, the contralateral representational field of the face area of the primary motor cortex (M1) was anodally stimulated for 5 consecutive days for 20 minutes at 1 mA. During the second stimulation condition, 20 minutes cathodal stimulation was applied for 5 consecutive days at 2 mA intensity over the contralateral representational field the face area of primary somatosensory cortex (SI). In the third condition, the hand area of the left M1 was anodally stimulated for 20 minutes at 1 mA intensity for 8 days combined with the oral administration of D-cycloserine. Results With regard the third stimulation condition, a 60% reduction in pain perception was observed toward the end of the stimulation. The patient reported a significant pain relief sensation for up to 6 weeks poststimulation. Conclusions Although this is a pilot exploratory trial in a single patient, our study is a further step toward clinical application of tDCS over the M1 using pharmacologic intervention, to prolong the induced after effect. Furthermore, it demonstrates the potential for repetitive daily stimulation therapy for chronic pain patients.
A new polyaniline (PANI)-coated technique was adopted for a AB5-type alloy (La0.64Ce0.25Pr0.03Nd0.08Ni4.19Mn0.31Co0.42Al0.23) in order to improve its electrochemical and kinetic properties. FE-SEM observation and FT-IR analysis results revealed that the PANI electroless deposited to the surface of alloy particles. Through the PANI-coating the initial discharge capacity increased from 299 to 331mAh/g and the high rate discharge ability (HRD) increased from 8.5 to 45.0% at discharge current density of 1440mA/g. For kinetic properties, linear polarization, EIS, anodic polarization and cyclic voltammetry measurements suggested that charge-transfer resistance decreased and the hydrogen absorption rate of the alloys increased after PANI-coating.
Sulfide glasses have been considered as new anode materials for lithium-ion batteries because their high ionic conductivity (approximately ≥10−4 S/cm) (more than one order of magnitude higher than oxide glasses (approximately ≤10−6 S/cm)) was expected to accelerate Li+ ion insertion into and extraction from anode materials during charge and discharge reactions. This intrinsic property can yield the reversible lithium-alloying reaction by minimizing the aggregation of lithium-alloy phases leading to the improvement of cycling behavior. To examine sulfide glasses as new anode materials, GeS2 glass was chosen for study in this work due to its stability in air-atmospheres. The electrochemical properties of the GeS2 glass were compared with those of the Ge metal and GeO2 glass. The initial insertion of lithium into the GeX2 (X=O, S) glasses leads to the formation of Li2X (X=O, S) phases associated with the irreversible capacity on the first cycle. The improved reversibility of the reaction of lithium with Ge was observed in the Li2S medium rather than Li2O one, which leads to the improvement of cycle performance in the GeS2 glass anode.
Electrochemical impedance spectroscopy (EIS) is a technique widely used to characterize electrochemical systems. While EIS is powerful and simple to use, interpreting EIS experiments is not a straightforward task. Equivalent circuits are by far the most commonly used EIS models. However, these circuits models are not unique. To overcome this issue, the research community has shown increasing interest in distributional methods such as the distribution of relaxation times (DRT), and the recently developed distribution of diffusion times (DDT). The DDT method captures the diffusional timescales of electrode particles, and for this reason, is particularly well suited for the study of the EIS response of batteries and supercapacitors. One major assumption of the DDT method is that the electrodes of these devices are thin. This article generalizes the DDT to electrodes of finite thickness, and this analytical model is termed the non-linear distribution of diffusion times (NL-DDT). The NL-DDT is studied using synthetic data and applying it to actual experiments. The study shows that the NL-DDT can recover the diffusional characteristics as well as the physical properties of the electrodes, including the chemical diffusion coefficient and ionic conductivities.
Due to the capability of CO2 uptake and the high theoretical energy density, Li–CO2 batteries have attracted a great deal of attention as a novel and promising energy storage system which is based on the reversible reaction between lithium and CO2. However, the insulating Li2CO3 formed upon the discharge process, which is difficult to be decomposed during recharge process due to the lack of effective cathode catalyst, leads to the poor cycling performance and huge overpotential of the Li–CO2 batteries. In this work, the Ru nanosheets were directly grown on one side of the three-dimensional nickel foam through a galvanic replacement reaction to form the Ru/Ni electrode, which was further used in the Li–CO2 batteries. The highly dispersed Ru nanosheets in the Ru/Ni cathode effectively promote the decomposition of discharge product Li2CO3 and thus reduce the charge overpotential. Moreover, the typical porous and binder-free Ru/Ni electrode not only has a sturdy construction to suppress the side reaction in the Li–CO2 batteries, but also enables the rapid permeation of CO2 and electrolyte/electron into the active sites of the Ru/Ni electrode. As a result, the Ru/Ni cathode-based Li–CO2 battery exhibits the superior discharge capacity (9502 mAh g−1), good coulombic efficiency (95.4%) and excellent rate performance (3177 mAh g−1 at 500 mA g−1) at the full discharge/charge condition. When operated at the limited capacity of 1000 mAh g−1, this cell can run for over 100 cycles with the charge potential below 4.1 V. The findings provide a snapshot towards improving the reversibility of Li–CO2 batteries by designing the binder-free stable cathodes.