batterydata/paper-abstracts huggingface dataset:
As a first step towards studying pitting corrosion of Zn in deaerated neutral sodium nitrite solutions (pH 6.9), we have reported the results of potentiodynamic polarization and cyclic voltammetry measurements on the passivity and passivity breakdown of Zn in these solutions. Measurements were conducted under the influence of various experimental conditions, complemented by ex situ scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) examinations of the electrode surface. The voltammograms involve active/passive transition prior to the initiation of pitting corrosion as a result of breakdown of the passive film by NO2 − ions. The active region displays one anodic peak due to the formation of ZnO passive film on the anode surface. SEM examinations confirmed the existence of pits on the electrode surface. The potential at which pits initiated (E pit) was determined, together with a pit transition potential (E ptp) that appeared as an abrupt current discontinuity on the reverse potential scan (hysteresis loop), and a protection potential (E prot) that appeared at the end of the hysteresis loop. The value of E pit shifted negatively as either C nitrite or temperature was increased, while it increased with the increase in potential scan rate. The effect of adding some environmentally acceptable inorganic inhibitors, as tungstates, molybdates and silicates (water glass), on the pitting corrosion behaviour of Zn in nitrite solutions has also been studied. The mechanism of inhibition was discussed.
Electrodeposited vanadium oxide has emerged as a potential electrochemical capacitor material due to its attractive initial pseudocapacitive performance. However, it suffers from capacitive degradation upon charge/discharge cycling in aqueous electrolytes. Possible degradation mechanisms, including material dissolution, are discussed. To test these possible mechanisms, an agar gel coating is deposited on the films to reduce mass transport between the electrode/electrolyte interface. The electrochemical cycling behavior of vanadium oxide films with various surface treatments is investigated at different pH. Quantitative compositional analysis and morphological studies provide additional insight into the mechanism responsible for capacitive degradation.
A facile templating method was used to fabricate a Magnetite (Fe3O4) nanotubes coated carbon cloth electrode as anode for lithium ion batteries in this work. In hope of achieving high-performance and stable electrode, ZnO nanorods were first electrodeposited and subsequently used as sacrificial templates for synthesis of Fe3O4 nanotubes arrays. According to structural analysis, this strategy led to a uniform nanotubes-like coating attached on interwoven carbon fiber of the three-dimensional (3D) carbon cloth. Unexpectedly, it was found that the nanotube structure was assembled from numerous nanoparticles that formed up a hierarchical structure with 3D arrangement inherited from carbon cloth substrate. The as-prepared electrode delivered excellent rate capability, giving a maximal specific capacity of ⿼930mAhg-1 at 2Ag-1 but a relatively poor cycling retention of 73% after 200 cycles. This is attributed to the severe agglomeration of nanocrystalline Fe3O4 particles upon repeated cycling, revealing the fact that small particles accounting for high rate performance might in turn undermine the cycling stability.
Sodium-ion batteries (SIBs) have attracted extensive interests for the large electronic equipment. Increased size of the Na-ion is the primary factor of its slow diffusion in the bulk, which poses big challenges for the manufacturing of active materials suitable for SIBs. Here, we present a set of porous Co0.85Se/N-doped carbon (Co0.85Se/NC) composites with an excellent ratio (above 85%) of surface/near-surface pseudocapacitance Na-ion phenomena. When cycled at 100 mA g−1, the Co0.85Se/NC-1.0 anode delivers an ultrahigh initial discharge capacity of 713 mAh g−1. During the 100 cycles under 1000 mA g−1, its reversible specific capacity is up to 509 mAh g−1. Besides, the anode also presents a robust rate performance with a limited capacity loss between 100 and 5000 mA g−1. Especially, a capacity of 382.8 mAh g−1 is still delivered at 5000 mA g−1. Among the various cobalt selenide-based materials, such an outstanding Na+ storage capacity and rate performance contribute the Co0.85Se/NC composites to be a promising candidate of SIBs.
The anodic oxidation behaviour of pure aluminium (Al) in propylene carbonate was investigated using electrochemical measurements, microscopic observations, elemental and gravimetric analyses. The formation and growth of the oxide were observed on the surface of Al in the early stage of anodizing. Further anodic oxidation led to the breakdown of a part of the oxide film, resulting in simultaneous pitting corrosion because of the limitation of mass transfer in the oxide layer.
The room temperature Na-ion secondary battery has been under focus lately due to its feasibility to compete against the already well-established Li-ion secondary battery. Although there are many obstacles to overcome before the Na-ion battery becomes commercially available, recent research discoveries corroborate that some of the cathode materials for the Na-ion battery have indeed indisputable advantages over its Li-ion counterparts. In this publication, a comprehensive review of layered oxides (NaTMO2, TM = Ti, V, Cr, Mn, Fe, Co, Ni, and a mixture of 2 or 3 elements) as a viable Na-ion battery cathode is presented. Single TM systems are well characterized not only for their electrochemical performance but also for their structural transitions during the cycle. Binary TM systems are investigated in order to address issues regarding low reversible capacity, capacity retention, operating voltage, and structural stability. As a consequence, some materials already have reached an energy density of 520 mW h g−1, which is comparable to that of LiFePO4. Furthermore, some ternary TM systems retained more than 72% of their capacity along with over 99.7% Coulombic efficiency for 275 cycles. The goal of this review is to present the development of Na layered oxide materials in the past as well as the state of the art today in order to emphasize the compatibility and durability of layered oxides as powerful candidates for Na-ion battery cathode materials.
H2 is an ideal energy carrier because it has a high energy density, and it can be easily stored, transported, and readily used to power electrical devices. Like photosynthesis, where photons are converted into energy-rich molecules, sunlight energy can be converted into H2 and O2 using photoelectrochemical water splitting cells (PECs). Despite the fact that silicon is considered one of the most attractive semiconductors for manufacturing photoelectrodes, its use is currently limited by its low activity and its instability in aqueous solutions. Herein, we report on surprisingly stable Si-based photoanodes, fabricated by simple aqueous electrodeposition, which results in the partial (<20%) coating of the Si surface with dispersed Ni nanoparticles (NPs). We show that photoelectrochemical activation considerably improves their performance by generating a high-activity catalytic shell around the Ni NPs. In addition, we demonstrate the stability of the photoanodes under various conditions in highly corrosive alkaline solutions in operation and in inactivity. The protection in operation is explained by anodic passivation, which generates a stabilizing SiOx layer. In contrast, the stability when no polarization is applied is unexpected because most of the Si, highly prone to etching, is in contact with the very corrosive aqueous phase. The experimental data allow us to propose a mechanism explaining this effect.
Children with Asperger's syndrome show deficits in social functioning while their intellectual and language development is intact suggesting a specific dysfunction in mechanisms mediating social cognition. An action observation/execution matching system might be one such mechanism. Recent studies indeed showed that electrophysiological modulation of the “Mu-rhythm” in the 10–12 Hz range is weaker when individuals with Asperger's syndrome observe actions performed by others compared to controls. However, electrophysiological studies typically fall short in revealing the neural generators of this activity. To fill this gap we assessed magnetoencephalographic Mu-modulations in Asperger's and typically developed children, while observing grasping movements. Mu-power increased at frontal and central sensors during movement observation. This modulation was stronger in typical than in Asperger children. Source localization revealed stronger sources in premotor cortex, the intraparietal lobule (IPL) and the mid-occipito-temporal gyrus (MOTG) and weaker sources in prefrontal cortex in typical participants compared to Asperger. Activity in premotor regions, IPL and MOTG correlated positively with social competence, whereas prefrontal Mu-sources correlated negatively with social competence. No correlation with intellectual ability was found at any of these sites. These findings localize abnormal Mu-activity in the brain of Asperger children providing evidence which associates motor-system abnormalities with social-function deficits.
The surface of a Li[Ni0.8Co0.15Al0.05]O2 cathode material was coated by a 50-nm thick AlF3 layer using a simple dry coating process. Although the initial discharge capacity of pristine and AlF3-coated Li[Ni0.8Co0.15Al0.05]O2 was nearly same, the AlF3-coating significantly improved the electrochemical performances of Li[Ni0.8Co0.15Al0.05]O2 in a full cell configuration (graphite anode), especially at an elevated temperature (55 °C). Furthermore, the AlF3-coated Li[Ni0.8Co0.15Al0.05]O2 had better thermal stability than the pristine electrode. The improved electrochemical performance likely arose from the AlF3 coating layer which may have retarded the transition metal dissolution from HF attack. Electrochemical impedance spectroscopy and transmission electron microscopy provided direct evidence that the AlF3 coating layer suppressed the increase in charge transfer resistance and cathode material pulverization during cycling.
Li3V2(PO4)3/C cathode material is synthesized by a carbon-thermal reduction method using polyvinyl alcohol as carbon source at 700°C. The Li3V2(PO4)3/C electrode presents a high initial discharge capacity of 84.3, 111.1, 128.7, 129.2 and 132.1mAhg−1 at −20, 0, 25, 40 and 65°C between 3.0 and 4.3V, and 118.9, 132.1, 187.6, 180.3 and 172.2mAhg−1 between 3.0 and 4.8V at 0.1C, respectively. However, the electrode only delivers small discharge capacities at −20°C at 10C rate. The capacity fade at low temperatures is mainly attributed to the reduced ionic and electronic conductivity of the electrolyte, the increased impendence of solid electrolyte interface (SEI) and charge-transfer resistance on the electrolyte–electrode interfaces. At higher temperatures, the capacity increases with increasing temperature between 3.0 and 4.3V, but decreases between 3.0 and 4.8V. In the potential range of 3.0–4.8V, the larger crystal structural distortion and non-uniformity of SEI layer at high temperatures may be the main reasons for the capacity loss.
An effective optimum charging technique for lithium ion batteries using a universal voltage protocol (UVP) that can accommodate cell aging is presented here. This charging method demands less learning to varying state-of-health (SOH) conditions with potential to improve charging efficiency and cycle life. The simplicity of UVP makes the implementation easier than the conventional constant current–constant voltage (CC–CV)-based methods. Here, the mathematical formulation, optimization targets (e.g. minimal time) and constraints (terminal voltages and other instrumental and cell electrochemistry-limited ones) are explained from the protocol design considerations. An equivalent circuit model was used and its parameters derived from the analysis of test data, which could yield a nonlinear varying current profile (VCP) by simulation and a genetic algorithm-based optimization. Both UVP and VCP were used in the validation to illustrate better charging efficiency and capacity retention, which showed a much improved cycle life.
Smart healthcare systems require recording, transmitting and processing large volumes of multimodal medical data generated from different types of sensors and medical devices, which is challenging and may turn some of the remote health monitoring applications impractical. Moving computational intelligence to the network edge is a promising approach for providing efficient and convenient ways for continuous-remote monitoring. Implementing efficient edge-based classification and data reduction techniques are of paramount importance to enable smart healthcare systems with efficient real-time and cost-effective remote monitoring. Thus, we present our vision of leveraging edge computing to monitor, process, and make autonomous decisions for smart health applications. In particular, we present and implement an accurate and lightweight classification mechanism that, leveraging some time-domain features extracted from the vital signs, allows for a reliable seizures detection at the network edge with precise classification accuracy and low computational requirement. We then propose and implement a selective data transfer scheme, which opts for the most convenient way for data transmission depending on the detected patient’s conditions. In addition to that, we propose a reliable energy-efficient emergency notification system for epileptic seizure detection, based on conceptual learning and fuzzy classification. Our experimental results assess the performance of the proposed system in terms of data reduction, classification accuracy, battery lifetime, and transmission delay. We show the effectiveness of our system and its ability to outperform conventional remote monitoring systems that ignore data processing at the edge by: (i) achieving 98.3% classification accuracy for seizures detection, (ii) extending battery lifetime by 60%, and (iii) decreasing average transmission delay by 90%.
Chemical composition, physical characteristics and structural features of a natural FeS2 powder and a synthetic FeS2 sample were correlated with their specific discharge capacities in lithium cells. The levels of impurity elements, primarily present as second-phase oxides and sulfides, were significantly higher in the natural FeS2 than in the synthetic sample. These impure second-phases were electrochemically inactive, and they did not have any significant effects on the discharge of Li/FeS2 cells. Trace amounts of impurity elements were detected in solid solution of FeS2 pyrite and the pyrite structure was nearly ideal for both the natural and synthetic samples. A sulfur-deficient pyrrhotite FeS1.3 phase was found in the center of some large synthetic FeS2 particles, which was electrochemically active at 1.5 V versus lithium. Optical microscopy showed that the grain sizes within synthetic FeS2 particles were significantly smaller than those within natural FeS2 particles. The superior rate capability of Li/synthetic FeS2 cells was attributed primarily to the smaller grain sizes within synthetic FeS2 particles in comparison to the natural FeS2 sample.
Spinel LiNi0.5Mn1.5O4 materials are synthesized by one-step precipitation method. Ammonium carbonate is used as the precipitating agent to obtain a more precise feed ratio without recourse to traditional washing. After annealing at high temperature, the spherical particles become angular and show high levels of crystallinity. The synthesized samples are evaluated using powder X-ray diffraction, scanning electron microscopy, and electrochemical testing. The samples synthesized with different metal ion concentrations yield different morphologies and rate performances. The sample synthesized with 0.2molL−1 gives the most uniform particle distribution and the best electrochemical performance. The specific discharge capacity values of the sample at 10 and 15C are as high as 109.5 and 88.7mAhg−1, respectively. After the high-rate cycling, its discharge capacity at 0.2C can be reverted to 97.67% of its initial capacity.
The cycle performance of spinel LiMn2O4 at 25 and 55°C is improved by LaF3 modification via a chemical deposition method. The physical and electrochemical performances of pristine and LaF3-coated LiMn2O4 cathode materials are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical measurements. The coated LiMn2O4 with 2.92wt% LaF3 (LaF3-3-LMO) displays capacity retentions of 90.1% and 84.2% at 25 and 55°C, respectively, after 100 cycles, much higher than those of pristine LiMn2O4, 72.7% and 54.8%. The concentration of manganese dissolved from LaF3-3-LMO in electrolyte is much lower than that from pristine LiMn2O4. The analysis of AC impedance indicates that the charge transfer resistance (R ct) and the increase of R ct for LaF3-3-LMO during cycling are much lower than those for pristine LiMn2O4. The significantly improved electrochemical performance of the LaF3-coated LiMn2O4 can be attributed to the reduction of manganese dissolution in electrolyte and charge transfer resistance with the help of LaF3 coating.
The piezoelectric effect in poly(vinylidene fluoride), PVDF, was discovered over four decades ago and since then, significant work has been carried out aiming at the production of high β-phase fibres and their integration into fabric structures for energy harvesting. However, little work has been done in the area of production of “true piezoelectric fabric structures” based on flexible polymeric materials such as PVDF. In this work, we demonstrate “3D spacer” technology based all-fibre piezoelectric fabrics as power generators and energy harvesters. The knitted single-structure piezoelectric generator consists of high β-phase (∼80%) piezoelectric PVDF monofilaments as the spacer yarn interconnected between silver (Ag) coated polyamide multifilament yarn layers acting as the top and bottom electrodes. The novel and unique textile structure provides an output power density in the range of 1.10–5.10 μW cm−2 at applied impact pressures in the range of 0.02–0.10 MPa, thus providing significantly higher power outputs and efficiencies over the existing 2D woven and nonwoven piezoelectric structures. The high energy efficiency, mechanical durability and comfort of the soft, flexible and all-fibre based power generator are highly attractive for a variety of potential applications such as wearable electronic systems and energy harvesters charged from the ambient environment or by human movement.
Social cognition is an important outcome in schizophrenia research. Unfortunately, there has been a lack of consensus regarding which measures of social cognition best capture this domain of functioning. The Social Cognition Psychometric Evaluation (SCOPE) study was developed to address the need for a battery of measures that have sound psychometric properties and can be implemented in clinical trials for individuals with chronic schizophrenia. The current study expands upon the SCOPE study by examining the psychometric properties of the eight candidate measures administered to individuals early in the course of psychosis. Thirty-eight stable outpatients with first episode psychosis and thirty-nine healthy controls completed the battery at baseline and one-month follow-up assessments. The SCOPE battery was evaluated on a collection of psychometric properties, including: (1) Reliability – including test-retest and internal consistency, (2) Between group differences, (3) Utility as a repeated measure, (4) Relationship to social and occupational functioning, (5) Incremental validity – variance in functioning beyond neurocognition, and (6) Feasibility – including practicality of administration and tolerability. Social cognition accounted for substantially more variance in functional outcome than neurocognition. Only one measure, the Hinting task, displayed adequate psychometric properties to be recommended for use in clinical research with first episode psychosis. The remaining candidate measures would require modifications before implementation or cannot be recommended for use in clinical research with first episode psychosis.
The behavioural phenotype of velocardiofacial syndrome (VCFS), one of the most common human multiple anomaly syndromes, includes developmental disabilities, frequently including intellectual disability (ID) and high risk of diagnosis of psychotic disorders including schizophrenia. VCFS may offer a model of the relationship between ID and risk of major mental health difficulties. This paper reviews literature on the cognitive phenotype and its relationship with a polymorphism of the gene coding for catechol O-methyltransferase (COMT), a gene haploinsufficient in VCFS which modulates prefrontal dopamine levels. Principal features of the variable cognitive phenotype of VCFS in young people are ID, superiority of verbal over performance I.Q. and verbal over visuospatial memory, and difficulties with number and object magnitude comparisons, time perception and memory for serial order, and orienting of attention. Despite some improvements with age, problems with higher order attentional tasks involving planning persist, possibly modulated by COMT activity levels. Candidate cognitive endophenotypes include problems with retrieval of contextual information from memory and in executive control and focussing of attention. Longitudinal research using common core batteries of psychometric assessments, and experimental measures of cognitive function capable of direct translation for use with animal models, will further advance understanding of the developmental dynamics of VCFS.
A common approach to reliable load-following is to “slave” fuel cell response to the reactants supply subsystem (e.g. fuel processor). A change-in-power demand may be time-sensitive, however, and slaving the fuel cell response to that of the slower balance-of-plant components may not be practical. A model has been constructed to simulate the unrestrained load-following characteristics of a commercial-grade fuel cell. Analyses have shown that initial conditions exist which facilitate timely responses to increases in load demand, among them lower fuel utilization, larger operating voltage and optimized cell potential reduction.
Recently several cases of observations of unipolar magnetic field pulses associated with earthquakes at different points (California, Italy, Peru) have been recorded. The paper attempts to model unipolar magnetic field pulses based on one mechanism that should be omnipresent for all measurement points, namely, the magnetic field diffusion through a conductive medium. The structure of magnetic fields supported by electric current sources is thoroughly modelled. The source of electric current is considered as an elongated volume of finite cross-section being immersed in a conductive medium. To model the unipolarity feature of the observed pulses prior to and at the earthquake main shock, the electric current of the source is of impulse form. Special attention is paid to the differences in the pulse structure (as amplitude envelope and the pulse width) that are measured by various magnetometers (fluxgate or search-coil). An analysis and comparison with recorded magnetic field pulse characteristics reveal that the observed unipolar pulses may have a common genesis, an electric current source within a conductive medium such as the earth crust.
The revolutionary work of John Goodenough, M. Stanley Whittingham and Akira Yoshino has finally been awarded the Nobel Prize in Chemistry. Scientific discovery and engineering brilliance continue to shape battery technology.
Prosthetists, therapists, and physicians involved with the care of children with limb deficiencies have developed management strategies that have stood up well over the years. These strategies may be challenged and overhauled as new materials, technology, and techniques are introduced and evaluated.