batterydata/paper-abstracts huggingface dataset:
Children with Developmental Coordination Disorder (DCD) experience considerable difficulties coordinating and controlling their body movements during functional motor tasks. Thus, it is not surprising that children with DCD do not perform well on tests of physical fitness. The aim of this study was to determine whether deficits in motor coordination influence the ability of children with DCD to perform adequately on physical fitness tests. A case–control study design was used to compare the performance of children with DCD (n =70, 36 boys, mean age=8y 1mo) and Typically Developing (TD) children (n =70, 35 boys, mean age=7y 9mo) on measures of isometric strength (hand-held dynamometry), functional strength, i.e. explosive power and muscular endurance (Functional Strength Measurement), aerobic capacity (20m Shuttle Run Test) and anaerobic muscle capacity, i.e. muscle power (Muscle Power Sprint Test). Results show that children with DCD were able to generate similar isometric forces compared to TD children in isometric break tests, but were significantly weaker in three-point grip strength. Performance on functional strength items requiring more isolated explosive movement of the upper extremities, showed no significant difference between groups while items requiring muscle endurance (repetitions in 30s) and items requiring whole body explosive movement were all significantly different. Aerobic capacity was lower for children with DCD whereas anaerobic performance during the sprint test was not. Our findings suggest that poor physical fitness performance in children with DCD may be partly due to poor timing and coordination of repetitive movements.
Lithium sulfur (Li–S) batteries are one of the most promising next generation battery chemistries with potential to achieve 500–600 W h kg−1 in the next few years. Yet understanding the underlying mechanisms of operation remains a major obstacle to their continued improvement. From a review of a range of analytical studies and physical models, it is clear that experimental understanding is well ahead of state-of-the-art models. Yet this understanding is still hindered by the limitations of available techniques and the implications of experiment and cell design on the mechanism. The mechanisms at the core of physical models for Li–S cells are overly simplistic compared to the latest thinking based upon experimental results, but creating more complicated models will be difficult, due to the lack of and inability to easily measure the necessary parameters. Despite this, there are significant opportunities to improve models with the latest experimentally derived mechanisms. Such models can inform materials research and lead to improved high fidelity models for controls and application engineers.
The influence of several processing conditions on the phase formation and electrochemical performance of LiNi0.5Mn0.5O2 powders, obtained by freeze drying method, is studied. Thermal processing in pellets at maximum heating rate promotes better crystallographic ordering of hexagonal LiNi0.5Mn0.5O2 and maximum capacity values irrespectively of chemical composition of the precursor. Instead, intense mechanical processing of precursors exerts considerable negative effect on the electrochemical performance. Cathode materials containing superstoichiometric amount of lithium (Li1.3Mn0.5Ni0.5O2+δ) demonstrate reversible capacity values up to 190mAh/g between 2.5 and 4.6V.
The electrochemical reactivity of the ball-milled ilmenite FeTiO3 and ilmenite nanoflowers with lithium has been investigated. The electrode assembled with the ilmenite nanoflowers delivers better electrochemical performance than that of the milled material during charging and discharging in the potential range of 0.01 and 3V vs. Li/Li+. The ilmenite nanoflowers demonstrate the capacity of ca. 650mAhg−1 during the first discharge, and a reversible capacity of approximately 200mAhg−1 in the course of the first 50 cycles. The possible reaction mechanism between ilmenite and lithium was studied using cyclic voltammetry and transmission electron microscopy. The first discharge involves the formation of an irreversible phase, which is either LiTiO2 or LiFeO2. Subsequently, the extraction–insertion of lithium happens in a reversible manner. It was also observed that the lithium storage might be significantly improved if the electrode was prepared in the form of a nanocomposite of FeTiO3 with carbon.
Super-hydrophilic conducting polyaniline was prepared by surface modification of polyaniline using tetraethyl orthosilicate in water/ethanol solution, whereas its conductivity was 4.16Scm−1 at 25°C. And its electrochemical capacitance performances as an electrode material were evaluated by the cyclic voltammetry and galvanostatic charge/discharge test in 0.1M H2SO4 aqueous solution. Its initial specific capacitance was 500Fg−1 at a constant current density of 1.5Ag−1, and the capacitance still reached about 400Fg−1 after 5000 consecutive cycles. Moreover, its capacitance retention ratio was circa 70% with the growth of current densities from 1.5 to 20Ag−1, indicating excellent rate capability. It would be a promising electrode material for aqueous redox supercapacitors.
To explore the benefit finding (BF) relationship between colorectal cancer (CRC) survivors and their spousal caregivers, and to discover the dyadic impact of BF on quality of life (QOL) in CRC survivor and spousal caregiver couples.
This study adopts high-concentration ether electrolytes to improve high-rate capability, cycling stability, and Coulombic efficiency (CE) for lithium ion batteries with lithium anode. A series of ether-based electrolytes including lithium bis(fluorosulfonyl)imide (LiFSI)-glyme/ethylene carbonate (EC), LiFSI-glyme/EC, LiFSI-diglyme/EC, LiFSI-triglyme/EC, LiFSI-tetraglyme (G4)/EC, and LiFSI-1,3-dioxolane (DOL)/EC, along with commonly used LiPF6-DEC/EC were prepared to delineate the influences of concentration, chain length, molecular structure (linear or ring ether), and EC additive on the electrochemical performance of Li anodes. An optimum composition for ether-based electrolyte was determined resulting in significant improvement in anti-flammability as well as CE at both low and high rates. At ultra-high current density operation (e.g. 6 mA cm−2), the CE was 95.5 and 97.1% with 3 M LiFSI-G4/EC and 3 M LiFSI-DOL/EC, respectively. Using 1 M LiPF6 carbonate-based electrolyte tend to grow a needle-like dendritic structure when depositing lithium metal on Cu foils, whereas high-concentration ether electrolyte promotes a knot-like and rounded Li metal microstructure. High concentration EC-based electrolytes, are capable of facilitating Li+ almost in tandem with solvent molecules, thereby reducing the number of free molecules, reducing the chance of side reaction with Li metal, and subsequently inhibiting the formation of dendritic Li structures.
Objective To investigate the probable cortical excitability changes in DMD by electrophysiological means. Methods Sixteen cases with DMD, 10 age-matched control children (CC) and 10 healthy adult volunteers (AC) were studied with a transcranial magnetic stimulation (TMS) test battery composed of central conduction time, cortical silent period and paired TMS paradigm. Results There were no significant differences between DMD and CC groups except for lower amplitude motor responses in DMD cases. These two groups showed a similar pattern of excitability with less short interval intracortical inhibitions and shorter silent period durations as compared to the AC subjects. Conclusions The electrophysiological tests performed in our DMD patients did not reveal abnormalities caused particularly by the disorder. Significance TMS excitability studies performed in DMD boys may not provide findings other than those related to the developmental age.
To investigate the crystal structure and electrochemical performance of samples synthesized under different microwave solid-state synthesis condition, a series of Li3V2(PO4)3 samples has been synthesized at five different temperatures for 3–5min and at 750°C for various time. The as-synthesized Li3V2(PO4)3 samples are characterized and studied by ICP-AES analysis, X-ray diffraction (XRD), Rietveld analysis, scanning and transmission electron microcopy (SEM and TEM). At relatively lower temperature (650°C) and very short reaction time (3min), pure phase of Li3V2(PO4)3 could be synthesized in microwave irradiation field. The crystal structure and Li atomic fractional coordinate present a significant deviation upon the change of microwave irradiation temperature and time. Relatively, the diffusion ability of lithium cations and the electrochemical performance are affected. Under the proper reaction temperature and time, the carbon-free samples MW750C5m and MW850C3m show the best specific discharge capacity 126.4 and 132mAhg−1 at the voltage range of 3.0–4.3V, near the reversible cycling of two lithium ions per Li3V2(PO4)3 formula unit (133mAhg−1). At the voltage range of 3–4.8V, the sample MW750C5m presents the best initial specific charge capacity of 197mAhg−1, equivalent to the reversible cycling of three lithium ions per Li3V2(PO4)3 formula unit (197mAhg−1). The initial discharge capacity, the samples MW750C5m and MW850C3m present high specific discharge capacity 183.4 and 175.7mAhg−1, respectively. The relationship among microwave irradiation condition, crystal structure, lithium atomic fractional coordinates and the electrochemical performance have been discussed in detail.
Nano-metal embedded Li4Ti5O12/C composites (Li4Ti5O12/M/C samples labeled as Li4Ti5O12/Sn/C-L, Li4Ti5O12/Sn/C-H, Li4Ti5O12/Sb/C-L, Li4Ti5O12/Sb/C-H, Li4Ti5O12/Bi/C-L and Li4Ti5O12/Bi/C-H, respectively) as high capacity anode were synthesized by sol-gel and high temperature solid state reaction methods. The physical properties of Li4Ti5O12/M/C were detected by X-ray diffraction (XRD), scanning microscopy (SEM), transmission electron microscopy (TEM) and elemental analysis. All composites were completely coated by a thin carbon layer. Besides the Li4Ti5O12/Bi/C-L, other Li4Ti5O12/M/C samples were composed of spherical-like aggregate particles. Nano-M was embedded between inner Li4Ti5O12 and outer carbon layer. Their electrochemical performances were studied by galvanostatic cycle and cyclic voltammograms (CVs). These analyses show that Li4Ti5O12/Sn/C-L, Li4Ti5O12/Sn/C-H, Li4Ti5O12/Sb/C-H, Li4Ti5O12/Bi/C-H delivered a reversible capacity of 231.9, 308.1, 235.9 and 213.5mAhg−1 at 500th cycle on current density of 200mAg−1, respectively, while Li4Ti5O12/C composite only delivered a capacity of 197.6mAhg−1 at the same conditions. The results demonstrated that metal M can play an important role on high capacity performance of Li4Ti5O12-based anode when it was embedded between inner “zero-strain” Li4Ti5O12 and outer carbon coating layer. Their stable cycle performance owning to the co-effect of Li4Ti5O12 as the structural stabilizer and carbon layer as the volume change buffer for preventing the volume change caused by M during cycling. This work provides an effective way to improve the discharge capacity of Li4Ti5O12-based anodes.
Wrought Mg-Al-Pb-RE strips of different thicknesses are synthesized via extrusion and used as the anodes in Mg-air batteries. We find that, compared to other Mg-Al-Pb-RE samples, the 5 mm-thick strip exhibits greater stability and higher discharge voltage plateaus for long time (10 h). Its anodic efficiency at 10 mA cm−2 reaches 64.1%, which is even higher than pure magnesium and AZ31 magnesium alloy. The outstanding performance of the 5 mm-thick Mg-Al-Pb-RE anode strip is attributed to its unique microstructure favourable for anodic dissolution. Furthermore, the correlations between microstructure features and electrochemical performance for the wrought Mg-Al-Pb-RE strips are also systematically defined.
LiNi0.6Mn0.2Co0.2O2 (C622) is one of the Ni-rich layer-structured cathode materials with a high capacity, but it suffers from a poor cycling stability and rate capability. In this study, Li1.3Al0.3Ti1.7(PO4)3 (LATP), a NASICON-type lithium-conductor, is coated on C622 by a sol–gel process to overcome the shortcomings of C622. We find that a 0.5 wt% coating of LATP on C622 significantly improves the cell performance including the discharge capacity, rate capability, and cycling stability. The pristine and LATP-coated samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). In addition, various electrochemical analyses such as cyclic-voltammetry (CV), galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS) are conducted to determine the reason for the improvement of the cell performance. The cell performance of C622 is enhanced by a coating amount of less than 1.0 wt% and the overall performance degrades with the increase of the coating amount. The electrochemical analyses reveal that a high lithium-ion diffusion coefficient and a low interfacial resistance are the reasons for the improved cell performance; however, our study demonstrates that an excessive coating may degrade the cell performance, thereby acting as a barrier against the movement of lithium ions.
An analytical study of the effect of diffusioosmosis caused by the concentration gradient of hydrogen ions on the isothermal transport of water in a fully hydrated membrane of a polymer electrolyte fuel cell (PEFC) is presented. A capillary tube or slit with a negatively charged wall is chosen to model the nanopores of the membrane. The electric double layer adjacent to the capillary wall may have an arbitrary thickness relative to the capillary radius and its electrostatic potential distribution is determined as the solution of the Poisson–Boltzmann equation. Solving a modified Navier–Stokes equation, the fluid velocity in the axial direction of the capillary induced by the macroscopic electric field and protonic concentration gradient is obtained as a function of the radial position in closed forms. The results for the local and averaged electrokinetic velocities in the capillary show that the effect of diffusioosmosis on the water transport in the membrane of a PEFC can be significant in comparison with that of electroosmosis under low-potential-difference operations.
An electroplated copper/tin (Cu/Sn) anode with a layered structure is described that minimizes the high-voltage irreversible capacity observed in an electroplated Sn anode at a potential over 1V. The high-voltage irreversible capacity is caused by the electrolyte decomposition at the catalytic site of the Sn anode. In the electroplated Cu/Sn anode, the upper Cu layer effectively suppresses the exposure of the newly formed Sn surfaces, resulting in the absence of the high-voltage irreversible capacity. Therefore, the electroplated Cu/Sn anode exhibits a higher cycle performance than the electroplated Sn anode.
Children in elementary school, along with college adults, were tested on a battery of basic mathematical tasks, including digit naming, number comparison, dot enumeration, and simple addition or subtraction. Beyond cataloguing performance to these standard tasks in Grades 1 to 5, we also examined relationships among the tasks, including previously reported results on a number line estimation task. Accuracy and latency improved across grades for all tasks, and classic interaction patterns were found, for example, a speed-up of subitizing and counting, increasingly shallow slopes in number comparison, and progressive speeding of responses especially to larger addition and subtraction problems. Surprisingly, digit naming was faster than subitizing at all ages, arguing against a pre-attentive processing explanation for subitizing. Estimation accuracy and speed were strong predictors of children’s addition and subtraction performance. Children who gave exponential responses on the number line estimation task were slower at counting in the dot enumeration task and had longer latencies on addition and subtraction problems. The results provided further support for the importance of estimation as an indicator of children’s current and future mathematical expertise.
A comprehensive matrix of composite poly(ethyleneoxide) (PEO)-based solid-state electrolytes was developed in order to systematically study a number of variables and their impact upon the electrochemical properties of the resulting materials. The different parameters studied in the fabrication of these materials include: (i) the lithium electrolyte salt type, (ii) the ether oxygen to lithium ratio, (iii) the molecular weight of PEO, (iv) the type of ceramic additive used, either aluminum oxide (Al2O3), silicon oxide (SiO2), or titanium oxide (TiO2), (v) the particle size of the additives used, and (vi) the concentration of additive (wt.%). The standard lithium salt used for the preparation of these electrolytes was lithium trifluoromethanesulfonate (lithium triflate or LiSO3CF3), which served as the baseline electrolyte salt. Other lithium salts investigated include: lithium perchlorate (LiClO4) and lithium bis-trifluoromethanesulfonimide (LiN(SO2CF3)2). Conductivity measurements were performed for each electrolyte membrane over a wide temperature range (23–100°C). In addition, cyclic voltammetry measurements were performed on selected PEO membranes as a function of temperature to determine the impact of various parameters upon the electrochemical stability. It was observed that the parameter that displayed the most significant effect upon the PEO-base polymer conductivity was the lithium salt type employed. The lithium triflate salt-containing PEO polymers demonstrated the best mechanical properties before and after heat treatment. Ceramic fillers also appear to enhance the mechanical properties of PEO polymer electrolytes at temperatures above the melting point of PEO (60–70°C). In addition to investigating the electrochemical characteristics of the composite membrane, solid state 7Li NMR characterization was performed to study ionic mobility by measuring spectral line widths and lithium self-diffusion coefficients. It was determined that ceramic nanoparticle additives can enhance the Li+ diffusivity without a corresponding increase in polymer segmental mobility.
Li2Na2Ti6O14 and its Ti-site substitution Li2Na2Ti5.9M0.1O14 (M = Al, Zr, V) are prepared by a solid-state reaction method and used as anode materials for lithium-ion batteries. It is found that metal doping can effectively enhance the electronic conductivity and ionic diffusion coefficient of Li2Na2Ti6O14. Especially for Li2Na2Ti5.9Al0.1O14, it reveals the highest electronic conductivity (1.02 × 10−9 S cm−1) and lithium ion diffusion coefficient (8.38 × 10−15 cm2 s−1) among all the samples. As a result, Li2Na2Ti5.9Al0.1O14 reveals the best electrochemical performance. It can deliver a charge specific capacity of 270.3 mAh g−1 at 50 mA g−1. Even cycled at 1000 mA g−1, it still can present a charge capacity of 180.7 mAh g−1. All these enhanced lithium storage capabilities of Li2Na2Ti5.9Al0.1O14 should be attributed to the increased electronic/ionic conductivities and the decreased charge transfer resistance induced by Al doping. Besides, in-situ X-ray diffraction observation also confirms that the structural change of Li2Na2Ti5.9Al0.1O14 is highly reversible process for lithium storage.
Tailoring the structure of Ni-rich ternary layered cathode is considered as an effective way to solve its poor cycling and rate capability. Herein, a special structure of Ni0.6Co0.2Mn0.2(OH)2 precursor, in which strips composed of lamellar primary particles are vertically inserted, is rationally designed through feasible industrialized co-precipitation process. Particularly, precursor possesses a loose interior and dense exterior structure by observation of cross section. After sintering, LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode shows monodispersed microspheres whose external surface is tightly wrapped rod-like primary particles. Moreover, NCM622 microspheres inherits the properties of Ni0.6Co0.2Mn0.2(OH)2 precursor, displaying hollow structure and aligned primary particles along the radial direction. NCM622 cathode shows optimal electrochemical properties in the voltage window of 2.8–4.4 V. It displays a revisable capacity of 142.4 mAh g−1 (79.3% for capacity retention ratio) after 300 cycles under current density of 1 C. A reversible capacity of 110.3 mAh g−1 can be obtained after 500 cycles even at current density of 3 C, and corresponding capacity decay rate is only 0.068% for each cycle. The tailored cathode has great potential applications in batteries of high-power and long calendar life as well as provides an idea for structural design of high nickel cathode.
Tailoring carbon based negative electrode by grafting electroactive 9,10-phenanthrenequinone molecules on porous carbon drastically improves the performance of a carbon/Ni(OH)2 hybrid electrochemical capacitor. The grafted-quinone moieties add a Faradaic contribution to the double layer capacitance of carbon leading to a significant increase of the charge stored by the full devices. Good cyclability is ensured due to the strong bond between 9,10-phenanthrenequinone molecules and the carbon surface. More importantly, by increasing the total capacity, the grafting improves the energy density of the full hybrid device while maintaining fast charge/discharge kinetics and thus without affecting the power density.
A fundamental understanding of the anodic stabilities of electrolytes is important for the development of advanced high-voltage electrolytes. In this study, we calculated and systematically compared the oxidation stabilities of monomeric solvents and anions, and bimolecular solvent–solvent and anion–solvent systems that are considered to be high-voltage electrolyte components, using ab initio calculations. Oxidation stabilities of solvent or anion monomers without considering specific solvation molecules cannot represent experimental oxidation stabilities. The oxidation of electrolytes usually forms neutral or cationic radicals, which immediately undergo further reactions stabilizing the products. Oxidatively driven intermolecular reactions are the main reason for the lower oxidation stabilities of electrolytes compared with those of monomeric compounds. Electrolyte components such as tetramethylene sulfone (TMS), ethyl methyl sulfone (EMS), bis(oxalate)borate (BOB−), and bis(trifluoromethane)sulfonamide (TFSI−) that minimize such intermolecular chemical reactions on oxidation can maintain the oxidation stabilities of monomers. In predictions of the theoretical oxidation stabilities of electrolytes, simple comparisons of highest occupied molecular orbital energies can be misleading, even if microsolvation or bulk clusters are considered. Instead, bimolecular solvent complexes with a salt anion should be at least considered in oxidation calculations. This study provides important information on fundamental and applied aspects of the development of electrolytes.