batterydata/paper-abstracts huggingface dataset:
Nickel sulfide-reduced graphene oxide (RGO) composite powders with spherical shapes are prepared by a one-pot spray pyrolysis process. The optimum mole ratio of nickel nitrate and thiourea to obtain nickel sulfide–RGO composite powders with high initial capacities and good cycling performance is 1:8. The bare nickel sulfide and nickel sulfide–RGO composite powders prepared directly by spray pyrolysis have mixed crystal structures of hexagonal α-NiS and cubic Ni3S4 phases. The bare nickel sulfide powders are prepared from the spray solution without graphene oxide sheets. The nickel sulfide–RGO composite powders have sharp mesopores approximately 3.5nm in size. The discharge capacities of the nickel sulfide–RGO composite powders for the 1st and 200th cycles at a current density of 1000mAg−1 are 1046 and 614mAhg−1, respectively, and the corresponding capacity retention measured from the second cycle is 89%. However, the discharge capacities of the bare nickel sulfide powders for the 1st and 200th cycles at a current density of 1000mAg−1 are 832 and 16mAhg−1, respectively. The electrochemical impedance spectroscopy (EIS) measurements reveal the high structural stability of the nickel sulfide–RGO composite powders during cycling.
Lithium-sulfur (Li-S) batteries are considered as an attractive electrochemical energy storage system due to the high theoretical capacity of sulfur (1,675 mA h g−1). However, high-loading sulfur cathodes would need to be employed for the Li-S cells to be practical, but the resulting poor cell cyclability and severe electrode degradation hamper their development. Here, we present a hierarchical sulfur cathode as a testing platform for understanding the high-loading capability of Li-S batteries. The hierarchical cathode presents good electrochemical utilization of above 70%, stable cyclability for 500–1,000 cycles, and high sulfur loadings of 4.2–10.0 mg cm−2. The exploration of the activation and the polysulfide-retention processes of the high-loading cathodes illustrates that the electrochemical stability mainly results from the stabilization of dissolved polysulfides within the cathode region as the electrochemically active catholyte. Therefore, the utilization of stabilized polysulfide migration might be a meaningful opportunity for designing high-loading cathodes and further improving their electrochemical stability and long-term cyclability.
We measured an Al K-edge x-ray absorption near edge structure (XANES) spectrum of Al doped NiO for anode materials of lithium ion batteries. We found that the spectrum of the Al doped NiO is similar to that of γ -Al2O3. Calculated site-specific XANES spectra strongly correspond to the coordination nature around the absorbing Al ion, indicating aggregation of cation vacancies surrounded by Al ions in the Al doped NiO. These finding could be useful to understand how Li ions migrate in the anode.
Modeling and optimization of a hybrid power system comprising several different power sources provides a tool to size the individual power system components and to optimize the power system control variables. The hybrid power system is required to meet the demanding requirements of long duration mission of unmanned surface vehicles (USVs). These demands for power may be met by a combination of renewable energy resources, conventional fossil-fueled energy sources and energy storage options. The hybrid power system being considered here comprises a solar array, an ocean wave energy converter, a fuel cell system, a diesel generator and a lithium ion battery pack. The approach gives high priority to natural energy sources, i.e. solar and wave energy converter within the discrete time domain followed by minimization of a cost/energy ratio associated with the storage based energy elements, i.e., battery pack, fuel cell system (H2 storage) and diesel generator (fuel storage). The results show that optimization has been achieved with 19.6% contribution by solar power during daylight hours and 5.53% contribution of the wave energy harvester to meet the load demands. The battery bank contributes 39.7% which is 4.4% above the fuel cell contribution. The diesel generator does not contribute during the stealth mode of operation of the USV mission. The average percentage energy contribution from each source confirmed the priorities based on minimization of cost/energy ratio of hybrid power elements. However, in the first case study the optimized result shows a constraint violation when fuel cell performs slightly higher than the battery. Later, in the second case study, it is corrected by increasing the size of the battery bank.
In humans and nonhuman primates, the structure and function of frontal cortical regions of the brain are not completely developed until early adulthood. How this cortical development affects cognitive function continues to be elucidated. To that end, this experiment tested the ability of juvenile and adult rhesus monkeys to perform a cognitive task that is dependent upon intact frontal cortical function for optimal performance. Twenty-four juvenile (mean age 2.3 years) and 16 adult (mean age 10.3 years) rhesus monkeys were tested on the Cambridge Neuropsychological Test Automated Battery intradimensional/extradimensional set-shifting (ID/ED) task. Performance on the ID/ED task has been shown to be dependent upon frontal cortical function in both humans and nonhuman primates. Compared with adults, juveniles were impaired on the reversal of simple discrimination, intradimensional shift, reversal of intradimensional shift, and the extradimensional shift stages of the task. These results indicate juveniles committed more perseverative errors and more errors on the set-formation and set-shifting components of the ID/ED task. The developmental stage of the juvenile monkeys corresponds to roughly 5 to 6-year-old children, and these results are consistent with performance of human children and adults on similar ID/ED tests and on several other tests of attentional set-shifting or attentional flexibility. Furthermore, these results are consistent with the ongoing development of frontal cortical structures relating to ongoing cognitive development in nonhuman primates.
NiCo2O4/NiO nanocomposite is successfully synthesized by rapid microwave assisted reflux method at various reaction times. XRD analysis is performed to reveal the crystalline nature and the compound formation. Further, the chemical environment of the surface composition of NiCo2O4/NiO is identified by X-ray Photoelectron spectroscopy. The morphological analysis (FESEM and TEM) of the composite showed that the formation of bundle like irregular large aggregates, which consists of nearly spherical particles. The maximum specific capacitance of 1924Fg−1 at 1mVs−1 in 1M KOH electrolyte with an excellent energy density of 75WhKg−1 at a power density of 103Wkg−1 is revealed for the NiCo2O4/NiO electrode. An asymmetric supercapacitor (ASC) is constructed using optimized NiCo2O4/NiO as positive and synthesized Fe2O3 as negative electrodes. This novel NiCo2O4/NiOǁFe2O3 architecture provides superior capacitive performance with a specific capacitance of 417Fg−1 at 1mVs−1. Subsequently the charge-discharge analysis exhibits the specific capacitance of 79Fg−1 at 1mAcm−2. The fabricated asymmetric supercapacitor (ASC) delivers an energy density of 19Whkg−1 at 157Wkg−1. Moreover, it provides an excellent cycle stability of about 97% capacitance retention over 5000 cycles.
This paper describes two patients, O.I. and B.Y., with a confabulatory syndrome. O.I. was diagnosed with probable fronto-temporal dementia, whereas B.Y. met the criteria for probable Alzheimer's disease. O.I., but not B.Y., was impaired on tests of frontal/executive functions, and performed better than B.Y. on clinical tests of memory. Both patients confabulated in episodic/autobiographical memory tasks and in personal future planning tasks. B.Y. confabulated also in a semantic memory task. It is argued that the pattern of confabulation and the cognitive profile shown by the two patients is explained better by the hypothesis proposed by Dalla Barba and co-workers (Dalla Barba et al., 1997b) than by current theories of confabulation.
Given the negative influence of motor difficulties on people's quality of life their early identification seems to be crucial and consequently the information provided by a sound assessment tool is of great importance. The aim of this study was to examine the suitability of the MOT 4–6 (Zimmer & Volkamer, 1987) for use with preschoolers in Greece. Seven hundred and seventy-eight Greek children aged 48–71 months participated in the study. The two-way ANOVA used on total MOT performance revealed significant differences among the age groups formed in preschool age within Greeks, while boys’ and girls’ scores were quite similar. From the comparisons of Greeks’ scores with the German standardization sample's ones, statistically significant differences were found in two age groups. However according to the Cohen's d effect size they were not of great importance. The distribution of Greeks’ scores according to the test cut-offs, revealed that the MOT can differentiate all levels of performance, although a slight deviation from the distribution of Germans’ scores was noticed. Finally, both the test–retest reliability and internal consistency of the test were found to be excellent. The MOT 4–6 seems to be a valuable motor assessment tool for Greek preschoolers. Regarding its norms, despite the minor differences that were noticed between the motor development of Greek and German preschoolers, their adjustment was thought to be unnecessary. Instead of lowering the norms, efforts for preventing the motor performance decline should be enhanced.
Motion contrast thresholds for 0.4cycle/degree drifting Gabor stimuli were assessed at 15° eccentricity in the right and left visual fields for 16 younger drivers (ages 24–42), and 15 older drivers (ages 65–84), using a temporal two-alternative forced choice staircase procedure. Two self-report questionnaires that assess failures of attention while driving—the Driver Perception Questionnaire (DPQ5), and an abridged Aging Driver Questionnaire (ADQ15)—were administered. The three UFOV® subtests of attention and processing speed were also administered. Mean peripheral motion contrast threshold (PMCT) of older drivers was significantly higher than that of younger drivers. When controlling for age, PMCT thresholds correlated significantly with both DPQ5 and ADQ15 while the UFOV® subtests were found not to correlate with PMCT results. The potential value of the PMCT as an assessment of drivers’ hazard detection capacity is discussed.
Cobalt nanofibers @ Ni3S2 nanosheets (Co@Ni3S2) composites with high surface area (241.67 m2/g) were successfully synthesized via a chemical conversion route. The special nanostructure afforded sufficient space for the volume change, ensured efficient electrolyte penetration, increased contact area between electrolyte and active material during discharge–charge process. Moreover, the existence of the cobalt nanofibers with high conductivity provided a possibility for the rapid transportation of the electrons and lithium ions. The composite electrodes presented a reversible discharge capacity of 531 mAh/g with a good cyclic stability. This research perhaps inspired the designing of high performance electrode materials with a novel structure for high performance energy storage devices.
LiNi0.5Mn1.5O4 spinels coated with various amounts of fumed silica have been synthesized and investigated as cathode materials for high-voltage lithium-ion batteries at the elevated temperature (55°C). The morphology and structure of the coated LiNi0.5Mn1.5O4 samples were characterized by XRD, TEM and EDX. It was found that the surfaces of the coated LiNi0.5Mn1.5O4 samples are covered with a porous, amorphous, nanostructured SiO2 layer. The results of electrochemical experiments showed that the SiO2-coated LiNi0.5Mn1.5O4 samples display obviously improved capacity retention rate, and the improvement effect enhances with the increase of SiO2 content. The XPS results revealed that the surfaces of the SiO2-coated LiNi0.5Mn1.5O4 cathode materials have relatively low content of LiF, and this is mainly responsible for their improved electrochemical cycling stability.
Graphite composite electrodes mixed with silicon are proposed as next generation anode material for high energy and high power applications. In order to overcome drawbacks caused by volume changes of silicon particles during electrochemical cycling and to maintain high specific capacities at enhanced C-rates, free-standing structures are generated on silicon/graphite electrodes by applying ultrafast laser ablation. Electrochemical properties are systematically investigated by means of galvanostatic measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. Cells with structured electrodes exhibit improved battery performances and lithium-ion transport kinetics in comparison to cells with unstructured electrodes. Furthermore, the cells with structured electrodes exhibit a lower impedance at fully lithiated state. After cycling, post-mortem analysis is performed revealing that the mechanical stress within the electrodes and current collector can be significantly reduced due to laser generated free-standing structures.
Ultrathin Co3O4 nanosheets with a mesoporous structure and a large surface area are hydrothermally grown on a three dimensional nickel foam. The ultrathin mesoporous Co3O4 nanosheets are grown on Ni foam with robust adhesion, which endows fast ion and electron transport, large electroactive surface area, and excellent structural stability. Such unique nanoarchitecture exhibits remarkable electrochemical performance with high capacitance and desirable cycle life. When evaluate as an electrode material for supercapacitors, the Co3O4 nanosheets electrode is able to deliver high specific capacitance of 2194Fg−1 at a current density of 1Ag−1 in 1M KOH aqueous solution. The electrode also exhibits excellent cycling stability by retaining 93.1% of the maximum capacitance after 5000 charge-discharge cycles. The fabrication strategy presented here is facile, cost-effective, and can offer a way for energy storage device applications.
A device based on an electrochemical transfer junction (constituted by M x Mo6S8 or M x Mo6Se8) placed between two tanks allows the transfer of cations by application of current density controlled between electrodes placed in tanks. The transfer protocol was tested on different mixed electrolytes containing cations directly engaged in the batteries industry (M2+ =Co2+, Ni2+, Cd2+, Zn2+, Mn2+, Cu2+). Good performances of the process are provided until 1.6mAcm−2. The electrolysis through an electrochemical transfer junction made of Chevrel phases represents a suitable method for the selective extraction of cations with appreciable selectivity rates with an appropriate choice of the host lattice (sulfide or selenide). Remarkable separations between Co/Ni, Zn/Mn with Mo6S8 and Cd/Zn, Cd/Ni, Cd/Co and Zn/Ni, with Mo6Se8 were observed.
A think-aloud method was used to examine the content of information available to working memory during narrative comprehension in a CHI population. Twenty severe CHI participants (>1 year post-injury) and 20 controls talked aloud after they read each sentence of story narratives. Trabasso and Magliano’s (1996a) verbal protocol analysis was then used to code for the production of inferential and non-inferential clauses and the memory operations that supported inferential clause production. We found that CHI and control groups produced a comparable number of clauses, that inferences dominated narrative comprehension, and that both groups produced more explanatory inferences than predictive or associative inferences. Despite these qualitative similarities, the CHI group demonstrated poorer comprehension, generated proportionately fewer inferences, relied less on retrieval as a memory source for explanatory inferences, and produced more non-inferential clauses and associative inferences.
Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors.
We report a simple strategy to prepare Li4Ti5O12/Cu nanoparticles as an anode material for high rate lithium ion batteries. The copper nanoparticles are highly dispersed on the surface of Li4Ti5O12 through hydrothermal process and a short post -annealing. X-ray diffraction, Field-emission scanning electron microscopy and transmission electron microscopy are performed to characterize their structures and morphologies. The cyclic voltammetry, galvanostatic charge/discharge and alternate current impedance are used to evaluate their electric performance. Compared to pure Li4Ti5O12, the Li4Ti5O12/Cu composites has high rate capability, capacity retention and excellent cycling performance. The results show that copper nanoparticles enhance the electric conductivity of Li4Ti5O12/Cu, and prevent agglomeration.
Developing nanostructure hybrid electrode with multiple electroactive sites offer an encouraging path to build high-performance supercapacitors (SCs). Herein, we report fluorinated graphene (FG) -supported Nickel-Cobalt-Iron nitride nanoparticles on nickel foam (NCF-N@FG/NF), as a hybrid SCs electrode. They were fabricated via one-step nitrogenization treatment in NH3 atmosphere at different temperatures 300–500 °C of the corresponding Ni-Co-Fe-tri-hydroxide/FG precursors. The optimal NCF-N@FG/NF hybrid, with Fe:Co:Ni 3:1:1(denoted as NCF-N@FG/NF-3/500 °C) yielded specific capacitance (capacity) of 2110 F/g (293.1 mAh/g) at 1 A/g, rate capability of 87.2% at 20 A/g, and capacitance retention of 97.6% after 5000 cycles. Asymmetric supercapacitor (ASC) device was set up using NCF-N@FG/NF-3/500 °C hybrid as the cathode and activated carbon supported NF (AC@NF) as the anode (denoted as NCF-N@FG/NF-3/500 °C/CKK membrane/AC@NF). The device exhibited a stable potential window of 1.5 V and excellent cycling stability with only 11.5% decrease of capacitance after 10 000 cycles. Also, it achieved an energy density of 56.3 Wh/kg at 0.5 A/g with a power density of 374.6 W/kg. The device retained an energy density of 39.5 Wh/kg at 10 A/g with a power density of 7484.2 W/kg. This work constitutes the first demonstration of using FG supported tri-metallic nitride nanoparticles as high energy Cathode, which could potentially enhance the energy storage performance of ASC devices.
To address the large structural and volume changes of commercial WO3 during charge/discharge, which make this material unsuitable for use in Li-ion batteries (LIBs), we herein prepared oxygen deficient WO3-x nanosheets on a large scale by thermal treatment of ammonium paratungstate in a reducing atmosphere followed by sonication and freeze-drying. The above nanosheets were employed as LIB anode materials and exhibited a specific capacity and cycling stability significantly exceeding those of oxygen-deficient WO3-x nanoparticles and commercial WO3. In addition, we investigated the effect of nanosheet loading on electrode performance, demonstrating that the best results (Li storage capacity of ∼628 mAh g−1 after 100 cycles at 100 mA g−1) were obtained at a nanosheet content of 20 wt%. This excellent performance was ascribe to the good exposure of defects caused by the comparatively small size of WO3-x nanosheets, which resulted in an increased number of sites and diffusion paths available for Li-ion storage and transfer. The novel electrode-optimized strategy may be extended to the fabrication of other electrodes that use nanomaterials as active substances due to its superior comprehensive performance and low cost.
Energy storage systems are spreading both in stationary and transport applications. Among innovative storage devices, lithium ion capacitors (LiCs) are very interesting. They combine the advantages of both traditional electric double layer capacitors (EDLCs) and lithium ion batteries (LiBs). The behavior of this device is much more similar to ELDCs than to batteries. For this reason, several models developed for traditional ELDCs were extended to LiCs. Anyway, at low temperatures LiCs behavior is quite different from ELDCs and it is more similar to a LiB. Consequently, EDLC models works fine at room temperature but give worse results at low temperatures. This paper proposes a new electric model that, overcoming this issue, is a valid solution in a wide temperature range. Based on only five parameters, depending on polarization voltage and temperature, the proposed model is very simple to be implemented. Its accuracy is verified through experimental tests. From the reported results, it is also shown that, at very low temperatures, the dependence of the resistance from the current has to be taken into account.