batterydata/paper-abstracts huggingface dataset:
A series of CoO/reduced graphene oxide (CoO/RGO) composites with different proportions are successfully synthesized via a hydrothermal method. As an additive for the nickel-based alkaline secondary battery cathode, the electrochemical performances of the proposed CoO/RGO composite are systematically investigated on its cyclic stability, rate capability, capacity recovery performance, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), in comparison with commercial CoO. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images show that the CoO nanoparticles are in-situ anchored on the surface of soft and flexible graphene sheets. Electrochemical results indicate that the CoO/RGO composites exhibite the highest performance when the weight ratio of CoO and RGO is 5:5. The optimized CoO/RGO composites as an additive for the nickel electrode not only can substantially reduce the CoO additive but also possess good electrochemical performances, especially for the high-rate capability. The discharge capacity of the nickel electrode with 5wt% of CoO/RGO (5:5) addition deliver a high discharge capacity of 284.3, 264.6,235.4 and 208.6mAhg−1 at 0.2, 1.0, 5.0 and 10.0C, respectively. The capacity recovery rate at 0.2C can reach 98.4%. CV and EIS test indicate that the incorporation of RGO can significantly enhance the reversible property, current density of cathodic peak, proton diffusion and conductivity of the nickel electrode.
The currently high upfront costs of batteries and the low retail electricity prices of households make investments in PV–battery systems not yet economically feasible. However, the experiences/learning curves of renewable generation technologies lead to the assumption that battery prices will rapidly decline with increasing diffusion. Furthermore, projected retail electricity rates are expected to increase with rising electricity demand. This study investigates the returns to residential customers using PV–battery systems under decreasing battery prices in Thailand. The impacts of four additional parameters have been included. The analysis is based mainly on net present values (NPV) and levelized costs of electricity (LCOE). The results show that battery size and its cost, and retail rate design have significant impacts on the returns, whereas buyback incentives for excess electricity have the lowest impact. In addition, to increase the power system flexibility by using PV–battery systems, the Thai government should provide the appropriate financial support, by which the savings incurred by the grid extension investments compensate for the costs.
Environmentally friendly supercapacitors are fabricated using commercial grade aluminum coated paper as a substrate and symmetrical activated carbon electrodes as large area electrodes. Different choline chloride-based eutectic solvents are used as electrolyte. These are inexpensive, environmentally friendly and have a larger operating window compared to that of water electrolytes. As the entire device is printed and the materials used are inexpensive, both small- and large-area power sources can be fabricated to be used in cheap, disposable and recyclable devices. Supercapacitors with different eutectic solvents are measured using cyclic charge–discharge and impedance spectroscopy measurements and compared to one widely used and one “green” imidazolium ionic liquid; EMIM:TFSI and EcoEng 212™, respectively. A mixture of ethylene glycol and choline chloride, Glyceline™, show the highest capacitance and power densities of the electrolytes being tested, including the imidazolium alternatives.
As standard rTMS protocols exhibit after-effects of short duration and show limited efficacy as therapeutic intervention in psychiatric and neurological disorders, novel protocols, e.g. theta burst stimulation (TBS), have been developed for motor cortex stimulation and are promising approaches to enhance the effectiveness of rTMS. However, little is known about the side effect profile of such protocols. Thus, the present study investigates whether TBS is safe in terms of side effects and has effects on cognition and EEG measurements. Within two exploratory placebo-controlled, cross-over studies, 24 healthy volunteers underwent continuous TBS (cTBS), intermittent TBS (iTBS) and sham TBS over the left dorsolateral prefrontal cortex (DLPFC, N=12) or the medial prefrontal cortices (mPFC, N=12) in random order. Side effects, resting EEG, performance in a neuropsychological test battery and mood were recorded. All protocols proved to be safe in terms of seizure generation. The most prominent side effect was the occurrence of vasovagal reactions after TBS. Standardized low resolution brain electromagnetic tomography (sLORETA) showed changes in current source density of different frequency bands in the frontal lobe with simultaneous effects in neuropsychological data. Although TBS protocols of the human prefrontal cortex appear to be rather safe, future studies need to explain the occurrence of vasovagal reactions with TBS. The excitatory and inhibitory mechanisms of TBS reported for the motor cortex are not easily transferable to prefrontal sites. Moreover, TBS seems to exert long lasting effects after iTBS over the left DLPFC.
We report the utilization of three-dimensional graphene hydrogel embedded with Ni foam as a high-surface-area support and one-step electrodeposition of NiCo2O4 nanoflakes on the support for use as supercapacitor electrode, with dramatic improvements in the accessible electrode surface area and loading amount of pseudocapacitive material being achieved. The constructed NiCo2O4/graphene hydrogel/Ni foam ternary composite electrode possesses a hierarchical open-porous structure scaling from macropores to mesopores, which synergistically provides continuous electron path, commodious ion channel and large electrolyte-electrode interface, thus benefiting the improvement of overall energy storage properties of the supercapacitor electrode. Accordingly, the as-prepared electrode exhibits exceptional high capacitance of 3.84 F cm−2 at 2 mA cm−2 and excellent rate capability with 71.6% retention at 50 mA cm−2. Moreover, the assembled asymmetric supercapacitor using NiCo2O4/graphene hydrogel/Ni foam as positive electrode and graphene hydrogel/Ni foam as negative electrode renders a maximum energy density and power density of 65 Wh kg−1 and 18.9 kW kg−1, respectively, and a striking cycling stability with 92% capacitance retention after 5000 charge-discharge cycles. These desirable results suggest a great potential of hierarchical porous NiCo2O4/graphene hydrogel/Ni foam electrode for the high-performance supercapacitor application.
A mille-feuille structure, which comprises both sides of dense layer are sandwiched by porous layers, is one of the promising structures for 3-dimensional (3D) all-solid-state battery. The porous layers should have 3-dimensionally ordered macroporous structure to obtain large contact area between electrolyte and electrode. Li0.35La0.55TiO3 (LLT) solid electrolyte with the mille-feuille structure was fabricated by the suspension filtration method. The dense layer was sintered well, no grain boundary was observed. The porous layers contacted well with dense layer. Thicknesses of dense and porous layers were 30 and 26μm, respectively. To check compatibility of the mille-feuille LLT with all-solid-state Li ion battery, chronopotentiometry of symmetric cell with LiMn2O4/mille-feuille LLT/LiMn2O4 configuration was measured. Charge and discharge currents were clearly observed, indicating that the cell was successfully operated.
Lithium plating in commercial LiNi1/3Mn1/3Co1/3O2/graphite cells at sub-ambient temperatures is studied by neutron diffraction at Stress-Spec, MLZ. Li plating uses part of the active lithium in the cell and competes with the intercalation of lithium into graphite. As a result, the degree of graphite lithiation during and after charge is lower. Comparison of graphite lithiation after a C/5 charging cycle fast enough to expect a considerable amount of Li plating with a much slower C/30 reference cycle reveals a lower degree of graphite lithiation in the first case; neutron diffraction shows less LiC6 and more LiC12 is present. If the cell is subjected to a 20 h rest period after charge, a gradual transformation of remaining LiC12 to LiC6 can be observed, indicating Li diffusion into the graphite. During the rest period after the C/5 charging cycle, the degree of graphite lithiation can be estimated to increase by 17%, indicating at least 17% of the active lithium is plated. Data collected during discharge immediately after C/5 charging give further evidence of the presence and amount of metallic lithium: in this case 19% of discharge capacity originates from the oxidation of metallic lithium. Also, lithium oxidation can be directly related to the high voltage plateau observed during discharge in case of lithium plating.
A sub-atmospheric pressure nickel hydrogen (Ni–H2) battery with metal hydride for hydrogen storage is developed for implantable neuroprosthetic devices. Pressure variations during charge and discharge of the cell are analyzed at different states of charge and are found to follow the desorption curve of the pressure composition isotherm (PCI) of the metal hydride. The measured pressure agreed well with the calculated theoretical pressure based on the PCI and is used to predict the state of charge of the battery. Hydrogen equilibration with the metal hydride during charge/discharge cycling is fast when the pressure is in the range from 8 to 13psia and slower in the range from 6 to 8psia. The time constant for the slower hydrogen equilibration, 1.37h, is similar to the time constant for oxygen recombination and therefore pressure changes due to different mechanisms are difficult to estimate. The self-discharge rate of the cell with metal hydride is two times lower in comparison to the cell with gaseous hydrogen storage alone and is a result of the lower pressure in the cell when the metal hydride is used.
Objective Children's differences in moderate-to-vigorous physical activity levels are not at random. This study investigates the relevance of individual- and school-level characteristics in explaining these differences. Methods In total, 307 children (154 girls) aged 5–10 years, from 19 Portuguese schools, were sampled. Height and weight were measured, and body mass index was calculated. Time spent in moderate-to-vigorous physical activity was measured by accelerometry. Gross motor coordination was assessed with the KörperkoordinationsTest für Kinder battery and socio-economic status was obtained via the school social support system. School characteristics were obtained with an objective school audit. A multilevel analysis was used as implemented in Stata 15. Results Schools explained 18.2% of the total variance in moderate-to-vigorous physical activity, with the remainder being ascribed to children's distinct characteristics. Boys were more active (β =29.59±11.52, p <0.05), and having higher gross motor coordination levels (β =0.11±0.04, p <0.05) was positively associated with daily moderate-to-vigorous physical activity, whereas being older (β =−5.00±1.57, p <0.05) and having higher socio-economic status (β =−7.89±3.12, p <0.05) were negatively related with moderate-to-vigorous physical activity. From the school-level correlates, only playground dimension was significantly associated with moderate-to-vigorous physical activity levels. Children from schools with medium (40m2 to 69m2) and large playground dimensions (≥70m2) were less active than children with smaller playground dimensions (10m2 to 39m2). Conclusions Variation in school children's moderate-to-vigorous physical activity is mostly explained by their individual characteristics; school characteristics also play a role but to a smaller degree. Future intervention programs to change this behavior should be more personalized, emphasizing mostly individual-level characteristics.
Mackinawite films have been deposited on Ti supports from aqueous solutions containing ferrous and thiosulphate ions, using a potentiostatic double pulse technique. Studies on the influence of the electrolyte concentration ratio [S2O3 2−]/[Fe2+] on the film properties were performed. Cyclic voltammetry was used as a diagnostic technique for the electrodeposition process. In situ characterisation of the deposits was performed by anodic stripping analysis. The structure and morphology of the films were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The experimental data provide evidence that Mackinawite deposits have been obtained from the entire electrodeposition baths although its purity is conditioned by the bath composition. Namely, when [S2O3 2−]=[Fe2+], oxidation products such as α-S and γ-FeOOH were detected.
An amorphous, thin film of tin oxide is tested as an anode to replace lithium metal in a thin-film battery. Tin oxide shows irreversible discharge capacity in its initial state, and this gives rise to capacity loss on the first charge–discharge process. Thus, in terms of electrochemical properties, lithium metal is better than tin oxide as an anode for a thin-film battery. In some applications, however, thin-film batteries must withstand high fabrication temperatures (over 250°C to 260°C). Lithium metal film cannot be applied in such conditions due to its low melting point (181°C). Tin oxide is not only able to endure high fabrication temperatures but can also preserve its capacity for a large number of cycles after the initial discharge process. In this study, a thin film of amorphous tin oxide has been prepared by means of a sputtering method. Its suitability as an anode for a thin-film battery is examined. A thin film of LiMn2O4, prepared by a sol–gel method is used for the cathode.
The solution-reaction calorimetric method was used for the determination of the formation enthalpy of the Li22Si5 intermetallic compound and the heat of the reaction of the Li-component with an acetic acid bath. The phase was prepared in a glove box with high purity argon protective atmosphere. The phase was homogenized and then analyzed by means of the X-ray diffraction technique. Also, the topography analysis was performed with the use of a scanning electron microscopy (SEM), whereas the microstructure analysis was performed by means of a transmission electron microscopy (TEM). The phase analysis was also run by the selected area electron diffraction pattern (SAEDP). The experiments in the calorimeter were carried out at room temperature with acetic acid as the calorimetric solvent. The enthalpy of the lithium's reaction with the acetic acid was measured and it equaled −261.1±1.6kJ/g·atom. The formation enthalpy value Δf H for the Li22Si5 compound was equal to −24.4±3.0kJ/g·atom.
Thermal energy storage has recently attracted increasing interest related to thermal applications such as space and water heating, waste heat utilization, cooling and air-conditioning. Energy storage is essential whenever there is a mismatch between the supply and consumption of energy. Use of phase change material (PCM) capsules assembled as a packed bed is one of the important methods that has been proposed to achieve the objective of high storage density with higher efficiency. A proper designing of the thermal energy storage systems using PCMs requires quantitative information about heat transfer and phase change processes in PCM. This paper reviews the development of available latent heat thermal energy storage technologies. The different aspects of storage such as material, encapsulation, heat transfer, applications and new PCM technology innovation have been carried out.
The improvement of redox-flow batteries requires the development of chemically stable and highly conductive separators. Porous glass membranes can be an attractive alternative to the nowadays most common polymeric membranes. Flat porous glass membranes with a pore size in the range from 2 to 50 nm and a thickness of 300 and 500 μm have been used for that purpose. Maximum values for voltage efficiency of 85.1%, coulombic efficiency of 97.9% and energy efficiency of 76.3% at current densities in the range from 20 to 60 mA cm−2 have been achieved. Furthermore, a maximum power density of 95.2 mW cm−2 at a current density of 140 mA cm−2 was gained. These results can be related to small vanadium crossover, high conductivity and chemical stability, confirming the great potential of porous glass membranes for vanadium redox-flow applications.
Within the obesity literature, focus is put on the link between weight status and gross motor skills. However, research on fine motor skills in the obese (OB) childhood population is limited. Therefore, the present study focused on possible weight related differences in gross as well as fine motor skill tasks. Thirty-four OB children (12 ♀ and 22 ♂, aged 7–13 years) were recruited prior to participating in a multidisciplinary treatment program at the Zeepreventorium (De Haan, Belgium). Additionally, a control group of 34 age and gender-matched healthy-weight (HW) children was included in the study. Anthropometric measures were recorded and gross and fine motor skills were assessed using the Bruininks–Oseretsky Test of Motor Proficiency, second edition (BOT-2). Results were analyzed by independent samples t-tests, multivariate analysis of variance, and a chi-squared test. Being OB was detrimental for all subtests evaluating gross motor skill performance (i.e., upper-limb coordination, bilateral coordination, balance, running speed and agility, and strength). Furthermore, OB children performed worse in fine motor precision and a manual dexterity task, when compared to their HW peers. No group differences existed for the fine motor integration task. Our study provides evidence that lower motor competence in OB children is not limited to gross motor skills alone; OB children are also affected by fine motor skill problems. Further investigation is warranted to provide possible explanations for these differences. It is tentatively suggested that OB children experience difficulties with the integration and processing of sensory information. Future research is needed to explore whether this assumption is correct and what the underlying mechanism(s) could be.
We have investigated magnetite (Fe3O4) as an electroactive battery electrode material, where a linear relationship was observed between Fe3O4 crystallite size and capacity, with a negative slope. In order to better understand this novel relationship, we report here the Rietveld refinement and X-ray absorption spectroscopy (XAS) investigation of nanosized Fe3O4 as a function of crystallite size (7–26nm). Rietveld refinement established that the Fe3O4 samples were phase pure, while the extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) provided insight into the local geometries and electronic structure of the iron centers, including oxidation state assignment. From our current and recent studies, we suggest that the surface of the Fe3O4 crystallites is rich in Fe3+, thus as the Fe3O4 crystallite size decreases, the electrochemical capacity increases, due to a net enrichment of Fe3O4 in Fe3+.
A zinc air fuel cell (ZAFC) stack with inexpensive manganese dioxide (MnO2) as the catalyst is designed, in which the circulation flowing potassium hydroxide (KOH) electrolyte carries the reaction product away and acts as a coolant. Experiments are carried out to investigate the characteristics of polarization, constant current discharge and dynamic response, as well as the factors affecting the performance and uniformity of individual cells in the stack. The results reveal that the peak power density can be as high as 435 mW cm−2 according to the area of the air cathode sheet, and the influence factors on cell performance and uniformity are cell locations, filled state of zinc pellets, contact resistance, flow rates of electrolyte and air. It is also shown that the time needed for voltages to reach steady state and that for current step-up or current step-down are both in milliseconds, indicating the ZAFC can be excellently applied to vehicles with rapid dynamic response demands.
This paper presents a comparative analysis of novel supervised fuzzy adaptive resonance theory (SF-ART), multilayer perceptron (MLP) and Multi Layer Perceptrons (MLP) neural networks over Ballistocardiogram (BCG) signal recognition. To extract essential features of the BCG signal, we applied Biorthogonal wavelets. SF-ART performs classification on two levels. At first level, pre-classifier which is self-organized fuzzy ART tuned for fast learning classifies the input data roughly to arbitrary (M) classes. At the second level, post-classification level, a special array called Affine Look-up Table (ALT) with M elements stores the labels of corresponding input samples in the address equal to the index of fuzzy ART winner. However, in running (testing) mode, the content of an ALT cell with address equal to the index of fuzzy ART winner output will be read. The read value declares the final class that input data belongs to. In this paper, we used two well-known patterns (IRIS and Vowel data) and a medical application (Ballistocardiogram data) to evaluate and check SF-ART stability, reliability, learning speed and computational load. Initial tests with BCG from six subjects (both healthy and unhealthy people) indicate that the SF-ART is capable to perform with a high classification performance, high learning speed (elapsed time for learning around half second), and very low computational load compared to the well-known neural networks such as MLP which needs minutes to learn the training material. Moreover, to extract essential features of the BCG signal, we applied Biorthogonal wavelets. The applied wavelet transform requires no prior knowledge of the statistical distribution of data samples.
The effect of polyaspartate (PASP) on the performance of the lead-acid negative plate has been investigated. It was established that this polymer additive controls the crystallization process of lead sulphate and modifies the shape and size of PbSO4 crystals. The addition of PASP to the negative paste and to the electrolyte improves the utilization of the negative active material and reduces the internal resistance of the negative plates. The results obtained during cycling of lead-acid cells under simple simulated HRPSoC cycling duty with 2C discharge current show that addition of PASP improves the cycling ability of the negative plates and thus decreases the frequency of equalization charging during operation. A beneficial effect on the performance of lead-acid batteries was observed during HRPSoC cycling of flooded batteries with 0.1% PASP in the electrolyte. The addition of PASP leads to formation of smaller PbSO4 crystals, which are more easily reduced during charge and hence prevents the accumulation of large lead sulphate crystals on the negative plates in HRPSoC duty.
We have developed a Si/graphene oxide electrode synthesized via ultrasonication-stirring method under alkaline condition. Scanning electron microscopy (SEM), transmission electron microscope (TEM), EDS dot-mapping and high-resolution transmission electron microscopy (HRTEM) results show that Si particles are evenly dispersed on the graphene oxide sheets. The electrochemical performance was investigated by galvanostatic charge/discharge tests at room temperature. The results revealed that Si/graphene oxide electrode exhibited a high reversible capacity of 2825mAh/g with a coulombic efficiency of 94.6% at 100mA/g after 15 cycles and a capacity retention of 70.8% after 105 cycles at 4000mA/g. These performance parameters show a great potential in the high-performance batteries application for portable electronics, electric vehicles and renewable energy storage.