batterydata/paper-abstracts huggingface dataset:
Nickel-rich lithium nickel cobalt manganese oxides have received considerable attention as a promising cathode material, however, they have suffered from poor interfacial stability, especially at high temperature. Here, we suggest a bi-functionalized divinyl sulfone that enhances the applicability of a nickel-rich cathode via stabilization of the electrolyte–electrode interface. The divinyl sulfone forms a protective layer on the cathode surface by electrochemical oxidation reactions and this greatly decreases the internal pressure of the cell via stabilization of the Ni-rich cathode–electrolyte interface. The cell controlled with divinyl sulfone shows remarkable cycling performance with 91.9% capacity retention at elevated temperature even after 100 cycles. Additional electrode analyses and first-principles calculations provide critical spectroscopic evidences to demonstrate the combined effects of the sulfone and vinyl functional groups. Once the divinyl sulfone is electrochemically oxidized, the vinyl functional groups readily participate in further stabilizing sulfone-based solid electrolyte interphase intermediates and afford a durable protective layer on the nickel-rich electrode surface.
Although hard carbons are considered to be applied as promising anode materials for sodium-ion batteries (SIBs) with improved specific capacity and good long-term cycle life. However, a significant low initial Coulombic efficiency (ICE) and high cost that consequently impede its use in future commercialization of SIBs. Herein, a cost effective strategy is used to prepare the large-scalable hard carbon (HC) anode material for SIBs, which shows excellent initial reversible capacity of 308 mA h g−1 under the current rate of 50 mA g−1 and considerable higher ICE of 78%. After more than 300 cycles, the material exhibits a specific capacity of 160 mA h g−1 and presenting superior capacity retention more than 94% under current density of 500 mA g−1. The obtained results establish a new technique to construct low cost hard carbon based anode materials for next-generation high performance SIBs.
A NiCo2S4 nanoparticles composite, in-situ grown on rice husk hierarchical porous carbon, is synthesized through a facile one-step hydrothermal method for energy storage. The NiCo2S4 nanoparticles with a size of 20 ± 10 nm are homogeneously distributed on the carbon matrix, leading to a high material utilization and high capacity, significantly outperformed the pure NiCo2S4. The chemical bonds of C-O-Co and C-O-Ni between the NiCo2S4 nanoparticles and the carbon matrix not only result in a superior power density, but also improve the cycling stability. An asymmetrical supercapacitor is assembled using the composite material and commercial YP-50 activated carbon and shows high energy density, high power density and excellent cycling stability. The hydrothermal method can be extended to synthesize other composite materials for energy storage devices.
A battery swapping and charging station (BSCS) is an energy refueling station, where (i) electric vehicles (EVs) with depleted batteries (DBs) can swap their DBs for fully-charged ones, and (ii) the swapped DBs are then charged until they are fully-charged. Successful deployment of a BSCS system necessitates a careful planning of swapping- and charging-related infrastructures, and thus a comprehensive performance evaluation of the BSCS is becoming crucial. This paper studies such a performance evaluation problem with a novel mixed queueing network (MQN) model and validates this model with extensive numerical simulation. We adopt the EVs’ blocking probability as our quality-of-service measure and focus on studying the impact of the key parameters of the BSCS (e.g., the numbers of parking spaces, swapping islands, chargers, and batteries) on the blocking probability. We prove a necessary and sufficient condition for showing the ergodicity of the MQN when the number of batteries approaches infinity, and further prove that the blocking probability has two different types of asymptotic behaviors. Meanwhile, for each type of asymptotic behavior, we analytically derive the asymptotic lower bound of the blocking probability.
This study examined the degree to which reinforcement, stimulant medication, and their combination impact response inhibition in children with Attention-Deficit/Hyperactivity Disorder (ADHD). Across three studies, participants with ADHD (n = 111, 25 girls) and typically-developing (TD) controls (n = 33, 6 girls) completed a standard version of the stop signal task (SST) and/or a reinforcement-manipulation SST with performance-contingent points. In two of these studies, these tasks were performed under placebo or 0.3 and 0.6 mg/kg methylphenidate (MPH) conditions. Cross-study comparisons were conducted to test hypotheses regarding the separate and combined effects of reinforcement and methylphenidate on response inhibition among children with ADHD relative to TD controls. Baseline response inhibition was worse among children with ADHD compared to controls. MPH produced dose-related improvements in response inhibition in children with ADHD; compared to non-medicated TD controls, 0.3 mg/kg MPH normalized deficient response inhibition, and 0.6 mg/kg MPH resulted in better inhibition in children with ADHD. Reinforcement improved response inhibition to a greater extent for children with ADHD than for TD children, normalizing response inhibition. The combination of MPH and reinforcement improved response inhibition among children with ADHD compared to reinforcement alone and MPH alone, also resulting in normalization of response inhibition despite repeated task exposure. Deficient response inhibition commonly observed in children with ADHD is significantly improved with MPH and/or reinforcement, normalizing inhibition relative to TD children tested under standard conditions.
To overcome the detrimental effects of LiFePO4 on the tap density and volumetric energy density accompanied by conventional carbon-based additives, C-LiFePO4/graphene was successfully prepared via hydrothermal synthesis, followed by heat treatment, and by substitution of superior conductive graphene nanosheets for some conventional carbon. The reduction of graphite oxide and the synthesis of LiFePO4 were carried out simultaneously in mixed ethylene glycol/water medium, facilitating desirable compatibility and architecture of LiFePO4 particles and graphene nanosheets. Due to the synergism of thin carbon coating and graphene matrix with low fraction on the basis of complementary advantages, C-LiFePO4/graphene exhibits superior high-rate performance and favorable energy density, which with a unique structural and geometrical feature that LiFePO4/C nanorods embedded in a matrix built of interweaved graphene nanosheets. The dual coatings exert a significantly energetic impact on the electronic conductivity and lithium ion transport, thus novel composite presented excellent electrochemical properties, which was achieved with reversible capacities of 100 mAh/g at 20C and 80 mAh/g at 50C, while preserving a high tap density of 1.76g/cm3.
Poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate) (PTMA) displays a two–electron process redox reaction, high capacity of up to 222 mA h g−1, good rate performance and long cycle life, which is promoted by graphene as cathode material for lithium rechargeable batteries.
A facile hydrothermal process with hexadecyltrimethyl ammonium bromide (CTAB) as the soft template is proposed to tune the morphology and size of cobalt hydroxide (Co(OH)2). Monodisperse β-phase Co(OH)2 nanowires with uniform size are obtained by controlling the CTAB content and the reaction time. Due to the uniform well-defined morphology and stable structure, the Co(OH)2 nanowires material exhibits high capacitive performance and long cycle life. The specific capacitance of the Co(OH)2 nanowires electrode is 358 F g−1 at 0.5 A g−1, and even 325 F g−1 at 10 A g−1. The specific capacitance retention is 86.3% after 5000 charge–discharge cycles at 2 A g−1. Moreover, the asymmetric supercapacitor is assembled with Co(OH)2 nanowires and nitrite acid treated activated carbon (NTAC), which shows an energy density of 13.6 Wh kg−1 at the power density of 153 W kg−1 under a high voltage of 1.6 V, and 13.1 Wh kg−1 even at the power density of 1.88 kW kg−1.
Smart camera networks are real-time distributed embedded systems that perform computer vision using multiple cameras. This new approach has emerged thanks to a confluence of simultaneous advances in four key disciplines: computer vision, image sensors, embedded computing, and sensor networks. In this chapter, we briefly review and classify smart camera platforms and networks into single smart cameras, distributed smart camera systems, and wireless smart camera networks. We elaborate the vision of pervasive smart camera networks and identify major research challenges. As the technology for these networks advances, we expect to see many new applications open up—transforming traditional multi-camera systems into pervasive smart camera networks.
This paper presents an approach to the energy management and control of the effective cost of energy in real-time electricity pricing environment. The strategy aims to optimise the overall energy flow in the electrical system that minimises the cost of power consumption from the grid. To substantiate these claims different cases of time-of-use (TOU) and renewable energy electricity tariff, i.e. in summer and winter seasons, and the robustness of system is analysed. A given energy demand for commercial usage in the city of Tshwane (South Africa) is used to investigate the behaviour of the designed method during low and high demand periods. As grid integrated renewable energy resources, photovoltaic (PV) is an important consideration in assuring excellent power supply and environmental issues in the commercial building. An adaptive optimal approach in the framework of model predictive control (MPC) is designed to coordinate the energy flow on the electrical system. The results show that the proposed adaptive MPC strategy can promote the new approach of an optimal electrical system design, which reduces the energy cost to pay the utility grid by about 46% or more depending on the set target.
Socioeconomic status is associated with cognitive development, but the extent to which this reflects neuroanatomical differences is unclear. In 1,099 children and adolescents, family income was nonlinearly associated with brain surface area, and this association was greatest among disadvantaged children. Further, surface area mediated links between income and executive functioning.
All-solid-state cells were fabricated using Cu x Mo6S8−y Chevrel-phase as an active material and Li2S–P2S5 glass–ceramics as a solid electrolyte. The cells showed good cycle performance with a constant capacity of about 100mAhg−1 for 2000 cycles at the current density of 1.28mAcm−2 at room temperature. The reaction mechanism in the all-solid-state cells was investigated using X-ray diffraction (XRD). The XRD pattern after the 100th charge was almost identical to that before cycling; it is therefore considered that the retention of the crystal structure during cycling brings about a good cycle performance. The use of Cu x Mo6S8−y as an electrode and Li2S–P2S5 glass–ceramics as a solid electrolyte led to the formation of a good solid–solid interface using impedance spectroscopy. All-solid-state cells using Cu x Mo6S8−y as an active material and the 70Li2S·30P2S5 (mol%) glass–ceramic as a solid electrolyte worked at a high current density of 12.8mAcm−2 at a high temperature of 160°C and retained a reversible capacity of about 270mAhg−1 for 10 cycles.
A potential positive electrode material, α-NaFeO2, can be viewed one of the base material for rechargeable Na batteries. In this study, we found that its structural evolution during charge process differentiates depending on its synthesis route. The α-NaFeO2 is prepared by three methods: one is by the hydrothermal technique (HT), and the other two by solid-state reactions, SSn and SS μ , in which nano-sized Fe3O4 and micro-sized Fe3O4 are used as the Fe source, respectively. The synchrotron radiation X-ray diffraction profiles of the initial state suggest that all three samples are apparently identified as the target product, α-NaFeO2, with rhombohedral structures. Though all three samples remain stable for more than 50 cycles under the cycling conditions of a constant amount of charging (Na extraction) to 70mAhg−1, their structural evolution differs during the sodium extraction. The SS μ transitions from the rhombohedral structure to a spinel-like cubic structure, while the HT transforms into a monoclinic structure. On the other hand, both the monoclinic and cubic phases co-exist in SSn. What produces these differences among the seemingly identical materials is discussed.
If photovoltaic solar cells and modules are to be used as a major source of power generation it is important to have a good knowledge and understanding of their long-term performance under different climatic and operating conditions. A number of studies of the long-term performance of commercially available photovoltaic modules manufactured using different technologies have now been reported in the literature. These have shown clear differences in the seasonal and long term performance and stability of different solar cell techniques. In addition to general module engineering factors that result in a loss of performance in all modules some types of solar cells, such as those made from thin film amorphous silicon (a-Si:H), also suffer specific losses in performance due to fundamental material changes, such as photodegradation or the Staebler–Wronski effect (SWE). A field evaluation of the long term performance of state-of-the-art crystalline and amorphous silicon photovoltaic modules in Australian conditions is currently being undertaken at Murdoch University. The initial results from this monitoring program are reported. This paper also reports on laboratory and field studies being undertaken on the nature of the Staebler–Wronski effect in amorphous silicon solar cells and how the stability of these cells is affected by different operating conditions. Based on a mechanism for the SWE in a-Si:H solar cells developed as a result of our research we propose a number of possible ways to reduce the Staebler–Wronski effect in a-Si:H solar cells.
Lead dioxide thin films were electrodeposited on gold substrates and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mass change occurring upon immersion in a H2SO4 electrolyte and during electrochemical reduction was observed in situ by electrochemical quartz crystal microbalance (EQCM). A hydrated PbO2 gel-type layer is formed at the surface of electrodeposited PbO2. The concentration of the H2SO4 electrolyte does not affect the composition of the gel nor the amount of lead dioxide involved in the hydration process. It is established that 1.3×10−7 molcm−2 of β-PbO2 are hydrated at the surface of an electrodeposited film and that the hydration reaction occurs according to the following reaction: PbO2 (crystal) + xH2O↔(PbO(OH)2·(x −1)H2O)(gel), where x =8.1. The mass change occurring during the first and subsequent discharge of PbO2 was recorded. It is shown that both PbO2 (crystal) and PbO(OH)2·(7.1)H2O)(gel) are reduced to PbSO4 during the first discharge.
The pure-phase Li1.2V3O8 was synthesized by ultrasonically dispersing Li2CO3 and NH4VO3 reactants. Its structure and morphology compared with the pristine Li1+x V3O8 obtained from the solid-state reaction were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the compound synthesized at 570°C from the precursor obtained by ultrasonic treatment in anhydrous ethanol has low crystallinity and homogeneous morphology with bar-like shape. Charge–discharge cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments indicate that this sample has relatively high initial discharge capacity and good cycle ability, and it is beneficial to the reversible insertion/extraction of Li+ ions because of the low kinetic resistance. Its discharge capacity reaches 270mAhg−1 in the 2nd cycle at 0.2C discharge rate and still retains 210mAhg−1 in the 100th cycle in the range of 2.0–4.0V.
This paper presents an energy management strategy to operate a hybrid power system with renewable sources (wind and solar), batteries, and polymeric electrolyte membrane fuel cells. The fuel cells are fed with hydrogen from bioethanol reforming. The energy management strategy uses the concept of receding horizon with predictions of the future generation from the renewable sources, the future load, and the state of charge in the battery bank. Several tests are done in order to analyze the performance of the proposed methodology. The results, compared with the case without predictions, show a reduction in the loss of power supply probability (LPSP) up to 88%.
Experiments with silicon-oxycarbide, an anode material for Li-ion batteries, are compared with a rigorous solution for time-dependent diffusion profiles in spherical particles, which is supplemented by finite element analyses of cuboid shaped particles. In this way a value for the chemical diffusivity D = 1.8 × 10−18–4.2 × 10−18 m2 s−1 across the entire range of the state-of-charge is obtained. The method consists of galvanostatic titrations, where a constant current injection is followed by the measurement of the galvanic potential in open circuit relaxation, at various values of the state-of-charge. Comparison with theory shows that the relaxation time varies with the state-of-charge because the particles have variable size: small particles have short relaxations and dominate the low values of the state-of-charge. The theoretical results have additional notable features. We show that the solution for the spherical particles can be represented to a very good approximation by a single time constant of exponential relaxation. Its value is significantly slower than the results for one-dimensional solutions. The relaxation time is independent of the injection current and the state-of-charge, imparting significant generality to the results.
Binary metal compounds have higher conductivity and richer redox reactions due to the co-existence and synergism of different transition metals. Besides, carbon in composite materials has the advantage of enhancing electronic conductivity to promote fast electron transmission. Herein, a series of NimPn/C, Ni2P/C, Co2P/C and NixCo2-xP/C nanohybrids with different Ni/Co molar ratios were synthesized by in-situ calcination/phosphorization of MOF precursors. These nanohybrid materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive spectrometer and electrochemical tests. The NiCoP/C material possesses a granular structure with NiCoP nanoparticles anchored in a large number of carbon. Taking advantage of the bimetallic synergism and carbon anchoring effect, the as-prepared NiCoP/C sample delivers the most prominent specific capacities of 775.7C g−1 at 1 A g−1, and 582.4C g−1 at 20 A g−1 (20-fold) with a superior rate capability of 75.1% retention, much superior to those of the corresponding NimPn/C, Ni2P/C, Co2P/C, other NixCo2-xP/C samples and various reported metal phosphide nanostructures/nanocomposites. Furthermore, the constructed NiCoP/C//activated carbon asymmetric supercapacitor can exhibit a high energy density of 47.6 Wh kg−1 at a power density of 798.9 W kg−1, which was superior to those previously reported of Ni/Co phosphide nanomaterials.
Daytime sleepiness is associated with several medical problems. The aim of this paper is to provide normative values for one of the most often used questionnaires measuring daytime sleepiness, the Epworth Sleepiness Scale (ESS).
This paper presents a mathematical model built for analyzing the intricate thermal behavior of a 18650 LCO (Lithium Cobalt Oxide) battery cell during thermal runaway when venting of the electrolyte and contents of the jelly roll (ejecta) is considered. The model consists of different ODEs (Ordinary Differential Equations) describing reaction rates and electrochemical reactions, as well as the isentropic flow equations for describing electrolyte venting. The results are validated against experimental findings from Golubkov et al. [1] [Andrey W. Golubkov, David Fuchs, Julian Wagner, Helmar Wiltsche, Christoph Stangl, Gisela Fauler, Gernot Voitice Alexander Thaler and Viktor Hacker, RSC Advances, 4:3633–3642, 2014] for two cases - with flow and without flow. The results show that if the isentropic flow equations are not included in the model, the thermal runaway is triggered prematurely at the point where venting should occur. This shows that the heat dissipation due to ejection of electrolyte and jelly roll contents has a significant contribution. When the flow equations are included, the model shows good agreement with the experiment and therefore proving the importance of including venting.
Polyaniline (PANI) is one of the most widely used organic electrode materials for supercapacitors. It has advantages such as good environmental stability and low cost, whereas it is difficult to achieve high capacitance, good rate capability and long cycle life simultaneously. In this work, a series of porous polyaniline/carbon nanotube (PANI/CNT) composite materials are prepared by chemically grafting PANI on CNTs and creating interpenetrating pores via templating using CaCO3 nanoparticles, and then studied as electrode materials for supercapacitors. As PANI is covalently grafted on CNT networks formed in the electrode, the delocalization of electrons improves electron transport in the electrode and the stability of PANI in redox cycling process. The porous morphology created provides sufficient channels for the transport of ions. As a result, the optimized PANI/CNT composite exhibits a high capacitance of 1266 F g−1 at a specific current of 1 A g−1, and even at a specific current of 128 A g−1 the specific capacitance could reach 864 F g−1. Moreover, after cycling tests of 10,000 cycles, it remains 83% of its capacitance at the first cycle. The excellent rate performance and cycle stability of the porous PANI/CNT composite makes it a promising high-performance electrode material for supercapacitors.
The identification of catalytically active and stable bifunctional electrocatalysts for the oxygen reduction and evolution reaction (ORR/OER) would revolutionize rechargeable metal-air batteries and regenerative fuel cell technologies. In this study, we use density functional theory (DFT) calculations to systemically investigate 2D transition metal based tetracyanoquinodimethane (TM–TCNQ, TM = Cr-Cu, Ru-Ag, Pt, Ir) monolayers with single TM atoms catalysts (SACs) distributed periodically with high density. We calculate a lower limiting overpotential of ηlim = 0.33 V for Fe-TCNQ yielding a higher expected activity than that of Pt metal (0.48 V) for the ORR under acidic conditions. The catalytic performance of Fe-TCNQ for OER is, however, surpassed by Ni-TCNQs (ηlim = 0.46 V), which is identified as the highest among the candidates. By applying grafting axial ligands and external strain, the adsorption strength of reaction intermediates on TM reactive sites can be further optimized and enhances the activities of Mn-, Fe- and Ni-TCNQs for the ORR or the OER. Here, Fe-TCNQ-Cl (ηlim = 0.27/0.55 V), followed by Fe-TCNQ-CO (ηlim = 0.67/0.43 V), are predicted as novel, high-performance bifunctional ORR/OER catalysts with comparable limiting overpotentials to those of the best commercially used electrocatalysts, Pt (ORR: ηlim = 0.48 V) and RuO2 (OER: ηlim = 0.42 V). In addition, the recently synthesized Fe-TCNQ possess excellent conductivity with fast electron transfer during the catalytic reactions. These results show 2D TM-TCNQ monolayers are durable, low-cost, and efficient catalysts for the ORR and the OER in metal-air batteries and fuel cells.