batterydata/paper-abstracts huggingface dataset:
Lithium difluorophosphate (LiPO2F2) was used as an electrolyte additive to promote the low temperature performance of LiNi0.5Co0.2Mn0.3O2/graphite cells. The impact of LiPO2F2 on the solid electrolyte interface (SEI) film-formation on electrodes was demonstrated by various electrochemical methods and microscopy techniques, such as transmission electron microscopy (TEM), scanning electron microscope (SEM) as well as X-ray photoelectron spectroscopy (XPS), in the pouch cells and half cells. The results showed that the cells containing 1% LiPO2F2 performed 71.9% (−20°C) and 57.93% (−30°C) of initial capacity, while the cells without LiPO2F2 discharged only 49.41% and 9.6% of initial capacity under the same condition. In addition, the enhancement of cyclic performance at 0°C was attributed to a conductive and stable SEI film formed on the graphite by the sacrifice of LiPO2F2, which led to a low impedance and richer content of LiF and Li2CO3 in SEI components, as depicted in XPS.
Aluminium alloys containing small additions of both tin (∼0.1wt%) and gallium (∼0.05wt%) are shown to dissolve anodically at high rates in sodium chloride media at room temperatures; current densities >0.2Acm−2 can be obtained at potentials close to the open circuit potential, ∼−1500mV versus SCE. The tin exists in the alloys as a second phase, typically as ∼1μm inclusions (precipitates) distributed throughout the aluminium structure, and anodic dissolution occurs to form pits around the tin inclusions. Although the distribution of the gallium in the alloy could not be established, it is also shown to be critical in the formation of these pits as well as maintaining their activity. The stability of the alloys to open circuit corrosion and the overpotential for high rate dissolution, both critical to battery performance, are shown to depend on factors in addition to elemental composition; both heat treatment and mechanical working influence the performance of the alloy. The correlation between alloy performance and their microstructure has been investigated.
In this paper, size of a PV/wind integrated hybrid energy system with battery storage is optimized under various loads and unit cost of auxiliary energy sources. The optimization is completed by a simulation based optimization procedure, OptQuest, which integrates various heuristic methods. In the study, the main performance measure is the hybrid energy system cost. And the design parameters are PV size, wind turbine rotor swept area and the battery capacity. The case study is realized for Izmir Institute of Technology Campus Area, Urla, Turkey. The simulation model of the system is realized in ARENA 12.0, a commercial simulation software, and is optimized using the OptQuest tool in this software. Consequently, the optimum sizes of PV, wind turbine and battery capacity are obtained under various auxiliary energy unit costs and two different loads. The optimum results are confirmed using Loss of Load Probability (LLP) and autonomy analysis. And the investment costs are investigated how they are shared among those four energy sources at the optimum points.
Hierarchical hollow microflowers constructed from mesoporous single crystalline CoMn2O4 nanosheets were synthesized by a solvothermal route followed by calcination in air. It was found that the amount of deionized water plays a key role in the formation of the well-defined hierarchical hollow structure. A possible formation mechanism of the hierarchical hollow microflowers is proposed based on the time-dependent experimental results. In addition, the unique structure of CoMn2O4 microflowers exhibits superior electrochemical performances with an initial discharge specific capacity of 1024 mA h g−1 at 1000 mA g−1 and remains at 650 mA h g−1 with a coulombic efficiency of 98.7% after 500 cycles.
We report a facile synthesis of octahydroxytetraazapentacene (OHTAP) and the application of this redox-active material as a cathode for lithium- and potassium-ion batteries. While testing in lithium half-cells, OHTAP was used in the form of lithium salt and delivered the specific discharge capacity of >400 mAh g−1 and the energy density of ~700 Wh kg−1, which are impressive values achieved for organic electrode materials and can also be favorably compared with the characteristics of the current commercial benchmark cathodes based on LiFePO4 (~155 mAh g−1 and 543 Wh kg−1). The potassium half-cells fabricated using pristine OHTAP depending on the electrode deposition technique showed specific capacities of 120–220 mAh g−1, which are among the record values reported so far for this type of batteries. Quantum chemical DFT modelling provided insights in the mechanistic aspects of metallation of OHTAP and revealed that lithium- and potassium-ion storage might involve both the hydroquinone-quione chemistry as well as the redox transformations of pyrazine rings.
We describe a case of reflex seizures induced by abstract reasoning but not other cognitive processes. The patient, a 46-year-old man, experienced myoclonic seizures whenever he played shogi (Japanese chess). To identify the critical thought processes responsible for inducing his seizures, we monitored his clinical seizures and epileptiform discharges while he performed comprehensive neuropsychological tests, including the Wechsler Adult Intelligence Scale—Revised (WAIS-R), spatial working memory, mental rotation, and Wisconsin Card Sorting Test (WCST) tasks. A myoclonic seizure occurred only during the WCST. Generalized 3- to 5-Hz spike-and-slow-wave bursts occurred repeatedly during the Block Design subtest of the WAIS-R and the WCST, whereas no discharges occurred during other subtests of the WAIS-R including the calculation, spatial working memory, and mental rotation tasks. These results indicate that abstract reasoning, independent of other cognitive processes, could induce the patient’s epileptiform discharges, suggesting that his reflex seizures might be a distinct subtype of nonverbal thinking-induced seizures.
Carbon and nitrogen, (C&N), co-modified hierarchical Li4Ti5O12 (LTO) particles with excellent perfomance in lithium-ion batteries were prepared via a facile synthesis with the proper modifying of C and N successfully reducing the polarization and enhancing the conductivity of LTO while also giving rise to Ti3+ sites due to the reduction ability of C&N. Together, with primary nanocrystals less than 10nm and a relatively high specific surface area (16.9 m2 g−1), as-prepared samples exhibit excellent electrochemical performance, such as a high capacity around 174.7 mAh g−1 at the current rate of 0.1C and reversible capacity over 171 and 150 mAh g−1 after 100 cycles at the current rate of 1 and 10C (1C=175 mAh g−1). More importantly, the optimal amount of C&N modifying in LTO was investigated for the first time. It was found that excessive modifying of C&N can introduce a lot of amorphous TiONx and also create undesirable Ti2+ to induce a structural transformation of LTO, directly leading to a low rate capacity.
Tin–graphene nanocomposites are prepared by a combination of microwave hydrothermal synthesis and a one-step hydrogen gas reduction. Altering the weight ratio between tin and graphene nanosheets has critical influences on their morphologies and electrochemical performances. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) analysis confirm the homogeneous distribution of tin nanoparticles on the surface of graphene nanosheets. When applied as an anode material in lithium ion batteries, tin–graphene nanocomposite exhibits a high lithium storage capacity of 1407 mAh g−1. The as-prepared tin–graphene nanocomposite also demonstrates an excellent high rate capacity and a stable cycle performance. The superior electrochemical performance could be attributed to the synergistic effect of the three-dimensional nanoarchitecture, in which tin nanoparticles are sandwiched between highly conductive and flexible graphene nanosheets.
The remarkable recent progress in computing power, sensors and embedded devices, smart phones, wireless communications and networking technologies, combined with emerging data mining techniques, cloud computing and social networking paradigms has enabled us to create pervasive computing systems and services with diverse applications and global accessibility. In this paper, we assess the current state of the art of pervasive computing at scale (PeCS) and look ahead to future directions the field can pursue together with challenges it will need to overcome.
Understanding the physical mechanisms by which blast waves interact with their surroundings is paramount to protecting the safety of armed service personnel and equipment. This study evaluates and discusses modern technology used in blast pressure measurement as it relates to primary blast injuries such as traumatic brain injury. Factors influencing primary blast injury were established as peak overpressure, impulse, number, and frequency of shock impacts based on a literature review. A simulated confined-corridor breaching environment was used to establish the potential for variability in these key parameters depending on location in a confined blast environment. Wearable blast pressure monitors were compared experimentally to not only laboratory grade pressure transducers but also simulated and empirically modeled blast pressure and impulse predictions at scaled distances between 3.1 and 13.6m/kg1/3
Traumatic brain injury (TBI) is one of the most commonly reported injuries in armed service members returning from combat zones [1, 2]. Approximately one-quarter of service members returning from deployment report sustaining a TBI with 60% of these cases attributed to primary blast injury, injury from shock overpressure resulting from blast exposure. A recent study by the United States Marine Corps indicates a steady rise in the number of reported TBI cases between 2015 and 2019, with as many as 14,000 Marines reporting at least one TBI, and 5600 reporting multiple [3].
Submicron-sized Li4Ti5O12/Li2TiO3 composites with Li-rich grain boundaries are successfully synthesized by a simple, environmentally benign, mass production preferred solid state process. The crystal phase and morphology are characterized by XRD and SEM. The electrochemical performance is collected by galvanostatic discharge–charge tests, cyclic voltammograms (CV) and electrochemical impedance spectra (EIS) tests. The initial discharge capacity of Li4Ti5O12/Li2TiO3 composite is 155 mAh g−1 at 0.5 C. While the current rate is as high as 10 C, the specific capacity is 113 mAh g−1, and the capacity retention is 98.2% even after 500 cycles. As a reference, the ionic conductivity and the electrochemical performance of Li2TiO3 and Li4Ti5O12/TiO2 composite are also characterized. The extraordinary high rate performance and cycling stability are explained by high ionic conductivity and rich grain boundaries of Li4Ti5O12/Li2TiO3 composite.
To improve the freeze start ability of a fuel cell system some significant influencing parameters are defined and investigated. Experiments with a fuel cell test system are carried out in a climate chamber at various conditions. The time interval until fuel cell stack power equals 50% of its maximum power is defined as an indicator for a successful freeze start as well as a value for comparison and evaluation of the results. The target of this work is the minimization of this freeze start time by avoiding the freezing of process water on the catalyst layer of the Membrane Electrode Assembly (MEA), since this leads to temporary performance losses. The shut down strategy of the fuel cell system is identified to be one of the main parameters influencing the freeze start. It is found that a higher degree of dryness in the stack leads to a significant improvement in the freeze start performance, since the water absorbing capacity of the membrane increases and therefore also the time until its saturation. If this saturation takes place after the temperature of the MEA reached 0°C, no significant ice-formation occurs. It is shown that by improving the shut down strategy of the fuel cell system at T Start =−6°C a start without performance loss can be realized. At temperatures lower than that temporary performance losses occur. Even if a lower voltage leads to a higher current and therefore to a higher water production rate, its effect on the freeze start due to the increased heat of reaction is positive. Further investigated parameters, for example the volume of the coolant loop, also affect the freeze start ability, but it can be concluded that the shut down strategy is of main importance.
In an attempt to provide a Si material having a long cycle life as an anode of Li-ion batteries, we prepared a metallic Si film on a Ni foil by a vacuum evaporation method. Due to the presence of a naturally formed compact passivation film on the Ni foil, a homogeneous, compact amorphous-like Si film strongly adhering to the Ni substrate could be obtained very easily. The Si film thus obtained on a Ni foil was evaluated electrochemically with cyclic voltammetry (CV) and constant current charge/discharge cycle test (CT) in two types of solvents containing 1M LiClO4, i.e. propylene carbonate (PC), and a 1:1 (v/v) mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC). Two strong peaks were observed on the anodic branch of the CV at 300mV (versus Li/Li+) and 500mV and the constant current discharge curve of CT produced a wide plateau at around 400mV in EC/DMC with a discharge capacity of 1700–2200mAh/g at a discharge rate of 2C. Nearly the same performance was observed as well in PC, where no solvent decomposition was detected. The capacity depended on the preparation conditions and the film thickness. The cycleability at 2C charge/discharge rate was over 750 cycles. One of the important issues to solve is to reduce the large initial charge loss.
Previous studies have utilized a lesion model of cortical injury that produces transient behavioral impairments to investigate the recovery of function process. To better understand the recovery process, it would be beneficial to use a lesion model that produces more severe, enduring, behavioral impairments. The purpose of experiment 1 was to validate whether large lesions of the sensorimotor cortex (SMC), which included the rostral forelimb and caudal forelimb regions, produced enduring behavioral deficits. Rats were given large unilateral electrolytic lesions of the SMC, administered either the N-methyl-D-aspartate (NMDA) antagonist, MK-801 or saline 16 h after injury, and tested on a battery of behavioral tests. Enduring behavioral deficits were observed, for at least 6 months, on two tests of forelimb placing while transient deficits were observed on the foot-fault and somatosensory neutralization tests. Administration of MK-801 facilitated recovery on the somatosensory neutralization test; however, it did not induce recovery on either forelimb placing test. A second experiment was performed to determine if earlier administration of MK-801, the NMDA antagonist magnesium chloride (MgCl2), or the anti-oxidant N-tert-butyl-α-phenylnitrone (PBN) could induce behavioral recovery in this chronic model. Treatment with these drugs induced behavioral recovery on the forelimb placing tests, whereas, the saline-treated rats did not show any signs of behavioral recovery for at least 3 months. Anatomical analysis of the striatum showed that MK-801 and MgCl2 but not PBN reduced the extent of lesion-induced striatal atrophy. These results suggest that administration of MK-801, MgCl2, or PBN shortly after cortical injury can induce recovery of function when recovery is otherwise not expected in un-treated rats.
A new core-shell nanostructure of CoO@MnO2nanowire@nanosheetarrays(NNSs) was designed and directly grown on a 3D nickel foam by a simple two step solution method combined with a post annealing treatment in Ar gas. The MnO2 nanosheets can grow directly on the CoO precuor nanowires without any pretreatment, and its thickness on the CoO nanowire arrays (NAs) can also be tailored by easily adjusting the second step hydrothermal time. When acting as a electrochemical supercapacitor, the CoO@MnO2 NNAs delivers a highly enhanced specific capacitance of 3.03Fcm−2 (about 1515Fg−1) with a wide potential window of 0.8V at 2.0mAcm−2, which is superior to most reported Co3O4 based core-shell NNAs supercapacitive electrodes. An asymmetric supercapacitor devices based on these CoO@MnO2 NNAs and aqueous electrolyte showed with a high-energy density of 0.37mWhcm−2 at a power density of 1.7mWcm−2, a high power density of 34.4mWcm−2 at 0.20mWhcm−2 and a long-term cycling ability, implying its great potential application in high-performance electrochemical supercapacitor.
Triboelectric nanogenerator (TENG) technology is an emerging new mechanical energy harvesting technology with numerous advantages. Amongst the multitude of TENG designs, the grating structure is not only the most promising for ultra-high output power but also the most complicated. In this manuscript, the first theoretical model of the grating structured TENG is presented with in-depth interpretation and analysis of its working principle. Two different categories of grating structured TENGs – grating structured TENGs with equal plate-length and with unequal plate-length are discussed in detail to illustrate their difference in output characteristics. Then for each of these two categories, a study of the basic output profiles and an in-depth discussion on the influence of the electrode structure, number of grating units, and thickness of the dielectric layers were made to obtain a strategy for optimization.
Carbon coating and iron phosphides of high electron conductivity were introduced into the LiFePO4 materials which were derived via a sol–gel method in order to improve the high discharge rate performance. The start constituents were FeC2O4·2H2O, LiOH·H2O, NH4H2PO4 and ethylene glycol. Effects of the calcination temperature and the ethylene glycol on the structure and the electrochemical performance of the LiFePO4 materials were investigated. Structure analyses showed that the addition of ethylene glycol caused an obvious decrease in the particle size of LiFePO4. Calcination temperature and ethylene glycol jointly affected the formation of iron phosphides. Combining the electrochemical testing, it was found that, at low discharge rate, small particle size and high content of LiFePO4 were much important for the capacity rather than the iron phosphides, and relative high content of Fe2P (e.g. 8wt.%) even worsened the capacity. However, with the increase of the discharge rate, the high electron conductive iron phosphides turned to play important role on the capacity. Fe2P effectively increased both the reaction and diffusion kinetics and hence enhanced the utilization efficiency of the LiFePO4 at high discharge rate. Combining relative small particle size, even 2wt.% of iron phosphides could improve the high rate performance of LiFePO4/C significantly.
Organic compounds containing S–S bonds can act as alternative cathode materials for lithium-sulfur battery to achieve high electrochemical performance through warding off the polysulfide shuttle. But most of them are less competitive due to the limited theoretical capacity and complicated synthetic process. Herein, we propose a linear molecule sulfur-rich organic material as sulfur cathode, which synthesized by prolonging the linear S–S chain in the commercial tetramethylthiuram disulfide (TMTD). The obtained tetramethylthiuram disulfide-sulfur (TMTD-S) cathode material not only possesses the unique linear structure to maintain its cycling stability, but also have a high active sulfur content to ensure its lithium storage capacity. Thus, the TMTD-S compound delivers an initial capacity of 685 mAh g−1 at 0.2C (1 C = 1061 mAh g−1) and maintains the capacity at 540 mAh g−1 after 200 cycles. Furthermore, when we improve the conductive of TMTD-S cathode material by Ketjen Black agent and carbon cloth current collector, it delivers higher initial capacity as high as 1054 mAh g−1 and retains 930 mAh g−1 after 100 cycles even at a high current density of 0.5 C and high mass loading of 1.8 mg cm−2.
In this work, we obtained improved electrochemical performance of LiNi0.5Mn1.5O4 cathode by using a monomer unit of conducting polymer, N-methylpyrrole (MPL), as an electrolyte additive. The effects of MPL on the performance of high voltage LiNi0.5Mn1.5O4 cathode were investigated via the combination of cycling test, cyclic voltammetry, electrochemical impedance spectroscopy and surface analysis. By incorporating 0.3wt% MPL into electrolyte, the capacity retention of Li/LiNi0.5Mn1.5O4 cell after 200 cycles is improved from 83.2% to 89.5% at room temperature (ca. 25°C) and from 59.1% to 87.4% at elevated temperature (55°C). Moreover, the discharge capacity of the cell with 0.3wt% MPL increase by 8% and 18% at 2C and 3C rates respectively. It is proposed that the electrochemical polymerization of MPL take place on the initial charge process and consequently create a thin, stable and conductive film on the LiNi0.5Mn1.5O4 surface. The collective effects of this cathode/electrolyte interphase (CEI) film stabilize the interface between cathode and electrolyte and alleviate the electrolyte decomposition during extended cycling, leading to improved performance of Li/LiNi0.5Mn1.5O4 cell.
A porous vanadium pentoxide (V2O5) nanomaterial was prepared by using the electrospun PMMA fibers as a template, which could be removed by annealing at high temperature leaving tube-like pores with 1μm in diameter. It is composed of numerous rice-like nanoparticles in 50–100nm size. In the potential range of 4.0–2.0V (vs. Li/Li+), it can deliver a high reversible capacity of 283mAhg−1 at 0.2C rate and exhibits an excellent rate capability (104mAhg−1 at 12C rate). Even cycled at the 4C rate, the discharge capacity still remains 85% of the initial one over 300 cycles, showing an excellent cycling performance. The results suggest the obtained V2O5 nanomaterial could develop into a promising cathode material for rechargeable lithium batteries.
The recent invention of cold sintering process (CSP) suggests a new opportunity to densify ceramic solid electrolytes at reduced temperatures. In the study, Na3.256Mg0.128Zr1.872Si2PO12 (Mg-doped NASICON) specimens were cold-sintered at 140 °C to ∼83% of the theoretical density. In addition, post-CSP annealing, at temperatures lower than that is needed for the conventional sintering of NASICON, can substantially increase the ionic conductivity (with or without significant further densification). For example, the conductivity of cold-sintered Mg-doped NASICON reached >0.5 mS/cm after annealing at (as low as) 800 °C; in comparison, a dry-pressed specimen exhibited virtually no densification at a higher temperature of 1000 °C with <0.1 mS/cm conductivity. Moreover, a high conductivity of ∼1.36 mS/cm has been achieved for a Mg-doped NASICON cold-sintered and subsequently annealed at 1100 °C (doubling the conductivity of a dry-pressed specimen sintered at the identical condition). Further mechanistic studies showed that annealing at 800–1100 °C increased the grain boundary (GB) conductivities of cold-sintered specimens. The CSP opens a new window to sinter the “thermally-fragile” ceramic solid electrolytes (such as phosphates and sulfates). In addition, it not only provides energy and cost savings but also enables new fabrication routes to make solid-state batteries.