batterydata/paper-abstracts huggingface dataset:
Single-walled carbon nanotube (SWCNT) aerogels produced by critical-point-drying of wet-gel precursors exhibit unique properties, such as high surface-area-to-volume and strength-to-weight ratios. They are free-standing, are binder-free, and can be scaled to thicknesses of more than 1mm. Here, we examine the electric double layer capacitive behavior of these materials using a common room temperature ionic liquid electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI). Electrochemical performance is assessed through galvanostatic cycling, cyclic voltammetry and impedance spectroscopy. Results indicate stable capacitive performance over 10,000 cycles as well as an impressive performance at high charge and discharge rates, due to accessible pore networks and enhanced electronic and ionic conductivities of SWCNT aerogels. These materials can find applications in mechanically compressible and flexible supercapacitor devices with high power requirements.
A phase transition from spinel Mn3O4 to layered birnessite has been reported through electrochemically induced activation in aqueous electrolyte for high performance supercapacitor, battery and water splitting applications. Here, Li2SO4, MgSO4 and K2SO4 aqueous electrolytes were used for the activation of Mn3O4 electrode to investigate the effect of electrolyte cation on the electrochemical activation. The Mn3O4 electrode exhibited different activated results in the three electrolytes, including the efficiency of phase transition, morphology of resulting birnessite and capacitive performance of the activated electrode. The cations affect the proceeding of H+ insertion or the peeling-off of birnessite nanosheets during the phase transition process, resulting in the formation of nanosheet materials with different lateral dimensions. Effect of electrolyte cation on the electrochemical behavior of nanosheets electrode is further investigated. The nanosheets electrode activated in K2SO4 exhibits capable capacitive behavior with reasonable specific capacitance and cycling stability. Understanding how different cations affect the phase transition of Mn3O4 together with its capacitive performance will conduce to the development of manganese oxide electrode systems with high performance.
Glass–ceramic Li2S–GeS2–P2S5 electrolytes were prepared by a single step ball milling (SSBM) process. Various compositions of Li4−x Ge1−x P x S4 from x =0.70 to x =1.00 were systematically investigated. Structural analysis by X-ray diffraction (XRD) showed gradual increase of the lattice constant followed by significant phase change with increasing GeS2. All-solid-state LiCoO2/Li cells were tested by constant-current constant-voltage (CCCV) charge–discharge cycling at a current density of 50μAcm−2 between 2.5 and 4.3V (vs. Li/Li+). In spite of the high conductivity of the solid-state electrolyte (SSE), LiCoO2/Li cells showed a large irreversible reaction especially during the first charging cycle. Limitation of instability of Li2S–GeS2–P2S5 in contact with Li was solved by using double layer electrolyte configuration: Li/(Li2S-P2S5/Li2S–GeS2–P2S5)/LiCoO2. LiCoO2 with SSEs heat-treated with elemental sulfur at elevated temperature exhibited a discharge capacity of 129mAhg−1 at the second cycle and considerably improved cycling stability.
Guiding inquiry learning has been shown to increase knowledge gains. Yet, little is known about the effect of guidance on attitudes and behaviours, its interaction with student attributes, and transfer of impact once guidance is removed. We address these gaps in the context of an interactive Physics simulation on electric circuits (
The article focuses on the electrochemical and optical properties of n-type conjugated polymers, containing naphthalene diimide (NDI) acceptor units in their neutral and reduced states. Cyclic voltammetry reveals significant differences between the electrochemical stability of NDI-based polymers in the first and second reduced states. Combined electrochemical, spectral and conductivity results show that the first reduced state is related to the formation of radical anions delocalised on NDI units, with formation of interchain π-stacks between adjacent reduced NDI units being probable. The second reduced state is related to the formation of spinless species, whose properties are modified to a greater extent by the donor units. These results indicate that n-doping of naphthyl diimide-based conjugated polymers is significantly different from the doping of typical p-type conjugated polymers, which entails the formation of delocalised charge carriers, such as polarons and bipolarons. The n-type (electron acceptor) performance of NDI-based polymers was practically verified by employing them, along with poly(3-hexylthiophene) electron donor, in bulk heterojunction photovoltaic devices.
A boron-doped unzipped carbon nanotubes/sulfur (BUCNTs/S-1) composite was first prepared via a one-pot facile hydrothermal process by using oxidized unzipped carbon nanotubes (O-UCNTs), boron acid and element sulfur as the carbon precursor, B and S sources, respectively. The morphology, structure and composition of the BUCNTs/S-1 composite were characterized and the effect of B doping and sulfur loading were also investigated in details. The results demonstrated that the participation of B atom and sulfur loading achieved by hydrothermal method endowed the BUCNTs host with enhanced conductivity, promoted sulfur dispersibility and strengthened adsorbability for the sulfur species. The electrochemical performances of the BUCNTs/S-1 used as lithium-sulfur cathodes were then studied. Benefitting from all the merits, the BUCNTs/S-1 cathode delivered a high initial capacity of ∼1251mAh/g at 0.2C, retaining as high as ∼750mAh/g after 400 cycles, displaying significantly enhanced cycling stability. Hence, this work provides a facile method to fabricate a promising sulfur cathode candidate for high performance lithium-sulfur batteries.
The 36 or 48V valve-regulated lead-acid (VRLA) battery packs have been widely applied to the power sources of electric bicycles or light electric scooters in China. The failure modes of the 12V/10Ah VRLA batteries have been studied by the cycle life test at C2 discharge rate and 100% depth of discharge (DOD). It indicates that the main cause of the battery failure in this cycle duty is the softening and shedding of positive active mass (PAM) rather than individual water loss, recombination efficiency or sulfation, etc. When the electrolyte saturation falls to a certain extent, the high oxygen recombination current leads to the depolarization of the negative plate and the shift of the positive plate to a higher potential. The violent oxygen evolution accelerates the softening of PAM and the end of cycle life.
Single-C formic acid-based metal-organic frameworks (MOFs) are used to construct novel ZnO@porous carbon matrix nanocomposites by controlled pyrolysis. In the constructed nanocomposites, the porous carbon matrices act as a confined support to prevent agglomeration of the ZnO nanoparticles and create a rapid electron conductive network. Meanwhile, the well-defined, continuous porous structured MOFs provide a large specific surface area, which increases the contact of electrolyte-electrode and improves the penetration of electrolyte. Especially, the reasonable choice of formic acid-based MOFs construct the low carbon content composite, which contribute to the high energy density and long cycle life. The constructed nanocomposites show stable, ultrahigh rate lithium ion storage properties of 650mAhg−1 at charge/discharge rate of 1C even after 200 cycles.
In this work, Co3O4 nanoparticles were loaded on the nitrogen-doped porous carbon spheres (NPCS) by a facile hydrothermal method. The NPCS were derived from carboxymethyl chitosan as the carbon and nitrogen source. The as-prepared Co3O4/NPCS nanocomposites were used as anode materials for lithium-ion batteries. The electrochemical results showed that the materials possessed a high initial discharge capacity of 1245.5mAhg−1 and still maintained a high reversible capacity of 983.9mAhg−1 after 100 cycles at a current density of 100mAg−1. Even at a high current density of 5Ag−1, it delivered a very stable reversible capacity of 659mAhg−1. The high electrochemical performance of the Co3O4/NPCS nanocomposites can be attributed to the synergistic effects of the nanoscale Co3O4 particles, the porous structure of the NPCS and the N functional groups on the NPCS.
Gas diffusion backings (GDBs) with various PTFE loadings for unitized regenerative polymer fuel cells (URFCs) were prepared and the relations between the PTFE loading amount and the URFC performance were examined. As for the GDB of the hydrogen electrode, both the fuel cell and water electrolysis performances were not affected by the amount of PTFE loading on the hydrogen side GDB. However, the URFC performances significantly depended on the PTFE loading amount of the GDB for the oxygen electrode; during the fuel cell and water electrolysis operations, URFC showed higher performances with smaller PTFE loadings but the cell with no PTFE-coated GDB showed a very deteriorated fuel cell performance. Cycle properties of the URFC revealed that the efficiency of the URFC decreased with the increasing cycles when the PTFE loading on oxygen side GDB was too low, however, a stable operation can be achieved with the appropriate PTFE loading on the GDB.
Lithium metal is an attractive anode material for rechargeable batteries, owing to its high theoretical specific capacity of 3,860 mAh g−1. Despite extensive research efforts, there are still many fundamental challenges in using lithium metal in lithium-ion batteries. Most notably, critical information such as its nucleation and growth behaviour remains elusive. Here we explore the nucleation pattern of lithium on various metal substrates and unravel a substrate-dependent growth phenomenon that enables selective deposition of lithium metal. With the aid of binary phase diagrams, we find that no nucleation barriers are present for metals exhibiting a definite solubility in lithium, whereas appreciable nucleation barriers exist for metals with negligible solubility. We thereafter design a nanocapsule structure for lithium metal anodes consisting of hollow carbon spheres with nanoparticle seeds inside. During deposition, the lithium metal is found to predominantly grow inside the hollow carbon spheres. Such selective deposition and stable encapsulation of lithium metal eliminate dendrite formation and enable improved cycling, even in corrosive alkyl carbonate electrolytes, with 98% coulombic efficiency for more than 300 cycles.
Crosslinkable sulfonated poly (diallyl-bisphenol ether ether ketone) (SDPEEK) membranes with different degrees of sulfonation (DS) are prepared and first investigated in vanadium redox flow battery (VFB) application. The SDPEEK membranes with DS of 80% (SD4-6-100) show over an order of magnitude lower permeability of VO2+ ions (2.4 × 10−8 vs. 1.04 × 10−6 cm2 min−1) than currently used Nafion 115. The VFB battery assembled with SD4-6-100 membrane exhibits much higher columbic efficiency (98% vs. 92% at 50 mA cm−2) and longer self-discharge time (180 h vs. 50 h) than that of Nafion 115, however, at similar energy efficiency. The membrane keeps a stable performance after 900 h charge–discharge test. In order to further improve the ions selectivity of SDPEEK membranes with high DS, the SD5-5-50 (DS 100%) membrane is crosslinked under ultraviolet (UV) radiation. The ion selectivity of the membrane is improved obviously after crosslinking, as a result, showing much higher columbic efficiency and energy efficiency.
Insular electricity grids are considered to have a more fragile structure than the mainland ones due to several factors such as the lower inertia because of lower number of generation facilities connected to the system, absence or insufficient interconnection with the main grid, etc. The recent trend of integrating large portions of environmentally sustainable power generation units that have a significantly volatile nature in the generation mix (such as wind and solar energy conversion systems) within this fragile structure, poses profound challenges that need deeper and specific analysis. This study aims to provide an overview of insular power system structures and operational requirements, especially under increasing penetration of renewable energy sources. Firstly, a general evaluation of insular power systems is presented. Then, potential challenges are thoroughly discussed together with opportunities to tackle them. Future technological developments, as well as innovative applications are also given special attention. Hence, this paper contributes to the scarce literature regarding insular power systems by providing a critical overview of issues regarding their operation and possible solutions.
Electrochemical performance of lithium ion batteries is associated with structural and chemical stability of electrode materials. In the case of nickel-rich layered cathode materials LiNi0.6Co0.2Mn0.2O2, cation mixing, which results from the migration of transition metal ions into vacant lithium sites, is accelerated owing to similar ionic radii between nickel and lithium. However, the inevitable lattice distortions and chemical evolution have not been investigated intensely. In this paper, we report the structural evolution localized at surface regions through electron diffraction and high resolution imaging analyses with aberration-corrected transmission electron microscopy and scanning transmission electron microscopy. Repetition of volumetric change generates cracks and voids associated with deterioration of electrochemical performance. Structural change is related with (003) intensity in electron diffraction and it can be presented by dark field transmission electron microscopy imaging at a glance. Drastic structural degradation during early cycling shows relation with rapid capacity and voltage fade. Electron energy loss spectroscopy elucidates that the structural evolution caused by the migration of Ni ions accompanies chemical modification of Mn ions and creation of hole states at the O2p level. This study provides an insight into correlating structural and chemical evolution with degradation mechanism on battery performances of LiNi0.6Co0.2Mn0.2O2 cathode materials.
Research into secondary recovery of rare earth elements (REE) has focused mostly on hard disk drives and automotive applications. While REE content in Japanese and European vehicles is relatively well-known, understanding of U.S. vehicles is mostly based on database analysis. An attempt to pinpoint which components contain the most REEs was conducted on four different vehicle models including the Ford F-150, Chevrolet Silverado, Toyota Corolla and Honda Accord. The disassembly data were combined with 2017 vehicles in operation to estimate stocks and flows of Neodymium-Iron-Boron (NdFeB). Results showed that U.S. vehicles had major differences compared to Japanese and European vehicles. NdFeB magnets were only found in speakers ranging from 16 to 114 g/vehicle. An estimated 3.0–14 tonnes of NdFeB could be available from end-of-life vehicles in 2018 from different cohorts of the four aforementioned models. While opportunities for recycling NdFeB in vehicles exist, challenges are also present.
Polyaniline (PAni) films with similar electroactivity were potentiodynamically grown at selected different scan rates and number of cycles. Palladium particles were incorporated in the electroactive polymer by electroless precipitation. The polymeric matrix morphology and its effect on the distribution and size of Pd particles was analysed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was observed that the dispersion of metal clusters was imparted by the nature of the polymer matrix. The results allowed to state a correlation between the polymer topography and the size and spatial distribution of the catalytic particles.
We report the structural and electronic characterization of Li2FeSiO4 synthesized by solid-state reaction. X-ray diffraction, Raman scattering, Fourier transform infrared (FTIR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy and magnetization measurements are analyzed. Magnetic susceptibility experiments give evidence that Li2FeSiO4 powders possess an antiferromagnetic ordering below T N =25K due to long range Fe–O–Li–O–Fe interactions. Analysis of the paramagnetic region giving the Curie–Weiss parameters θ p =−93.5K and C p =4.13emuKmol−1 shows the divalent state of Fe cations. Electron paramagnetic resonance experiments confirm this electronic configuration. Electrochemical measurements were carried out in lithium cells with LiTFSI in a poly(ethylene oxide) (PEO) polymer electrolyte at 80°C. The resulting cyclic voltammogram indicates a stable structure for the first cycle with redox peaks at 2.80 and 2.74V versus Li0/Li+.
There are many types of high-power batteries used in HEVs, and their durabilities and degradation mechanisms are different. In this paper, four types of commercial high-power batteries, including two types of LTO/NCM lithium-ion battery from two different manufacturers, a C/LMO battery and a supercapacitor (SC), are studied. A durability test with a realistic current profile for an HEV is used so that the durability results more closely reflect real operating conditions than a general cycle life test. Incremental capacity (IC) curves are used to qualitatively analyze the degradation mechanism. To compensate for defects in the IC method, a prognosis model, using a genetic algorithm to reconstruct constant current charge voltage curves, is adopted to quantitatively identify the battery aging mechanism.
Objectives We aimed to evaluate the efficacy of the selective H3 receptor inverse agonist MK-0249 to treat excessive daytime sleepiness (EDS). Methods In this three-period, double-blind, crossover study, 125 patients (100 men, 25 women; mean age, 48.6years) with obstructive sleep apnea receiving nasal continuous positive airway pressure therapy who had refractory EDS were randomized to 2weeks each of daily MK-0249 (5, 8, 10, or 12mg, adaptively assigned), modafinil 200mg, and placebo. At baseline and after each treatment period, six maintenance of wakefulness tests (MWT) and Psychomotor Vigilance Tasks (PVT) were conducted at 2-h intervals, beginning 1h postdose (∼09:00). The Epworth sleepiness scale (ESS), Clinical Global Impression of Severity (CGIS) and Digit Symbol Substitution Test (DSST) also were assessed. The primary end point was MWT sleep latency averaged over the first four time points (MWT-early). Results MWT-early mean change from baseline sleep latency at week 2 was 1.2min for placebo, 2.1min for MK-0249 (top two doses pooled; P >.05 vs placebo), and 5.9min for modafinil (P ⩽.001 vs placebo). MK-0249 showed improvements vs placebo on secondary and exploratory end points of ESS, CGIS, PVT, and DSST. Insomnia adverse events (AEs) were greater for MK-0249 (combined doses, 17.5%) than for placebo (0.9%) or modafinil (1.8%). Conclusion MK-0249 did not significantly affect MWT sleep latency. However, the pattern of improvement on subjective ratings and psychomotor performance end points suggested that MK-0249 was associated with changes in aspects of cognition and performance not captured by the MWT.
Although reperfusion injury has been shown to be responsible for cardiomyocytes death after an acute myocardial infarction, there is currently no drug on the market that reduces this type of injury. TRO40303 is a new cardioprotective compound that was shown to inhibit the opening of the mitochondrial permeability transition pore and reduce infarct size after ischemia-reperfusion in a rat model of cardiac ischemia-reperfusion injury.
Over the last few decades, lithium-ion (Li-ion) batteries have attracted significant attention due to their high energy density, low maintenance, and the variety of shapes, chemistries and performances available. Meanwhile, reliability and safety assessment of Li-ion batteries has become an important issue for original equipment manufacturers, in particular for future electric vehicles’ performance. Evaluation of reliability and safety plays an important role to assess overall Li-ion battery behavior over its lifespan. This paper presents the role, mechanism and outcome of the different failures for evaluating reliability and safety of Li-ion batteries in electric vehicles. Additionally, the contribution of Li-ion battery degradation in five main failure modes and capacity and power fade for providing reliability assessment models as solutions of existing challenges have been investigated.
Low back pain (LBP) is common among healthcare workers, whose work is physically strenuous and thus demands certain levels of physical fitness and spinal control. Exercise is the most frequently recommended treatment for LBP. However, exercise interventions targeted at sub-acute or recurrent patients are scarce compared to those targeted at chronic LBP patients. Our objective was to examine the effects of 6 months of neuromuscular exercise on pain, lumbar movement control, fitness, and work-related factors at 6- and 12-months’ follow-up among female healthcare personnel with sub-acute or recurrent low back pain (LBP) and physically demanding work.
In the present work, our attention has been focused on the desired prevention of irreversible sulphation of negative test electrodes during cycling under simulated high-rate HEV duty. To this end, the negative active material was doped with carbon and, for comparison, with titanium dioxide as a nonconducting powdered additive, and the negative as well as positive electrodes were subjected to a defined pressure. Accelerated cycling revealed that electrodes doped with carbon in laboratory VRLA cells perform, in the first run, better than those doped with TiO2 since they reached about 30,000 cycles regardless of the applied pressure. However, the electrode performances were almost equalized in the second run. Mechanical pressure of 4Ncm−2 has a pronounced favourable effect on the cycle life of negative electrodes with expanders. Higher pressures are not recommended. Electrodes doped with carbon but without standard expanders are capable of long-life cycling at elevated pressures around 6Ncm−2. Their cycle life is comparable to that of the electrodes with expanders.
A new systematic approach to state of charge (SoC) observer design for battery cells is presented. It is based on a purely data driven model and a nonlinear observer constructed from it. As a key novelty, a unified and generic framework for model generation (i.e. design of experiments, nonlinear model structure) and observer parametrisation is presented. An integral part of SoC observers in hybrid electrical vehicles is a dynamic battery model which describes the nonlinear system behaviour of the cell terminal voltage. In order to enable the application of the proposed concepts for any type of battery chemistry, a data based modelling approach using the architecture of local model networks (LMNs) is proposed. As an important prerequisite, optimal model based experiment design ensures proper excitation of the system dynamics while the desired SoC operating range is covered. For SoC estimation, an augmented state space representation of the LMN is derived and the nonlinear observer design is presented. In particular, the use of a fuzzy observer is beneficial in combination with LMNs since the local observers are time-invariant which greatly reduces the complexity of the global estimator. The proposed concepts are validated experimentally by means of a Lithium Ion power cell.