batterydata/paper-abstracts huggingface dataset:
Co-doped LiFe1−x Co x PO4/C (x =0, 0.005, 0.010, 0.020) composites were synthesized by oxalic acid-assisted sol–gel method and their electrochemical properties had been investigated in detail using galvanostatic charge/discharge, cyclic voltammograms (CVs) and electrochemical impedance spectra (EIS) tests. Co-doping benefited the transportation of Li+ and electrochemical conductivity which lead to the excellent high rate capability. The doped LiFe1−x Co x PO4/C with x =0.010 exhibited the best electrochemical properties, with discharge capacity of 114.8 and 104.2mAhg−1 at 10C and 20C, respectively.
The effect of moisture content on the electrochemical performance of a LiNi1/3Co1/3Mn1/3O2 (NCM)/graphite battery was investigated by studying different moisture contents of a positive-NCM/Li half cell, negative-graphite/Li half cell and positive-NCM/negative-graphite cell. The moisture content influences the oxidized decomposition of electrolyte. A higher moisture content results in a lower oxidized decomposition potential. The product of oxidized decomposition deposits on the surface of positive, and results in an increase of positive resistance (R f). The NCM structure is stable with change in moisture content. Moisture joined in the formation reaction and changed the components of the solid electrolyte interphase film in negative. The high moisture content resulted in a thick, porous, non-dense solid electrolyte interphase film. Cycle testing of the NCM/graphite cell shows that a moisture content in the negative electrode influences capacity fading more significantly than in the positive electrode. The reason for capacity fading was studied by three-electrode technology. The increase in negative impedance is the main reason for an increase in battery impedance. The battery impedance increased rapidly when the moisture content in the negative electrode was high. This resulted in accelerated capacity fade.
Poly(acrylic acid) (PAA) is widely used as a polymer binder for high capacity silicon (Si) anodes in Li-ion batteries. When used, the carboxyl (CO2H) groups of PAA can be partially lithiated (known as pre-lithiation treatment), which is believed to facilitates lamination process, especially for production on a large scale. However, such treatment impacts numerous physico-chemical properties of the PAA binder that affect the cycling performance of the electrode. Here we seek to quantify the pre-lithiation treatment effect on Li-ion cells containing Si-graphite composite electrodes. The electrochemical cycling results indicated that such pre-lithiation treatment of PAA can undermine the cycling performance, as more capacity loss was observed when pre-lithitated PAA binders were used. On the other hand, the same pre-lithiation practice is indeed beneficial for the lamination process, as it increases the viscosity of aqueous slurries at low shear rates (slows down sedimentation) and prompts the shear thinning (so that the slurries can be more easily mixed). Thus, there is an uneasy balance between the electrochemical performance that suffers from the pre-lithiation of PAA and the quality of slurry processing which benefits from the same practice. An alternative approach to slurry treatment would be desired to achieve better cycling performance without undermining the stability of slurry suspensions.
We focus on the charging process of a fleet of electric vehicles overnight for providing load-side regulation service. At the heart of this complex problem, the goal is to transfer a certain amount of energy to the fleet by a given deadline; however, when and how fast the energy is sent is flexible. We examine a unidirectional setting in the cases where regulation signals are deterministic (worst case) and stochastic. We study both a single-shot optimization scenario carried at the start of the charging period, and a dynamic optimization scenario, where the optimal control strategy is re-evaluated several times over the duration of the charging interval. We show that most of the gains from dynamic optimization can be obtained by re-evaluating the optimization problem at the midpoint of the charging interval. Moreover, the optimal value of the regulation service in the worst-case deterministic setting nearly matches the stochastic setting with dynamic optimization. We validate our results using both simulation and real-world data.
Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity. One of the main challenges within cyber foraging is that it is very difficult to develop cyber foraging enabled applications. An application using cyber foraging is working with mobile, distributed and, possibly, parallel computing; fields within computer science notoriously hard for programmers to grasp. This paper presents Scavenger—a cyber foraging system supporting easy development of mobile cyber foraging applications, while still delivering efficient, mobile use of remote computing resources through the use of a custom built mobile code execution environment and a new adaptive, dual-profiling scheduler.
In this paper, the thermal runaway features of a 25 Ah large format prismatic lithium ion battery with Li(Ni x Co y Mn z )O2 (NCM) cathode are evaluated using the extended volume-accelerating rate calorimetry (EV-ARC). 4 thermocouples are set at different positions of the battery. The temperature inside the battery is 870 °C or so, much higher than that outside the battery. The temperature difference is calculated from the recorded data. The temperature difference within the battery stays lower than 1 °C for 97% of the test period, while it rises to its highest, approximately 520 °C, when thermal runaway happens. The voltage of the battery is also measured during the test. It takes 15–40 s from the sharp drop of voltage to the instantaneous rise of temperature. Such a time interval is beneficial for early warning of the thermal runaway. Using a pulse charge/discharge profile, the internal resistance is derived from the quotient of the pulse voltage and the current during the ARC test. The internal resistance of the battery increases slowly from 20 mΩ to 60 mΩ before thermal runaway, while it rises to 370 mΩ when thermal runaway happens indicating the loss of the integrity of the separator or the battery swell.
Simplified battery models provide a good trade-off between accuracy and efficiency and are crucial for the implementation in battery management systems for the prediction of the batteries’ electrical and thermal performance. The coupling between a thermal and an electrical model considers the heat generation and the temperature dependent behavior of the cell. However, the measurements for parametrization of such battery models are currently time consuming and complex. This work introduces a method for extracting the entropic heat coefficient as well as the electrical parameters from the same pulse relaxation measurements which saves plenty of time and effort. The pulse relaxation method is applied at four different temperatures and three different current rates to a LiCoO 2 cell from LG Chem with 2.15 Ah. A subsequent least squares estimation between the measured and the simulated temperature profiles refines the extracted entropic coefficient. The comparison between the determined coefficients and the coefficients measured by the well-established procedure shows a good agreement. The simulated and measured surface temperature corresponds well and therefore validates the electro-thermal model with the determined parameters. The maximum temperature deviation between the simulation and the measurement takes 0.5 K at an ambient temperature of 15 ∘ C and applied current pulses of I = 1.29 A .
Compact neutron detectors are being designed and tested for use as low-power real-time personnel dosimeters. The neutron detectors are pin diodes that are mass produced from high-purity Si wafers. Each detector has thousands of circular perforations etched vertically into the device. The perforations are backfilled with 6LiF to make the pin diodes sensitive to thermal neutrons. The prototype devices deliver 4.7% thermal neutron detection efficiency while operating on only 15V, showing a 9% increase in efficiency over identical planar devices.
Mastery over the structures at nano/microscale can effectively tailor the catalytic activity and durability of materials. Herein, three dimension (3D) hierarchical iron diselenide (FeSe2) microspheres have been successfully synthesized via a hot-injection method. The morphologies of building blocks and final products can be simply controlled by the amount and/or the type of alkythiols, from irregular micro/nanoparticles to uniform 3D hierarchical microspheres made of ultrathin nanosheets or rhombus-like nanorods. A formation mechanism has been understood based on the inherent crystal structure of FeSe2 and the selective adsorption of alkythiols. The as-obtained FeSe2 samples were employed as counter electrode (CE) materials in dye-sensitized solar cells (DSSCs). Electrochemical characterizations indicated that the 3D hierarchical FeSe2 microspheres composed of ultrathin nanosheets (FeSe2 NSs) exhibited low charge transfer resistance at the electrolyte–electrode interface, high electrocatalytic activity and fast reaction kinetics for the I−/I3 − redox reaction. A DSSC with FeSe2 NSs CE achieved a high power conversion efficiency of 8.39% under a simulated solar illumination of 100mWcm−2 (AM 1.5), comparable to that of Pt based devices (8.20%). Moreover, the fast activity onset and relatively long stability demonstrated that the FeSe2 NSs is a promising alternative to Pt in DSSC.
Molybdenum oxide (MoO3) thin films have been obtained by plasma-enhanced atomic layer deposition using precursors of Mo(CO)6 and O2 plasma at a reactor temperature of 160 °C. The MoO3 thin films deposited on p-type silicon substrates with thermally grown 300 nm thick SiO2 layer with different numbers of ALD growth cycles. Spectroscopic ellipsometer is used to characterize as-grown film thickness and refractive index. The as-grown films are treated at annealing temperatures at 300–600 °C. The structural properties of as-grown and annealed thin films have been characterized by optical microscopy, µRaman spectra, and atomic force microscopy.
Water is in short supply with countries vying for access to river heads. Hong Kong (HK) is no different. It relies on supply from Mainland China with other cities rivalling access. Yet there is still no great impetus for water conservation. This paper reports on progress in setting up a pilot biological wastewater treatment plant and a PV-powered UV-LED disinfection system plus a feasibility study carried out in conjunction with a local developer investigating the application of the treated water for irrigation. The objective is to incorporate the systems within a small-scale community for its contribution to water and energy conservation as well as establish the parameters for replication in other countries with potential up-scaling for urban application.
At present, no satisfactory reports on the monitoring of cerebral function to predict functional outcomes after brain damage such as traumatic brain injury (TBI) and stroke. The middle latency auditory-evoked potential index (MLAEPi) monitor (aepEX plus®, Audiomex, UK) is a mobile MLAEP monitor measuring the degree of consciousness that is represented by numerical values. Hence, we hypothesized that MLAEPi predicts neurological outcome after emergency craniotomy among patients with disturbance of consciousness (DOC), which was caused by brain damage.
Zn–Al–La–CO3 layered double hydroxides (LDHs) are prepared by the constant pH co-precipitation method and proposed as a novel anodic material in Zinc–Nickel secondary cells. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images reveal that the as-prepared samples are well-crystallized and hexagon layer structure. Electrochemical performances of Zn–Al–La-hydrotalcites with different Zn/Al/La molar ratios are investigated by galvanostatic charge–discharge measurements, cyclic voltammograms (CV) and Tafel polarization curves. In comparison with the Zn–Al-hydrotalcite, Zn–Al–La-hydrotalcites with different Zn/Al/La molar ratios have more stable cycling performance. After 400 cell cycles, Zn–Al–La-LDH with Zn/Al/La = 3:0.8:0.2 retains specific discharge capacity of 297 mAh g−1 with a retention rate of 79.0%, which is much superior to that of 205 mAh g−1 with a retention rate of 53.5% for the Zn–Al–La-LDH with Zn/Al/La = 3:0.9:0.1 and 241 mAh g−1 with a retention rate of 69.0% for the Zn–Al–La-LDH with Zn/Al/La = 3:0.6:0.4. The results demonstrate that the Zn–Al–La-LDH with Zn/Al/La = 3:0.8:0.2 has the best reversible cycling behavior. The CV exhibits well reversibility and the Tafel polarization curves reveal more positive corrosion potential for Zn–Al–La-hydrotalcite.
Lithium vanadium fluorophosphate, LiVPO4F is prepared by two-step carbothermal reduction method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), density and surface area. Its cathodic behaviour is examined by galvanostatic charge–discharge cycling up to 1260 cycles, cyclic voltammetry (CV) and impedance spectra using Li-metal as the counter and reference electrode. When cycled between 3.0 and 4.5V at 15mAg−1 (0.12C), a reversible and stable capacity of 130 (±3)mAhg−1 is observed in the range 20–200 cycles. Slow capacity fading occurs between 200 and 360 cycles. When cycled at the 0.92C rate (1C =130mAg−1), a reversible and stable capacity of 122 (±3)mAhg−1 is obtained at 200–800 cycles. The capacity degrades slowly over 800–1260 cycles and the total loss is ∼14%. Coulombic efficiency increases to 96–98% after the first 10–15 cycles. The CV data show that the charge–discharge process, a two-phase reaction, occurs between 4.2 and 4.5V, in agreement with literature data. Impedance spectra, up to 90 cycles are fitted to an equivalent circuit and the variation of impedance parameters is interpreted.
Amorphous films deposited by pulsed laser deposition from a crystalline Li2PO2N target in a N2 ambient atmosphere (LiPON-PLD) have been examined as an approach to reduce the charge-transfer resistance at the electrode-solid electrolyte interface. Despite the relatively low ionic conductivity of ca. 1.5 × 10−8 S cm−1 at 25 °C, the amorphous LiPON-PLD films deposited between a LiMn1.485Ni0.45Cr0.05O4 (LNM) cathode and LiPON electrolyte resulted in sharply improved electrochemical performance in terms of charge-transfer resistance and CV profiles. Cells without a LiPON-PLD film had a charge-transfer resistance of 4470 Ω-cm2 compared to 760 and 960 Ω-cm2 for the sample with 17 nm and 31 nm thick LiPON-PLD films, respectively. The LiPON-PLD amorphous films show no evidence of the continuous planar PNPN- backbone characteristic of the crystalline target material, but compared with LiPON prepared from radio frequency magnetron sputtering with Li3PO4 in a N2 atmosphere, the LiPON-PLD films were composed of a higher amount of triply coordinated P − N < P P with relatively lower contributions of PNP.
This paper reports the synthesis of highly loaded SnO2/mesoporous carbon (MC) nanohybrid through a facile chemical solution process and subsequent annealing methodology, by using a novel three-dimensional (3D) MC as a buffering and conducting matrix. Owing to its unique structural characteristics, the MC–SnO2 nanohybrid anode exhibits markedly improved cycling stability and rate capability compared to pure SnO2 nanoparticles, facilitating its application in advanced Li-ion batteries (LIBs) with long cycle life and high power density.
The aging process clearly increases the demand for antioxidant protection, especially in the brain, involving that provided by α-tocopherol (αT). However, little is known about the age-related changes in brain αT levels and the influencing effect of gender on it, in human or murine samples as well. Accordingly, the aim of the current study was to detect age-, gender- and region-specific changes in αT concentrations in mouse brain tissue and to assess the influencing effect of plasma αT levels on it. Female and male C57BL/6 mice at the ages of 6, 16 and 66 weeks (n = 9 in each group) were applied. αT levels were determined with high performance liquid chromatography (HPLC) from the striatum, cortex, hippocampus, cerebellum, brainstem and from plasma samples. A detailed validation process was carried out for the applied HPLC method as well. The results demonstrated that brain αT levels significantly increased in the striatum, cortex, and hippocampus with aging in both genders, but in a more pronounced way in females with an increasing magnitude of this difference. In case of the cerebellum, a moderate elevation could be detected only in females, whereas in case of the brainstem there was no significant change in αT level. With regard to plasma samples, no clear trend could be identified. The current study is the first to present age-dependent gender-specific changes in αT level in certain brain regions of the C57Bl/6 mouse strain, and may provide meaningful information for future therapeutic studies targeting aging-related processes.
The electrochemical properties of bare and Co3(PO4)2-coated LiNi0.8Co0.16Al0.04O2 electrodes after high current damage testing were characterized. Damage was induced by cycling with a high current density of 600 m Ag−1. Co3(PO4)2-coated LiNi0.8Co0.16Al0.04O2 electrodes exhibit lower capacity loss and better charge retention than bare LiNi0.8Co0.16Al0.04O2 electrodes after damage testing. The discharge capacity reduction of bare and Co3(PO4)2-coated electrodes after damage testing were ∼27 and 15%, respectively. The impedance of cells containing bare electrodes remarkably increased after high current cycling, which may be induced by damage to the electrode surface. However, damage was successfully suppressed by the Co3(PO4)2 coating. Bare LiNi0.8Co0.16Al0.04O2 electrodes developed large amounts of cracks and other extended defects after high current cycling. In contrast, Co3(PO4)2-coated electrodes maintained stable features after high current cycling, indicating the coating layer effectively protected the surface of the LiNi0.8Co0.16Al0.04O2 powder.
Aiming at a molecular scale understanding of the cathode processes in an Mg-air battery, we have investigated the oxygen reduction (ORR) and oxygen evolution (OER) reactions under well-defined conditions, using an ionic liquid (butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide, [BMP][TFSA]) based electrolyte and polycrystalline Au and glassy carbon, respectively, as model electrodes. Electrochemical measurements performed under enforced electrolyte flow provide information on the electrochemical and electrocatalytic properties of these electrodes, in particular on the reversibility of the ORR/OER both in the absence and in the presence of Mg2+ in the electrolyte, and on the build-up of a reaction inhibiting passivation layer (solid-electrolyte interphase). Further information on the nature of the deposits and their dependence both on the electrode material and on the potential cycling conditions is derived from scanning electron microscopy/energy dispersive X-ray spectroscopy and from X-ray photoelectron spectroscopy measurements performed ex situ after the electrochemical measurements. Consequences of these results on the understanding of the ORR/OER under these conditions and in particular of the nature and role of the solid-electrolyte interphase layer formed during potential cycling and their relevance for the operation of Mg-air batteries are discussed.
Zn/MnO2 batteries including an ionic liquid-based gel polymer electrolyte (IL-GPE) have been discharged or discharged and then recharged reaching different states of charge. The Zn electrodes used in these Zn/MnO2 batteries are studied by HAXPES and synchrotron XRD techniques. Besides, HAXPES measurements are compared with the results obtained by a conventional XPS. Formation of Zn(OH)2 and ZnO is found in intermediate states of charge during charging and discharging. However, only ZnO is observed in the anode when a full discharging was carried out. Conversely, an entire charging process produces a complete reduction of all Zn2+ species to metallic Zn. In addition, various techniques have confirmed the entrance of Triflate anions and NMP solvent molecules in the electrode, accompanying the Zn2+ cations movement during the charging.
Two new monomers, 2-benzyl-5,12-dihydro-2H-pyrrolo[3′,4′:2,3][1,4]dioxocino[6,7-b]quinoxaline (DPOQ) and 5,12-dihydrothieno[3′,4′:2,3][1,4]dithiocino[6,7-b]quinoxaline (DTTQ), were synthesized. The chemical structures of the monomers were characterized by nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR) and mass spectra. Copolymer of DPOQ with bithiophene (BT) was synthesized via potentiostatic electrochemical polymerization in acetonitrile–tetrabutylammonium tetrafluoroborate solvent–electrolyte couple. For DTTQ, copolymerization with bithiophene was achieved via potentiodynamic method in dichloromethane–tetrabutylammonium hexafluorophosphate solvent–electrolyte couple. Characterizations of the resulting copolymers were performed by cyclic voltammetry (CV), FTIR, scanning electron microscopy (SEM) and UV–Vis spectroscopy. Four-probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the copolymer films were investigated. In addition, dual type polymer electrochromic devices based on P(DPOQ-co-BT) and P(DTTQ-co-BT) with poly(3,4-ethylenedioxythiophene) were constructed. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts and optical memories.
Cognitive deficits predict functioning in schizophrenia; however, little is known as to whether the association is present in other mental disorders. If specific cognitive deficits uniquely predict functional impairment in schizophrenia the association of select aspects of brain dysfunction with daily living would suggest an intervention target and perhaps a means by which to improve the functioning of schizophrenia patients. The relationship of cognition and functioning was investigated in schizophrenia (n =39), bipolar affective disorder (n =27), and nonpsychiatric control (n =38) participants to determine whether the associations varied across groups. We examined verbal memory, verbal learning, verbal fluency, vigilance, executive functioning, symptomatology, and generalized cognitive functioning for associations with social function. Correlational analyses revealed particular cognitive domains (e.g., verbal memory) to be associated with social functioning in schizophrenia, bipolar, and control subjects; however generalized cognitive function and symptomatology were also associated with social functioning in patients. Multiple regression analyses revealed that in schizophrenia poor verbal memory predicted worse social functioning even after the effects of generalized cognitive dysfunction were considered. Verbal memory indices failed to account for variance in social function in bipolar patients and control subjects after consideration of generalized cognitive function. Bipolar patients with worse planning and problem solving tended to have worse social functioning. Therefore, unlike schizophrenia patients who may fail to process verbally mediated material, bipolar patients' difficulty with logical approaches to problems in daily living may have the greatest impact on their community function.