batterydata/paper-abstracts huggingface dataset:
Modern electronic systems are smarter and compact, yet highly efficient at greater speeds. These systems require just a minimal amount of power which have indeed encouraged new technologies to scavenge energy from the surrounding environment. Triboelectric nanogenerator (TENG) is one such device which has demonstrated a cost-effective, reliable and efficient technology for harvesting natural mechanical energy. However, the durability and stability of TENG is a critical attribute for the high output efficiency at a consistent rate and strongly depends on the frictional characteristics of triboelectric materials. In the first of its kind, a detailed investigation is done on the ability of diamond-like carbon (DLC) film to be a potential triboelectric material for TENG applications. DLC film was deposited on the substrate (electrode) of a contact-separation based TENG (CS-TENG) using plasma-based ion implantation and deposition (PBII&D) technique. The performance evaluation of TENG consisting of DLC film - polymer as the triboelectric pairs revealed some very interesting results. Hydrogenated DLC (H-DLC) and PTFE (Polytetrafluoroethylene) based TENG produced the highest output with a peak current of 3.5 μA and a power density of up to 57 mW/m2 over other conventional dielectric pairs like Al-PTFE, Polyimide (Kapton®)-PTFE, and Kapton-Al. Furthermore, fluorine doped DLC (F-DLC) film produced a moderate output with Kapton, and PTFE, indicating its benefits for TENG applications. In the durability assessment, the DLC deposited rotary sliding-TENG exhibited excellent durability by producing a stable output current for 3 h at a reduced friction coefficient. This study serves as a noteworthy beginning towards the understanding of the triboelectric behavior of DLC films from TENGs perspective and could significantly contribute to designing of a highly durable, cost-effective, low friction and efficient sliding-TENG.
Polyaniline (PANI)/polysulfone (PSF) composite films with asymmetric porous structure were successfully prepared by electropolymerization. The back face (in contact with the electrode) of the freestanding composite film is green while the outer face is white. The chemical component and the morphology of the surfaces were characterized by FTIR spectra and scanning electron microscopy, respectively. It was shown that replicate films gave reproducible voltammetry in 0.5M H2SO4. The influence of the electrolyte and the acidic concentration on the redox peak currents of polyaniline were investigated in detail. The composite film electrode showed good electrocatalytic activity for ascorbic acid, which the anodic overpotential was evidently reduced compared with that obtained at bare Pt electrode. The diffusion coefficient of ascorbic acid was 1.38×10−6 cm2 s−1.
A fuel cell is a promising energy conversion system that will eventually become the first-choice for producing power because of its clean or zero-emission nature. A steady-state, two-dimensional mathematical model with pressure and phase change effects for a single PEM fuel cell was developed to illustrate the inlet humidification and pressure effects on proton exchange membrane (PEM) fuel cell performance. This model considers the transport of species along the channel as well as water transfer through the membrane. It can be used to predict trends of the following parameters along the fuel cell channels: mole number of liquid water and water vapor, pressure, temperature, density, viscosity, velocity, saturation pressure, pressure drop, vapor mole fraction, volume flow rate, required pumping power and current density.
Highly ordered porous Cu2O film is electrodeposited on copper foil through a self-assembled polystyrene sphere template. Compared with the dense Cu2O film and the octahedral Cu2O powder, the ordered porous Cu2O film exhibits an improved electrochemical cycling stability. The capacity of the porous Cu2O film can maintain 336mAhg−1 and 213mAhg−1 after 50 cycles at the rate of 0.1C and 5C, respectively. The reversible capacity holds 63.4% as the discharge–charge rate even increases by 50 times. The enhanced high rate properties of the ordered porous film should be attributed to the sufficient contact surface of Cu2O/electrolyte and the short diffusion length of Li+. Moreover, the direct contact between Cu2O and current collector and the decreasing inactive interfaces of Cu2O/polymer binder are also suggested as being responsible for the enhanced high rate property.
Lithium metal anodes covered by a thin (6–10 Å) solid electrolyte interphase (SEI) film at its initial nucleation stage modeled as a single component (Li2O, LiF, Li2SO4, and Li3N) are examined with density functional theory and ab initio molecular dynamics simulations. The combined metal anode/SEI surfaces are exposed to an electrolyte containing salt, solvent, and lithium polysulfides. The polysulfide species are found to be easily reduced by the metal slab, even in the presence of the model SEI films. Although the chemical nature of the film and geometry of the exposed facet induces different decomposition kinetics, the reaction mechanisms are shown to be similar for the various SEI models, and end with the formation of Li2S on the surface of the anode or inside the SEI film. The density of states of the films at this nascent stage of SEI formation in contact with the Li metal surface are very different than those of the bulk crystals, usually showing new intermediate states between the metal and conduction bands, which suggests a change to an electronically conductive character that favors continuous reactivity.
Biopolymer-based materials have particular interest and they are alternatives to synthetic polymers based on the decreasing oil resources. In this report they may be viewed as innovative materials for optics area. The incorporation of Eu3+ into natural macromolecules hosts with purpose of producing highly efficient emitting phosphors is of widespread interest in materials science, due to their important roles in display devices. This paper describes studies of the DNA and europium triflate luminescent membranes and its potential technological applications are expanded to electroluminescent devices. The most conductive sample of DNA50Eu, exhibited an ionic conductivity equal to 1.02×10−4 Scm−1 and 1.55×10−3 Scm−1 at 25°C and 90°C, respectively. Techniques like DSC, XRD and POM, demonstrated that the inclusion of the guest salt does not change significantly the amorphous nature morphology of the samples. Moreover, the overall redox stability of 2.0V was an indication that this material has an acceptable stability window for an application in a solid state electrochemical devices.
Information about the cobalt electrodeposition mechanism at different pH values was obtained using an electrochemistry quartz crystal microbalance (EQCM) technique as well as potentiodynamic and potentiostatic techniques. Potentiodynamic and potentiostatic electrodeposition of ionic cobalt at pH 5.40 occurs via a direct reduction mechanism. The mass/charge relation was found to be 33.00gmol−1. At pH 2.70, electrodeposition under potentiodynamic conditions occurs via a mechanism of cobalt reduction with the formation of adsorbed hydrogen. Potentiostatic analysis verified that cobalt reduction occurs simultaneously via direct reduction and with the formation of adsorbed hydrogen. The ratio mass/charge (M/z) is 13.00gmol−1 for potentiodynamic conditions and 26.00gmol−1 for potentiostatic conditions and potentiodynamic conditions. The cobalt electrodissolution occurs directly to Co2+ in pH 2.7 and through of the intermediary Co+ that is oxidized to Co2+ in pH 5.4.
LiMnPO4/C samples synthesized by two different methods are characterized by physical and electrochemical measurements and the importance of porosity on the electrochemical activity is investigated. The LiMnPO4/C synthesized by solid-state route has porous micro-aggregates while the micro-aggregates of the LiMnPO4/C synthesized by wet-chemistry route are dense. The difference in porosity of the two samples leads to a significantly different electrochemical activity. When cycled at the rate of 0.1C, the sample synthesized by solid-state route can deliver a capacity of 121mAhg−1, while the sample synthesized by wet-chemistry route can only deliver a capacity of 36mAhg−1. Our result demonstrates that the formation of sufficient pores in the aggregates is essential to achieve high electrochemical activity for LiMnPO4 based material.
Two vanadium redox flow battery topologies have been compared. In the conventional series stack, bipolar plates connect cells electrically in series and hydraulically in parallel. The alternative topology consists of cells connected in parallel inside stacks by means of monopolar plates in order to reduce shunt currents along channels and manifolds. Channelled and flat current collectors interposed between cells were considered in both topologies. In order to compute the stack losses, an equivalent circuit model of a VRFB cell was built from a 2D FEM multiphysics numerical model based on Comsol®, accounting for coupled electrical, electrochemical, and charge and mass transport phenomena. Shunt currents were computed inside the cells with 3D FEM models and in the piping and manifolds by means of equivalent circuits solved with Matlab®. Hydraulic losses were computed with analytical models in piping and manifolds and with 3D numerical analyses based on ANSYS Fluent® in the cell porous electrodes. Total losses in the alternative topology resulted one order of magnitude lower than in an equivalent conventional battery. The alternative topology with channelled current collectors exhibits the lowest shunt currents and hydraulic losses, with round-trip efficiency higher by about 10%, as compared to the conventional topology.
Ternary oxides with general formula MMoO4 (where M is a 3d-transitional metal) were characterized as cathode materials for lithium rechargeable batteries by galvanostatic charge–discharge technique and cyclic voltammetry. The significant capacity fading after the first cycle of lithium insertion/removal takes place for different copper molybdates (α-CuMoO4 and high-pressure modification CuMoO4-III) corresponding to the irreversible copper reduction and formation of Li2MoO4 during the first discharge. X-ray powder diffraction data reveal the decomposition of pristine ZnMoO4 by electrochemical reaction, lithium zinc oxide with the NaCl-type structure and Li2MoO3 seem to be formed. Lithium intercalation into nickel and iron molybdates is shown to proceed without phase transitions, but at unsatisfactory low operating voltages.
In this study, a facile one-pot hydrothermal route has been employed for the preparation of Cu3SbS4 nanoplates and its use as an electrode material for supercapacitors has been demonstrated. The physico-chemical characterizations such as X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscope, and laser Raman spectroscopic studies revealed the formation of Cu3SbS4 with plate-like structures. The electrochemical properties of the Cu3SbS4 electrodes was studied using cyclic voltammetry (CV), galvanostatic charge-discharge (CD) and electrochemical impedance spectroscopy (EIS) analyses. The CV analysis indicated the presence of a pair of redox peaks suggesting the pseudocapacitive nature of the Cu3SbS4 electrode with a high specific capacitance of 60 F g−1 (obtained at a scan rate of 5 mV s−1). The Cu3SbS4 electrode possess a specific capacitance of about 41.78 F g−1 obtained from the CD profiles recorded using an applied current of 0.25 mA. The Cu3SbS4 electrode possess a high energy of about 11.375 Wh kg−1 and power density of 175 W kg−1 with excellent cyclic stability over 2500 cycles. The collective findings of this work suggested that the use of Cu3SbS4 nanoplates as an advanced electrode for supercapacitor applications.
The dynamics of human pigmentation in response to ultraviolet radiation (UVR) remain poorly characterized. In part, this is attributable to methodological issues relating to the overlap in spectra of hemoglobin and melanin. We describe a new method, based on the recording of reflectance properties following iontophoresis of a potent vasoconstrictor, noradrenaline. This removes the influence of blood, allowing measurement of pigmentation, represented as L* on the L*a*b* scale. Blood flow was separately assessed using laser Doppler flowmetry. We show that there is a clear dose response with the dose of UVR administered, that pigmentation peaks at 1 wk and declines over the following 10 wk, but does not return to baseline within this period. We show clear differences in the degree, but not the temporal pattern of pigmentation between different pigmentary groups. We also report that the relation between facultative pigment and constitutive pigment is incomplete, with a wide scatter of responses for the development of pigmentation irrespective of constitutive levels. For comparison we also document overall photoadaptation and relate changes in pigmentation to the overall changes in photoadaptation.
Gravity Recovery and Climate Experiment (GRACE) derived groundwater storage (GWS) data are compared with in-situ groundwater levels from five groundwater basins in Jordan, using newly gridded GRACE GRCTellus land data. It is shown that (1) the time series for GRACE-derived GWS data and in-situ groundwater-level measurements can be correlated, with R2 from 0.55 to 0.74, (2) the correlation can be widely ascribed to the seasonal and trend component, since the detrended and deseasonalized time series show no significant correlation for most cases, implying that anomalous signals that deviate from the trend or seasonal behaviour are overlaid by noise, (3) estimates for water losses in Jordan based on the trend of GRACE data from 2003 to 2013 could be up to four times higher than previously assumed using estimated recharge and abstraction rates, and (4) a significant time-lagged cross correlation of the monthly changes in GRACE-derived groundwater storage and precipitation data was found, suggesting that the conventional method for deriving GWS from GRACE data probably does not account for the typical conditions in the study basins. Furthermore, a new method for deriving plausible specific yields from GRACE data and groundwater levels is demonstrated.
Thermal stabilities of a series of blended LiMn2O4 (LMO)–LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25 °C–580 °C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250 °C. Formation of MnO with rock-salt structure started at 520 °C. This observation is in contrast to the previous report for chemically delithiated LMO in air, in which a process of λ-MnO2 transforming to β-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumption by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.
MoS2 is a promising anode material due to its graphite-like structure and high theoretical capacity (∼670mAhg−1). Fast capacity fading and severe structural deterioration as a result of repeated lithium insertion restrict its application, however. Recently, we successfully synthesized a new type of MoS2/C composite and found that the composite showed excellent electrochemical performance, such as by its high capacity of 982mAhg−1 after 100 cycles. The composite was synthesized by a simplified thermal reduction method in which cetyl trimethylammonium bromide (CTAB) and silica nanospheres are used as the carbon source and template material, respectively. Such favorable capacity retention could be attributed to the large specific surface area due to the effective carbon dispersion in the composite, as well as the enlargement of the interlayer spacing in the S-Mo-S structure.
An overview of the recent development in the production of activated carbon electrodes from agricultural waste biomass for application in supercapacitors is presented. The use of agricultural waste biomass as precursor for the production of activated carbons has been on the increase lately because it is cheap, readily available and also viewed as a veritable way of combating waste disposal problem in the agricultural industries. The effects of activating methods (physical, chemical and microwave-induced) and conditions on the properties of activated carbons are reviewed. The survey of articles published in the last decade indicates the viability of biomass active carbons being used as electrodes in supercapacitors. Under optimum process conditions, active carbons with specific capacitance as high as 374Fg−1 and high-rate long-cycle stability at 4Ag−1 have been produced. In this review, the influence of surface modification on activated carbon properties is also discussed. From the survey literature, it can be seen that the changes in surface chemistry and the introduction of specific surface functionalities on the surface of activated carbons impacted more on the electrochemical properties than the physiochemical properties of the activated carbons.
Current density and potential distribution measurements were conducted using a segmented current collector and flow field setup on membrane electrode assemblies prepared with segmented and unsegmented electrodes made from two different types of commercially available gas diffusion layers. Both galvanostatic and potentiostatic discharge modes were employed. Irrespective of the type of gas diffusion layer, when a common electrode was employed, significant performance variations were encountered between current collector segments in the constant voltage mode, while the segment to segment variations were minimal in the constant current mode. Both types of discharge modes showed negligible variations between segments in the case of segmented electrode. A simple mathematical model was developed to assist in the interpretation of the experimental results. The differences in contact resistances between the current collectors and the gas diffusion layer, especially on the cathode side have been identified as the primary reason for the experimentally observed behavior. Based on the results presented here, segmenting the electrode along with the current collector is recommended for current distribution studies. When using a common electrode, only the galvanostatic mode is preferred to minimize contact artifacts.
Background Work stress and high job strain are linked to significant depression and anxiety in men. The literature points to the need for a greater focus on men's coping with occupational stress. There is a dearth of psychotherapeutic programs addressing issues of work stress in men. This article presents an Integrity Model perspective of occupational stress for men, with a focus on clinical interventions. Methods Through the use of three clinical vignettes, the Integrity Model – an existential model of psychotherapy examining the manner in which one honours one's personal values – is offered as a theoretical and therapeutic frame of reference for men to understand and resolve issues of significant work-related stress and burn-out. This model focuses on the importance of personal integrity, operationally defined as honesty, responsibility, and community, as a guide to daily living and addressing impasses and clashes between personal and organizational values. Conclusions This article provides clinical evidence for a therapeutic perspective that offers men who are grappling with occupational stress a philosophical and practical therapeutic working model validating their sense of honour, integrity and commitment to a responsible lifestyle as a means of developing a new resilience in addressing and resolving workplace impasses. It offers a new and valuing therapeutic perspective in reaching and assisting a wide range of men to deal with occupational stresses, addressing the literature's call for an approach that (a) works within men's own frameworks and (b) views men from a more positive, respectful and hopeful perspective.
We present a high-energy local power supply based on a flexible and solid-state supercapacitor for miniature wireless implantable medical devices. Wireless radio-frequency (RF) powering recharges the supercapacitor through an antenna with an RF rectifier. A power management circuit for the super-capacitive system includes a boost converter to increase the breakdown voltage required for powering device circuits, and a parallel conventional capacitor as an intermediate power source to deliver current spikes during high current transients (e.g., wireless data transmission). The supercapacitor has an extremely high area capacitance of ~1.3 mF/mm2, and is in the novel form of a 100 μm-thick thin film with the merit of mechanical flexibility and a tailorable size down to 1 mm2 to meet various clinical dimension requirements. We experimentally demonstrate that after fully recharging the capacitor with an external RF powering source, the supercapacitor-based local power supply runs a full system for electromyogram (EMG) recording that consumes ~670 μW with wireless-data-transmission functionality for a period of ~1 s in the absence of additional RF powering. Since the quality of wireless powering for implantable devices is sensitive to the position of those devices within the RF electromagnetic field, this high-energy local power supply plays a crucial role in providing continuous and reliable power for medical device operations.
The objective of this paper is to study the nonlinear coupled dynamical fractional model of romantic and interpersonal relationships using fractional variation iteration method (FVIM) and fractional homotopy perturbation transform method (FHPTM). These procedures inspect the dynamics of love affairs among couples. Sufficient conditions for their convergence and error estimates are established. Obtained results are compared with the existing and recently developed methods. It is interesting to observe that these methods also work for those fractional models that do not have an exact solution. Results for different fractional values of time derivative are discussed with the help of figures and tables. Figures are drawn using Maple package. Test examples are provided to illustrate the accuracy and competency of the proposed schemes. Results divulge those schemes that are attractive, accurate, easy to use and highly effective.
Natural abundance 17O and 6Li NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li+ at various concentrations of LiFSI in DME electrolytes. It was found that the chemical shifts of both 17O and 6Li changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME)2 forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li+ and FSI− ion increases, but the association between Li+ and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li+(FSI−)2(DME), Li+ 2(FSI−)(DME)4 and (LiFSI)2(DME)3 become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li+ decreases, and the coordinated number of FSI− increases, which is in perfect accord with the DFT results.