batterydata/paper-abstracts huggingface dataset:
The activated carbon in electrochemical double layer electrodes undergoes slow ageing. The effect becomes only apparent when capacitors are polarized to voltages at or above specified limits, or at high temperatures, for at least several months. A combination of “post mortem” analysis methods shows that the pores in the carbon are modified structurally, mainly by clogging up with organic species, but also electrochemically by decomposition of electrolyte, and by reduction and oxidation of the carbon in the electrodes. Key chemicals are trace water, the solvent acetonitrile, and the salt tetraethyl ammonium tetrafluoroborate. The changes differ hugely between negative and positive pole; the positively polarized electrode is much more affected. Also other compounds of the device, e.g. aluminum electrode support and paper separator, exhibit chemical ageing.
This paper reports on the development of polymer electrolyte membranes (PEMs) based on sulfonated polysulfone for application in a DMFC mini-stack operating at room temperature in passive mode. The sulfonated polysulfone (SPSf) with two degrees of sulfonation (57 and 66%) was synthesized by a well-known sulfonation process. SPSf membranes with different thicknesses were prepared and investigated. These membranes were characterized in terms of methanol/water uptake, proton conductivity, and fuel cell performance in a DMFC single cell and mini-stack operating at room temperature. The study addressed (a) control of the synthesis of sulfonated polysulfone, (b) optimization of the assembling procedure, (c) a short lifetime investigation and (d) a comparison of DMFC performance in active-mode operation vs. passive-mode operation. The best passive DMFC performance was 220mW (average cell power density of about 19mWcm−2), obtained with a thin SPSf membrane (70μm) at room temperature, whereas the performance of the same membrane-based DMFC in active mode was 38mWcm−2. The conductivity of this membrane, SPSf (IEC=1.34mequiv.g−1) was 2.8×10−2 Scm−1. A preliminary short-term test (200min) showed good stability during chrono-amperometry measurements.
The effects of temperature on the discharge and hydrogen evolution of lithium anode in 4M (molL−1) LiOH solutions were investigated via hydrogen collection, polarization and SEM (scanning electron microscope). It was found that the hydrogen evolution rate is low below 30°C with low discharge current density and the discharge current density is high over 30 with high hydrogen evolution rate. The lithium anode shows the better electrochemical performance with high discharge current density, low hydrogen evolution, and less porous film at 30°C at 0.94ms−1 in 4M LiOH solutions.
Iron/carbon-black composite nanoparticles were synthesized by chemically reducing the iron salt mixing with carbon black by adding NaBH4 in the aqueous solution. Carbon-black particles, with a mean particle size of approximately 40nm, function as the nucleation cores for iron deposition. Additionally, core–shell iron composite particles are observed to be 30–100nm with spherical sharp. At the first time discharge, the iron/carbon-black composite nanoparticle discharged 1200mAhg−1(Fe) at plateau one and 400mAhg−1at plateau two at a high current density of 200mAg−1(Fe). The capacity is larger than the theoretical value, which is attributed to the formation of iron hydride (FeH x ) while the iron was reduced by NaBH4, followed the hydrogen reaction as an active material while the battery discharge occurs. In further cycles, the iron/carbon-black composite iron electrode shows a good reversibility of about 600mAhg−1(Fe) when the nickel–iron battery operated between 1.65 and 0.8V. XRD analysis results indicate that the carbon black in the core of the iron/carbon-black composite enhances the reduction/oxidation reactions of iron, as achieved by the carbon black forming an enhanced electronic conductive network while iron is discharged as the insulator species such as Fe(OH)2 and Fe3O4. SEM images reveal that the iron/carbon-black composite keeps particle sizes smaller than 300nm during the electrode cycling, indicating that carbon black also acts as the nucleation cores for the dissolution–deposition of iron.
Designing and optimizing the flow-field structure for the liquid phase Br2/HBr electrolyte solution of H2/Br2 redox flow batteries (RFBs) is important for improving cell performance. In this study, two electrolyte flow modes, i.e. the flow-by and flow-through modes, are simulated by using a three-dimensional H2/Br2 RFB model. The model is first applied to real-scale H2/Br2 cell geometries and then validated against the experimental polarization curves acquired using the two different flow modes. The model predictions compare well with the experimental data and further highlight the advantages of using the flow-through mode relative to the flow-by mode. Detailed multi-dimensional contours of the electrolyte flow velocity and key species distributions reveal that more uniform diffusion and stronger convective transport are achieved by using the flow-through mode, which alleviates the ohmic loss associated with charge transport in the Br2 electrode.
One-dimensional magnetite (Fe3O4) nanowires were synthesized by the low temperature hydrothermal method. The as-prepared Fe3O4 nanowires were systematically characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. X-ray diffraction and transmission electron microscopy have confirmed the cubic structure of Fe3O4 nanowires with a space group of Fd 3 ¯ m. Electrochemical properties of Fe3O4 nanowires were tested as anodes in lithium-ion cells by cyclic voltammetry and galvanostatic charge/discharge. Fe3O4 nanowires exhibited an excellent reversible lithium storage capacity and a satisfactory cycling performance.
The aim of the present paper was to determine the electrochemical state of the positive electrodes during the formation process using the electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The investigations of typical positive electrodes were carried out for 12 states-of-electroformation (SOE). It was found that during electroformation the positive electrodes undergo dramatic changes which are reflected in EIS spectra. SOE strongly influences the equivalent electrical circuit and the range of impedance spectrum of non-inductive character. The obtained results showed that EIS technique can be used as a sensitive method allowing to distinguish the consecutive steps of electroformation. The conclusions drawn from EIS measurements are confirmed by CV measurements performed for selected SOEs.
Lithium ion capacitors are assembled with pre-lithiated mesocarbon microbeads (LMCMB) anode and activated carbon (AC) cathode. The effect of pre-lithiation degrees on the crystal structure of MCMB electrode and the electrochemical capacitance behavior of LIC are investigated by X-ray diffraction (XRD) and the charge-discharge test of three-electrode cell. The structure of graphite still maintained when the pre-lithiation capacity is less than 200 mAh g−1, phase transition takes place with the increase of pre-lithiation capacity from 250 mAh g−1 to 350 mAh g−1. Pre-lithiation degrees of MCMB anode greatly affect the charge-discharge process and behavior, which impact on the electrochemical performance of LIC. The LIC with pre-lithiation capacity of 300 mAh g−1 has the optimal electrochemical performance. The energy density of LIC300 is up to 92.3 Wh kg−1, the power density as high as 5.5kWkg−1 and the capacity retention is 97.0% after 1000 cycles. The excellent electrochemical performance benefits from the appropriate pre-lithiation capacity of negative electrode. The appropriate pre-lithiation ensures the working voltage of negative electrode in low and relative stable charge-discharge platform corresponding to the mutual phase transition from the second stage graphite intercalation compound (LiC12) to the first stage graphite intercalation compound (LiC6). The stable charge-discharge platform of negative electrode is conductive to the sufficient utilization of AC positive electrode.
The design and fabrication of fancy nanostructure materials, as a general method, are deemed to be essential for their applications in energy storage fields. Especially, encapsulating uniform functional nanomaterials in conductive carbon thin films can remarkably enhance the overall electrochemical performance. Herein, a sandwich-like composite, i.e., amorphous ZnSnO3 nanoparticles encapsulated in thin carbon nanosheets (ZnSnO3@C) was synthesized by using ZnSn(OH)6 nanosheets as template and ensuing surface glucose coating and annealling. While evaluated as an anode material in LIBs, the sandwich-like nanocomposite exhibits a significantly enhanced reversible capacity and cycling stability. This novel nanostructure may also be important for other applications, such as catalysis, sensing and electronic areas.
This study aims to investigate the impact of possible predictors of quality of life (QoL) in a group of Italian caregivers assisting a cancer patient in home palliative care.
This paper presents design viability studies and investigations of dual excitation switched-flux (DESF) motor as an applicant for traction drives in hybrid electric vehicles (HEVs). First of all, the main structure, the fundamental principle of operation and the design notion of the recommended DESF motor are discussed. Then, under certain limitations, specifications and performances of conventional interior permanent magnet synchronous (IPMS) motor, the preliminary performances of the recommended DESF motor are evaluated based on two-dimensional Finite Element Analysis (FEA). Since the initial performances fail to attain the target torque and power, design optimization based on deterministic approach of several DEFS motor parameters is applied in an attempt to attain the target performances. After a few cycles of design optimization, the improved DEFS motor has achieved the target power and torque of 123kW and 333Nm, respectively. In addition, due to definite advantage of robust rotor structure of DESF motor, rotor mechanical stress prediction at highest speed of 12,400r/min is much lower than the mechanical stress in conventional IPMS motor. In conclusion, the final design DESF motor has the maximum torque of 11.97Nm/kg and power density of 5.83kW/kg, which is approximately 26% and 66% more than the torque and power density in existing IPMS motor.
A thorough understanding of the mechanisms of ion crossover through the membranes in vanadium redox flow batteries (VRFBs) is critically important in making improvements to the battery’s efficiency and cycling performance. In this work, we develop a 2-D VRFB model to investigate the mechanisms of ion crossover and the associated impacts it has on the battery’s performance. Unlike previously described models in the literature that simulated a single cell by dividing it into the positive electrode, membrane, and negative electrode regions, the present model incorporates all possible ion crossover mechanisms in the entire cell without a need to specify any interfacial boundary conditions at the membrane/electrode interfaces, and hence accurately captures the Donnan-potential jumps and steep gradient of species concentrations at the membrane/electrode interfaces. With our model, a particular emphasis is given to investigation of the effect of the electric field on vanadium ion crossover. One of the significant findings is that an electric field exists in the membrane even under the open-circuit condition, primarily due to the presence of the H+ concentration gradient across the membrane. This finding suggests that vanadium ions can permeate through the membrane from H+-diluted to H+-concentrated sides via migration and convection. More importantly, it is found that the rate of vanadium ion crossover and capacity decay during charge and discharge vary with the magnitude of the electric field, which is influenced by the membrane properties and operating conditions. The simulations suggest that enhancing the electric-field-driven flow is a potential approach to minimizing the battery’s capacity decay.
Battery electric vehicles (BEV) have great potential of addressing the sustainability issues of the current, mostly fossil fueled individual mobility sector. Still, one of the major hurdles often cited in the context of electrifying individual mobility is range anxiety: conventional vehicles can be refueled within minutes and there is a dense network of fuel stations. So basically, as long as there's a road, no destination is out of reach. With BEVs however, charging may take hours, autonomy ranges are much shorter and currently, there is no widespread, international (or even interregional) public infrastructure to charge in case of emergency. That's why plugin-hybrids and range-extenders could play an important role as a transitory technology, offering high efficiency at the convenience of a conventional vehicle. This study explores this technological potential mainly in terms of well to wheel emissions, but also usability (range, handling, …). Different configurations, from “plugin-hybrids”, i.e. “chargeable hybrids” to “range-extenders”, i.e. BEVs with an auxiliary power unit (APU) and the corresponding operation strategies, from starting the APU at low battery charge to range-optimized, hybrid propulsion are looked at. The analysis also takes different driving conditions (rural, motorway, …) and chassis-types (from city-car to SUV) into account. The comparison to conventional vehicles and battery electric vehicles finally shows how on one hand, plugin-hybrids consist a step towards sustainability, and depends on the local electricity mixes’ carbon footprint.
The dielectric and conductivity study of two series of five three-dimensional hybrid inorganic–organic networks as polymer electrolytes (3D-HION-APEs), with formula {Al[O(CH2CH2O)8.7] ρ /(LiClO4) z } n (1.86≤ ρ ≤2.24, 0≤ z ≤1.06) and {Zr[O(CH2CH2O)8.7] ρ /(LiClO4) z } n (1.81≤ ρ ≤1.99, 0≤ z ≤0.91) is presented. The real and imaginary components of the complex dielectric permittivity spectra ɛ * and conductivity spectra σ * are measured between −60°C and 80°C. Spectral analysis points out that the conductivity mechanism is determined by two dielectric relaxation events, α and β. The relaxation β occurs at higher frequencies than α, and is attributed to the segmental motion with characteristic frequency f seg. The relaxation α is attributed to the ionic motion with characteristic frequency f ion. The profiles of the direct conductivity σ dc and the frequencies f ion and f seg vs. the reciprocal temperature exhibit a Vögel–Tamman–Fülcher (VTF) behavior. The study of the activation energies of the dielectric relaxations α and β allows to determine their relative contribution to the direct conductivity σ dc at lower and higher temperatures. The dependence of the VTF parameters vs. the mole-to-mole ratios n Li/n O and n Li/n M (M=Zr, Al) in combination with previous equivalent conductivity studies, allows to identify the role of the ionic species and the metal nodes present in the polymer structure at various salt concentrations. The correlation between the diffusion coefficient D and the relaxation frequencies f seg and f ion of the 3D-HION-APEs is investigated.
Electric power systems with substantial wind capacity require additional flexibility to react to rapid changes in wind farm output and mismatches in the timing of generation and demand. Controlled variable-rate charging of plug-in electric vehicles allows demand to be rapidly modulated, providing an alternative to using fast-responding natural gas plants for balancing supply with demand and potentially reducing costs of operation and new plant construction. We investigate the cost savings from controlled charging of electric vehicles, the extent to which these benefits increase in high wind penetration scenarios, and the trade-off between establishing a controlled charging program vs. increasing the capacity of generators in the power system. We construct a mixed integer linear programming model for capacity expansion, plant dispatch, and plug-in hybrid electric vehicle (PHEV) charging based on the NYISO system. We find that controlled charging cuts the cost of integrating PHEVs in half. The magnitude of these savings is ∼5% to 15% higher in a system with 20% wind penetration compared to a system with no wind power, and the savings are 50–60% higher in a system that requires capacity expansion.
The separator paper is a key component within a valve-regulated lead/acid (VRLA) battery. Here we describe an experimental program aimed at elucidating how separator papers influence battery performance. Identical batteries were manufactured using three different types of separator paper and subsequently cycled to failure. The failed batteries were then subjected to a series of tests, which included measurements of electrode potentials, compositional analysis of active materials, separator paper saturation and stratification measurements. Results indicated that separator paper type significantly influences battery performance. It is believed that subtle changes in the separator structure caused changes in the rate at which imbalances between the cells in each test battery developed, which led to subsequent changes in failure.
Lithium nitrate (LiNO3) is the most studied additive and co-salt for the electrolyte of lithium-sulfur (Li–S) batteries, its known function is to suppress the redox shuttle of soluble lithium polysulfide (PS, Li2Sn), which reflects as an increase in the battery’s coulombic efficiency and cycling stability, as well as a reduced self-discharge rate. The current understanding on this function is that LiNO3 reacts with Li to form a robust surface layer that consequently protects the Li anode from reacting with the dissolved PS. However, little is known on the sulfur cathode except that LiNO3 reduces and adversely affects the battery’s performance when the battery is discharged to lower than 1.7 V. In this paper we report a new finding on the role of LiNO3 in enabling the stable cycling of the sulfur cathode. We show that LiNO3 is capable of catalyzing the conversion of high soluble PS to slightly soluble elemental sulfur near the end of charging process, and that the combination of a soluble nitrate in the electrolyte and an insoluble nitrate in the sulfur cathode leads to synergetic improvement. In addition, a possible mechanism is proposed for the catalysis of LiNO3 on the conversion of PS to elemental sulfur.
Developmental Language disorders (DLD) are developmental disorders that can affect both expressive and receptive language. When severe and persistent, they are often associated with psychiatric comorbidities and poor social outcome. The development of language involves early parent-infant interactions. The quality of these interactions is reflected in the quality of the child’s attachment patterns.
Hippocampal NMDA receptors (NMDARs) and NMDAR-dependent synaptic plasticity are widely considered crucial substrates of long-term spatial memory, although their precise role remains uncertain. Here we show that Grin1ΔDGCA1 mice, lacking GluN1 and hence NMDARs in all dentate gyrus and dorsal CA1 principal cells, acquired the spatial reference memory water maze task as well as controls, despite impairments on the spatial reference memory radial maze task. When we ran a spatial discrimination water maze task using two visually identical beacons, Grin1ΔDGCA1 mice were impaired at using spatial information to inhibit selecting the decoy beacon, despite knowing the platform's actual spatial location. This failure could suffice to impair radial maze performance despite spatial memory itself being normal. Thus, these hippocampal NMDARs are not essential for encoding or storing long-term, associative spatial memories. Instead, we demonstrate an important function of the hippocampus in using spatial knowledge to select between alternative responses that arise from competing or overlapping memories.
The conductive polymer polyaniline (PANI) has various useful functions such as redox activity, color and conductivity changes depending on the oxidized state, reversible anion doping/dedoping and acid/base equilibria [1–3]. Some of the functions have already been utilized in devices such as lightweight secondary batteries, electrochromic displays, electromagnetic shielding devices and anticorrosion coatings. It has also been investigated for other practical uses [1–3]. There is no doubt that the morphology control of PANI, in particular, the control of the micro- and nanostructures, is a significant factor not only its the utilization, but also for the addition of new significant functions. For example, the nanofibrillar morphology improves the performance of PANI in most conventional applications involving polymer interactions with its environment [4]. This leads to much faster and more responsive chemical sensors, new inorganic-PANI nanocomposites and ultrafast nonvolatile memory devices [4].
Advances in lithium-ion battery technology since the last International Power Sources Symposium in Amsterdam in September 2003 are reviewed. Cost and safety are still seen as important factors limiting further expansion of application of lithium-ion batteries. Lithium bis-oxalato borate electolyte salt and lithium iron phosphate cathode material are being actively investigated.
Ever increasing acceptance of electric vehicles relies on better operation and control of large battery packs. The individual modules in large battery packs cannot have identical characteristics and may degrade differently due to manufacturing variability and other factors. Degraded battery modules waste more power, affecting the performance and economy for the whole battery pack. Also, such impact varies with different trip patterns. It is beneficial if the performance gain can be evaluated online prior to replacing certain battery module regarding to actual driving. In this paper, the research objectives are two-fold. First, we propose an on-line battery module degradation diagnostic scheme using the intrinsic signals of battery module equalization. Without need for additional sensors or offline tests, this scheme is cost-effective for constructing and updating the battery pack “health map” in real time during the vehicle operation. Secondly, based on the derived battery health map, the Worthiness of Replacement (WOR) for certain modules/cells is proposed to evaluate the performance of the battery pack for customer specified trip. Such evaluation index provides a quantitative measure for module replacement and battery pack swapping Simulation study is performed to validate the proposed ideas using an actual driving cycle recorded for a commuting trip.
The state of energy (SOE) of Li-ion batteries is a critical index for energy optimization and management. In the applied battery system, the fact that the discharge current and the temperature change due to the dynamic load will result in errors in the estimation of the residual energy for the battery. To address this issue, a new method based on the Back-Propagation Neural Network (BPNN) is presented for the SOE estimation. In the proposed approach, in order to take into account the energy loss on the internal resistance, the electrochemical reactions and the decrease of the open-circuit voltage (OCV), the SOE is introduced to replace the state of charge (SOC) to describe the residual energy of the battery. Additionally, the discharge current and temperature are taken as the training inputs of the BPNN to overcome their interference on the SOE estimation. The simulation experiments on LiFePO4 batteries indicate that the proposed method based on the BPNN can estimate the SOE much more reliably and accurately.