batterydata/paper-abstracts huggingface dataset:
To identify the mechanism of exothermic reactions of cycled FeF3 electrodes in an electrolyte with temperature ramp-up, the structure and thermal behavior of cycled FeF3 electrodes were investigated using a combination of XRD and DSC. The combination of XRD and DSC revealed that FeF3 can be restored and the electrochemical was reversible even after the conversion reaction. In the discharged electrodes, a structural transformation to LiFeF3 was observed after 1Li insertion, and two compounds (LiF and Fe metal) were formed during the conversion reaction. Accordingly, the differences of thermal behavior in the electrolyte were presented in the DSC curves. It was clear that no reaction occurred between LiF and the electrolyte at elevated temperatures. In contrast, Fe powder was found to react with the electrolyte at around 300°C, indicating that Fe metal generated in the electrode had a direct effect on the thermal behavior of the discharged FeF3 electrode. Moreover, Fe powder was found to react with PF5 produced by LiPF6 decomposition. The mixture of discharged FeF3 electrode and electrolyte showed less heat generation than the electrolyte alone because some PF5 was consumed by the generated Fe metal in the electrode.
Redox-active small molecules, used traditionally in redox flow batteries (RFBs), are susceptible to crossover and require expensive ion exchange membranes (IEMs) to achieve long lifetimes. Redox-active polymer (RAP) solutions show promise as candidate electrolytes to mitigate crossover through size-exclusion, enabling the use of porous separators instead of IEMs. Here, poly(vinylbenzyl ethyl viologen) is studied as a surrogate RAP for RFBs. For oxidized RAPs, ionic conductivity varies weakly between 1.6 and 2.1 S m−1 for RAP concentrations of 0.13–1.27 mol kg−1 (monomeric repeat unit per kg solvent) and 0.32 mol kg−1 LiBF4 with a minor increase upon reduction. In contrast, viscosity varies between 1.8 and 184.0 mPa s over the same concentration range with weakly shear-thinning rheology independent of oxidation state. Techno-economic analysis is used to quantify reactor cost as a function of electrolyte transport properties for RAP concentrations of 0.13–1.27 mol kg−1, assuming a hypothetical 3V cell and facile kinetics. Among these concentrations, reactor cost is minimized over a current density range of 600–1000 A m−2 with minimum reactor cost between $11–17 per kWh, and pumping pressures below 10 kPa. The predicted low reactor cost of RAP RFBs is enabled by sustained ionic mobility in spite of the high viscosity of concentrated RAP solutions.
Following privatisation of the electricity industry in 1990, the role of Capenhurst changed with greater emphasis to a more independent commercial organisation and Peter was appointed the head of the Environmental Division. The new role embraced not only electrochemistry and chemistry for clean manufacturing, materials recycling and effluent treatment, but many other scientific areas, including high temperature ceramics, a three phase plasma unit for the destruction of chloro-organics, a novel atmospheric pressure microwave plasma, and metallurgically related projects, to list but a few.
The fuel cell hybrid bus (FCHB) program was initiated at the University of Delaware in 2005 to demonstrate the viability of fuel cell vehicles for transit applications and to conduct research and development to facilitate the path towards their eventual commercialization. Unlike other fuel cell bus programs, the University of Delaware's FCHB design features a battery-heavy hybrid which offers multiple advantages in terms of cost, performance and durability. The current fuel cell hybrid bus is driven on a regular transit route at the University of Delaware. The paper describes the baseline specifications of the bus with a focus on the fuel cell and the balance of plant. The fuel cell/battery series-hybrid design is well suited for urban transit routes and provides key operational advantages such as hydrogen fuel economy, efficient use of the fuel cell for battery recharging, and regenerative braking. The bus is equipped with a variety of sensors including a custom-designed cell voltage monitoring system which provide a good understanding of bus performance under normal operation. Real-time data collection and analysis have yielded key insights for fuel cell bus design optimization. Results presented here illustrate the complex flow of energy within the various subsystems of the fuel cell hybrid bus. A description of maintenance events has been included to highlight the issues that arise during general operation. The paper also describes several modifications that will facilitate design improvements in future versions of the bus. Overall, the fuel cell hybrid bus demonstrates the viability of fuel cells for urban transit applications in real world conditions.
There is growing evidence based on behavioral and functional imaging studies about the cerebellar involvement in the modulation of cognitive functions. However, it still remains to be clarified how the cerebellum interacts with brain regions sub-serving different cognitive domains. In this study we used magnetic resonance imaging (MRI) and voxel based morphometry (VBM) to investigate changes of cerebral gray matter (GM) density in 15 patients with a focal cerebellar damage (CD) compared to 15 healthy controls. T2-weighted scans and T1-weighted volumes were collected from each subject. With the exception of the cerebellar lesion, none of the patients showed any additional brain MRI abnormality. T1-volumes were analyzed by voxel-based morphometry. Consistent with their neuropsychological abnormalities, patients with right-CD compared to controls showed a reduction of GM density mainly involving the left frontal, parietal and temporal lobes. Conversely, patients with left-CD did not show any significant neuropsychological or cerebral GM abnormality. The present study indicates that specific GM changes may be detected in patients with isolated CD and cognitive dysfunction. We discuss the findings in terms of cerebellar influence on the neuronal networks involved in higher level functions of the association cortex.
The viscosity of the electrolyte in vanadium redox flow batteries (VRFBs) varies during charge and discharge as the concentrations of acid and vanadium ions in the electrolyte continuously change with the state of charge (SOC). In previous VRFB models, however, the electrolyte has been treated as a constant-viscosity solution. In this work, a mass-transport and electrochemical model taking account of the effect of SOC-dependent electrolyte viscosity is developed. The comparison between the present model and the model with the constant-viscosity simplification indicates that the consideration of the SOC-dependent electrolyte viscosity enables (i) a more realistic simulation of the distributions of overpotential and current density in the electrodes, and (ii) more accurate estimations of pumping work and the system efficiency of VRFBs.
Germanium oxide is a promising anode material for lithium ion batteries due to its theoretical capacity (1100mAh/g) is 3 times higher than the commercial graphite anode (only 372mAh/g). However, so far only a few studies have reported the application of germanium oxide in LIBs and the cycling performance is unsatisfactory. In this report, we have prepared a unique VAG@ amorphous GeO x sandwich nanostructure by a non-toxic, low temperature CVD method with vertically aligned graphene(VAG) as templates. The graphene sheets form a fast electron transport channel duo to its superior electron conductivity and the vertically aligned sandwich nanoflakes can offer a short pathway for lithium ion thanks to the unified orientation. Additionally, the GeO x sediments that evenly distribute on the surface of graphene flakes have an amorphous structure and their thickness is less than 10nm, which can mitigate the mechanical stress generating in the lithiation/delithiation process. Owing to these advantages, the as-prepared anode shows a stable capacity of 1008mAh/g for 100 cycles (with capacity retention of 96%). Rate performance reveals the anode can maintain a capacity of 545mAh/g even at the rate of 15C. Our results are demonstrated to be so far the most stable performance for germanium oxide anodes.
A novel nanocomposite of crystalline Li4Ti5O12-coated TiO2 nanotube arrays (Li4Ti5O12/TNTA) was synthesized by anodic oxidation and sol-gel method as three-dimensional (3D) anode for Li-ion batteries. The 3D nanotubular structure was well retained in Li4Ti5O12/TNTA, and the pure and nanocrystalline Li4Ti5O12 formed on the surface of TNTA by the simple, template-free and low-temperature process. The morphology and microstructure of the samples were investigated by glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). In addition, the electrochemical performance was further evaluated by charge-discharge measurements and electrochemical impedance spectroscopy (EIS), and the formation mechanism of nanocrystalline of Li4Ti5O12 was discussed. The results showed that the new phase Li4Ti5O12 separated the phases of anatase and rutile, and hindered the phase transformation of anatase to rutile severely due to the steric hindrance effect, moreover nanocrystalline Li4Ti5O12 coating bonded TNTA firmly and improved the stability of the porous tubular structure. Li4Ti5O12/TNTA anode with the novel nanostructure exhibited higher electrochemical performance than that of TNTA. The areal capacity of Li4Ti5O12/TNTA anode is 400.9μAhcm−2 at the current density of 10μAcm−2, after 50 cycles of different current density it retains 175.8μAhcm−2, which is almost tripled of TNTA 63.9μAhcm−2.
Cycle stability is crucial for non-aqueous lithium-oxygen batteries, which is dependent with the cathode performance. In this work, gadolinium doped CeO2 nanoparticles are prepared through one-pot hydrothermal process on reduced graphene oxide, and applied as cathode catalyst for non-aqueous lithium-oxygen batteries. With the catalytic effect of Ce0.8Gd0.2O2-δ nanoparticles on Li2O2 formation and decomposition, the battery delivers both low discharge and charge overpotential about 0.18 V and 0.69 V at the current density of 400 mA g−1. Moreover, cycle stability is enhanced for over 100 times at the capacity limitation of 600 mAh·g−1. The superiority may attribute to the enhanced stabilization of Ce0.8Gd0.2O2-δ nanoparticles through doping process, which can preserve the nanoparticles from migration and aggregation during cycle process.
The electrochemical performance of the carbon-coated Li3V2(PO4)3 (LVP/C) composite prepared through a carbon thermal reduction route has been investigated. The results show that the LVP/C composite exhibits reversible Li+ de-intercalating/intercalating behaviors with the swing potential in the range of −0.2 to 0.8V vs. SCE in a neutral Li2SO4 aqueous solution. It has also been found that the activated carbon (AC)//LVP/C asymmetric hybrid capacitor exhibits good electrochemical properties. The asymmetric hybrid capacitor shows sloping profiles in the galvanostatic charge–discharge curves with the operating voltage in the range of 0–1.7V and can work steadily. Both of the capacity retention and coulombic efficiency of the asymmetric hybrid capacitor can retain more than 90% after 1000 charge–discharge cycles at a current density of 250mAg−1. At the power density of 102Wkg−1, the energy density of the asymmetric hybrid capacitor is 35Whkg−1, and even at 2000Wkg−1, the energy density can achieve 5Whkg−1. In addition, we have found that the conductive additive such as acetylene black is not required during the electrode fabricating process with the LVP/C composite as an electrode material, and this will serve the interest of saving cost. This work could provide an evidence for the development of aqueous asymmetric hybrid capacitors using LVP/C as electrode materials.
Olivine LiFePO4 and LiFePO4/C are successfully prepared by a simple solid-state reaction using FePO4·2H2O, lithium oxalate and glucose (bare LiFePO4 without adding glucose) as raw materials. The structure of the LiFePO4 and LiFePO4/C is investigated by X-ray diffraction (XRD). The micromorphology of LiFePO4 and LiFePO4/C is observed using scanning electron microscopy (SEM) and BET, and the in situ coating of carbon on the particles is observed by transmission electron microscopy (TEM) and Raman spectrum. Furthermore, the electrochemical properties are evaluated by cyclic voltammograms (CVs), electrochemical impedance spectra (EIS) and constant current charge/discharge cycling tests. The results show that carbon coated LiFePO4 can deliver better battery performance than the bare LiFePO4. It exhibits initial discharge capacities of 162, 142 and 112mAhg−1 at rates of 0.1, 1 and 10C, respectively, and it presents excellent capacity retention as there is tiny capacity fade after 100cycles. Moreover, the reductive mechanism of using lithium carboxylic acid to synthesize LiFePO4 is firstly mentioned.
A liquid tin anode solid oxide fuel cell is constructed and investigated under different operating conditions. Electrochemical Impedance Spectroscopy (EIS) is used to reflect the effect of fuel feed as the EIS spectra changes significantly on switching the fuel from argon to hydrogen. A cathode symmetric cell is used to separate the impedance from the two electrodes, and the results indicate that a major contribution to the charge-transfer and mass-transfer impedance arises from the anode. The OCP of 0.841 V for the cell operating under argon as a metal-air battery indicates the formation of a SnO2 layer at the electrolyte/anode interface. The increase in the OCP to 1.1 V for the hydrogen fueled cell shows that H2 reduces the SnO2 film effectively. The effective diffusion coefficients are calculated using the Warburg element in the equivalent circuit model for the experimental EIS data, and the values of 1.9 10−3 cm2 s−1 at 700 °C, 2.3 10−3 cm2 s−1 at 800 °C and 3.5 10−3 cm2 s−1 at 900 °C indicate the system was influenced by diffusion of hydrogen in the system. Further, the performance degradation over time is attributed to the irreversible conversion of Sn to SnO2 resulting from galvanic polarization.
High-quality crystalline ZnSe thin film has been successfully fabricated by using pulsed laser ablation of mixed target of Zn and Se. The physical, electrochemical and spectroelectrochemical properties of the as-deposited thin film at different substrate temperatures have been investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), the charge/discharge, cyclic voltammetry (CV) and in situ absorbance spectra measurements. The thin film deposited at room temperature consisted of a mixture of Zn and Se. When the substrate temperature was elevated to 300°C, the as-deposited thin film was composed of crystallized ZnSe. The cycle performance of ZnSe/Li cell is well than that of Zn–Se/Li cell. A couple of reduction and oxidation peaks at 0.51 and 1.4V from CV curves of ZnSe/Li cell was found, indicating the reversible formation and decomposition of Li2Se. Both classical alloying/dealloying processes and the partially selenidation/reduction of nano-sized metal zinc were proposed in lithium electrochemical reaction of ZnSe. The high degree of crystallinity in the zinc alloys and the slow kinetics should be responsible for a large irreversible capacity loss and poor cyclability.
Disability in older adults is associated with loss of independence, institutionalization, and death. The aim of this study was to study the association between the Timed Up and Go (TUG) test and all-cause mortality in a population-based sample of older men and women.
Ni(OH)2 has been reported widely as one of the most promising supercapactior electrode materials due to its high specific capacitance, yet which were only based on low mass loading. Thus, it is desirable to promote supercapacitor performance for high mass loading Ni(OH)2 through optimizing microstructure. In this work, we first prepared crossed ultrathin Ni(OH)2/ZnO nanoleafs directly grown on nickel foam via hydrothermal method, and then we produced pores on the nanoleafs by dissolving ZnO in alkaline solution. Definitely, this unique structure design for high mass loading binder-free Ni(OH)2 electrode could benefit the penetration of electrolyte and the transportation of electrons, efficiently improving the supercapacitor performance. The obtained porous Ni(OH)2/NF electrode exhibits a mass specific capacity of 1142Cg−1 based on 10mg active materials, equating to a areal specific capaciy of 11.4Ccm−2, and pleasant cycling stability with retention of 85% of initial capacity after 10000 charge-discharge cycles. The fabricated asymmetric device shows a high energy density of 42 Wh kg−1 (4.73 mWh cm−3) at power density of 105Wkg−1 (17mWcm−3). These results demonstrate the optimized structure makes the high mass loading binder-free Ni(OH) 2/NF electrode could also display excellent supercapacitor performance.
Cobalt (II) fluoride begins to enter into the horizons of people along with the research upsurge of metal fluorides. It is very significative and theoretically influential to make certain its electrochemical reaction mechanism. In this work, we discover a new and unrevealed reversible interfacial intercalation mechanism reacting below 1.2V for cobalt (II) fluoride electrode material, which contributes a combined discharge capacity of about 400mAhg−1 with the formation of SEI film at the initial discharge process. A highly reversible storage capacity of 120mAhg−1 is observed when the cell is cycled over the voltage of 0.01-1.2V at 0.2C, and the low-potential voltage reaction process has a significant impact for the whole electrochemical process. Electrochemical analyses suggest that pure cobalt (II) fluoride shows better electrochemical performance when it is cycled at 3.2-0.01V compared to the high range (1.0-4.5V). So, we hold that cobalt (II) fluoride is more suitable to serve as anode material for lithium ion batteries. In addition, we also try to reveal the relevant performance and reaction mechanism, and realize the possibility of cobalt (II) fluoride as anode material for sodium ion batteries.
A cold cranking test for 17 sealed lead-acid batteries with grids of lead–calcium alloy at −18°C was performed at different discharge currents. Time–voltage behavior of the batteries during 10s discharge, voltage values at discharge times of 30, 60 and 90s, and time of discharge to reach a final voltage of 6V are critical points in the cold cranking test. These were modeled by artificial neural networks in MATLAB 7 media. Nine discharge currents were used for the training set, five discharge currents for the prediction set and three discharge currents for the validation set. Maximum prediction errors in the modeling of the time-voltage behavior during a 10s discharge (model 1), the voltage of critical points of 30, 60, 90s (model 2) and the time to reach a final voltage of 6V (model 3) were under 3.1%, 3.3%, and 3.5%, respectively for each model. The results obtained showed that the models can be used in the battery industry for the prediction of the cold cranking behavior of lead-acid batteries at high discharge currents based on experimental cold cranking data at low discharge currents without the use of expensive and complex instruments. A file (EXE file) based on the model obtained by WinNN 32 was prepared to enable inexpert operators in the lead-acid battery industry to use the method.
Well-defined submicron Li4Ti5O12-Li3xLa(2/3)−xTiO3 (LTO-LLTO) materials have been synthesized by a solid-state reaction followed by hydrothermal procedure. Li4Ti5O12-Li3xLa(2/3)−xTiO3 materials show much improved rate capability and specific capacity compared with pristine Li4Ti5O12 when used as anode materials for lithium-ion batteries. The results here give clear evidence of the utility of Li3xLa(2/3)−xTiO3 (LLTO) to improve the kinetics of Li4Ti5O12 toward fast lithium insertion/extraction. LTO-LLTO (10 wt%) shows a high capacity of 101 mAh g−1 even at a charge-discharge rate of 5 C in the 150th cycle, about 150% that of pristine Li4Ti5O12 particles (68 mAh g−1). The improved high-rate capability, cycling stability, fast charge-discharge performance of LTO-LLTO composites can be ascribed to the improvement of electrochemical reversibility, lithium ion diffusion and ionic conductivity by LLTO modifying.
Carbon matrix (CM) derived from biomass is low cost and easily mass produced, showing great potential as sulfur host for lithium sulfur batteries. In this paper we report on a dihydrogen phosphate modified CM (PCM-650) prepared from luffa sponge (luffa acutangula) by phosphoric acid treatment. The phosphoric acid not only increases the surface area of the PCM-650, but also introduces dihydrogen phosphate onto PCM-650 (2.28 at% P). Sulfur impregnated (63.6 wt%) PCM-650/S, in comparison with samples with less dihydrogen phosphate LPCM-650/S, shows a significant performance improvement. XPS analysis is conducted for sulfur at different stages, including sulfur (undischarged), polysulfides (discharge to 2.1 V) and short chain sulfides (discharge to 1.7 V). The results consistently show chemical shifts for S2p in PCM-650, suggesting an enhanced adsorption effect. Furthermore, density functional theory (DFT) calculations is used to clarify the molecular binding: carbon/sulfur (0.86 eV), carbon/Li2S (0.3 eV), CH3-O-PO3H2/sulfur (1.24 eV), and CH3-O-PO3H2/Li2S (1.81 eV). It shows that dihydrogen phosphate group can significantly enhance the binding with sulfur and sulfide, consistent with XPS results. Consequently a CM functionalised with dihydrogen phosphate shows great potential as the sulfur host in a Li-S battery.
In this research a simple, yet accurate model of a single cell, needed for safety assessment of batteries under mechanical abuse conditions, was developed. Extensive testing was performed on a 18650 lithium ion cell, including indentation by a hemispherical punch, lateral indentation by a cylindrical rod, compression between two flat plates, and three-point bending. The batteries were tested in an environmental chamber at a 10% SOC. A finite element model was developed, composed of shell elements representing outside casing, and solid elements for the active material with a binder lumped together with the current collectors and the separator. The jelly roll is modeled as a homogenized and isotropic material. The homogenous model assumes different properties in tension and compression, but does not account for the effect of structural anisotropy caused by the layered nature of the jelly roll. Very good correlation was obtained between LS Dyna numerical simulation and test results in terms of load–displacement relations, deformed shape of the battery, and initiation and propagation of a crack in the shell casing. The FE model was also capable of predicting the onset of short circuit of the cell.
There is a huge burden of patients suffering from trauma-induced disabling spasticity the world over. There are surprisingly few modalities of treatment with a sustained, proven benefit which can be offered to such patients. Selective dorsal rhizotomy (SDR) has been used with proven success in treating spasticity in patients of cerebral palsy, both in children and in adults. The rationale behind using the procedure in post-traumatic cases is reviewed, along with the cases reported till date in the world literature. The indications, surgical procedure used, outcome and complications, if any, are described. Most of the cases described in the literature have shown a favourable outcome with minimal complications. SDR can become an important tool in the armamentarium of the clinician treating this condition.