batterydata/paper-abstracts huggingface dataset:
The co-precipitation derived LiNi0.8Co0.15Al0.05O2 cathode material was modified by a coating layer of TiP2O7 through an ethanol-based process. The TiP2O7-coated LiNi0.8Co0.15Al0.05O2 is characterized by X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy to investigate the microstructure and morphology. The differential scanning calorimetry was employed to confirm the improved thermal stability. The electrochemical properties were evaluated by the constant-current charge/discharge tests. The TiP2O7 coating layer is effectively suppressing the structural degradation and ameliorating the surface status of LiNi0.8Co0.15Al0.05O2 particles, and the intrinsic rhombohedral layered structure of TiP2O7-coated LiNi0.8Co0.15Al0.05O2 was well maintained during the long-term cycling process, while the surface structure of pristine LiNi0.8Co0.15Al0.05O2 was degraded from rhombohedral R3m layered structure to cubic rock-salt structure. The charged state Ni4+ ions will easily transform into Ni2+ when the electrolytes oxidized at the interface of cathode/electrolytes and formed the cubic rock-salt NiO type structure, and the cubic rock-salt structure without electrochemical activity on the surface of LiNi0.8Co0.15Al0.05O2 particles will finally accelerate capacity fading. The thermal stability and cyclic performances of the LiNi0.8Co0.15Al0.05O2 electrode were remarkably improved by TiP2O7 coating, the total amount of heat release corresponding to the intensity of thermal runaway were 1075.5 and 964.6 J/g for pristine LiNi0.8Co0.15Al0.05O2 and TiP2O7-coated LiNi0.8Co0.15Al0.05O2 respectively, the pouch shaped full cells that employed TiP2O7-coated LiNi0.8Co0.15Al0.05O2 as cathode were able to perform more than 2200 cycles at 25 °C and more than 1000 cycles at 45 °C before the capacity retention fading to 80%.
A binder-free three-dimensional (3D) porous Cu6Sn5 anode was prepared for lithium-ion batteries. In this novel approach, tin was deposited by electroless-plating on copper foam which was served as anode current collector as well as the source of copper for Cu6Sn5 alloy formation. With optimized post-treatment condition, Cu6Sn5 alloy with thickness of 1.2μm was formed on the surface of copper foam network. 3D porous Sn–Cu6Sn5 and Cu3Sn–Cu10Sn3–Cu6Sn5 composite anodes were also prepared for comparison. Electrochemical tests showed that 3D porous Cu6Sn5 anode exhibits the best electrochemical performance in terms of specific capacitance and cycleability, which delivers a rechargeable capacity of 404mAhg−1 over 100 cycles.
Predictive modelling of estuarine sediment erosion and transport requires a description of the erosional properties of the bed. The two main variables of interest are the critical erosion shear stress (τ cr) and the erosion rate (ε). A number of different erosion devices exist to measure the erosion shear stress of intertidal sediments in situ. These devices apply different strategies to induce and measure erosion, and the area over which erosion is integrated varies greatly. In addition, the definition of erosion threshold differs between workers. This makes comparison of data collected from different devices very difficult. Four different types of erosion device, Microcosm system, In Situ Erosion Flume (ISEF), SedErode and cohesive strength meter (CSM) were used during the July 1997 EC INTRMUD Humber estuary (UK) field campaign. These devices were deployed simultaneously on the Skeffling intertidal mudflat to allow comparison of the data generated. This involved the comparison of suspended particulate matter (SPM) time series, the nature of the applied shear stress (τ o) and the area over which erosion was integrated. The initial goal was to develop a standard analysis procedure for comparison of stability measurements. The erosion threshold calculated from area normalised suspended particulate matter (SPMn) time series was relatively comparable between devices especially between the Microcosm and ISEF. However, device size and natural sediment spatial heterogeneity affected the results. The erosion rate varied by orders of magnitude between the different devices. This variation seemed to be due to the considerable differences in device deployment time. In conclusion, SPM data from different devices are broadly comparable, whilst erosion rates are only comparable if the shear stress steps are of the same duration.
Porous graphite felts have been used as electrode materials for all-vanadium redox flow batteries due to their wide operating potential range, stability as both an anode and a cathode, and availability in high surface area. In this paper, the carbon felt was modified by pyrolysis of Ir reduced from H2IrCl6. ac impedance and steady-state polarization measurements showed that the Ir-modified materials have improved activity and lowered overpotential of the desired V(IV)/V(V) redox process. Ir-modification of carbon felt enhanced the electro-conductivity of electrode materials. The Ir-material, when coated on the graphite felt electrode surface, lowered the cell internal resistance. A test cell was assembled with the Ir-modified carbon felt as the activation layer of the positive electrode, the unmodified raw felt as the activation layer of the negative electrode. At an operating current density of 20mAcm−2, a voltage efficiency of 87.5% was achieved. The resistance of the cell using Ir-modified felt decreased 25% compared to the cell using non-modified felt.
The kinetics of the oxygen reduction reaction (ORR) was studied on ultra thin layer electrodes formed by bimetallic Ag-Co nanoparticles dispersed on a carbon powder (Ag-Co/C) in KOH electrolyte. The morphological features of the materials were studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Cyclic voltammetry and steady state polarization measurements for the ORR were obtained using the rotating ring/disk electrode (RRDE) technique. TEM measurements for the bimetallic Ag-Co/C catalysts showed a heterogeneous crystallite size distribution and, together with XRD, suggested the presence of a segregated phase of cobalt, mainly as Co3O4. The characterization of the materials by XRD also showed a negligible decrease in the Ag face centered cubic (fcc) lattice parameter, which was ascribed to a negligible Co insertion into the Ag structure. Levich plots obtained from rotating disk electrode data have shown a higher number of electrons for the Ag-Co/C materials, compared to Ag/C. The polarization results showed higher activity for the ORR on Ag-Co/C materials in comparison to Ag/C.
Li2ZrO3 anode materials were prepared by the conventional solid-state reaction. The crystal structure has been determined by X-ray diffraction. Electrochemical tests show that Li2ZrO3 anode materials process a excellent cycle performance and rate capability due to the good structural stability and high lithium diffusion coefficients. For the Li2ZrO3 anode material, the change of the unit cell volume is only ∼0.3% at discharge or charge process. Except for the first several cycles, the coulombic efficiency of the Li2ZrO3 electrode was nearly 100% at a discharge/charge rate of 0.3C. The lithium diffusion coefficients of Li2ZrO3 for the reduction and oxidation process are calculated to be 3.165×10−6 and 1.919×10−6 cm2 s−1 respectively which is much higher than that of the Li4Ti5O12 anode material (about 10−9 to 10−13 cm2 s−1). In situ XRD results, combined the sloping character of the charge/discharge voltage profiles and the lithium ion diffusion controlled mechanism in the charge and discharge process, show that the insertion/extraction mechanism of Li+ for Li2ZrO3 can be interpreted as a solid-solution behavior.
C1-xBx samples with 0≤x≤0.60 have been prepared by magnetron sputtering and ball milling. The effect of the boron concentration on the structure and performance of C-B samples as negative electrode materials in lithium and sodium cells were examined by X-ray diffraction and electrochemical methods. XRD experiments of all of the prepared samples show diffraction patterns characteristic of amorphous or nanostructured materials. The boron concentration was found to have a significant effect on the reversible capacity, initial coulombic efficiency and voltage of carbon electrodes. In lithium cells, the reversible capacities increase with increasing boron concentration for both sputtered and ball milled samples, however, the initial coulombic efficiency is lower than 80%. In Na batteries, boron has little effect on the reversible capacity and only increases the irreversible capacity and all electrodes have initial coulombic efficiencies that are lower than 40%. Crystallinity improvement of the C-B alloys structure is required for them to be of practical use in Na or Li cells.
Two-dimensional rod-shaped carbon coated V6O13 was prepared by simple solvothermal method using V2O5, C2H5O7 (Ethanol absolute) and C6H12O6 (Glucose) as raw materials. The results indicated that proper carbon coating improved the cycle stability of V6O13. The carbon coated V6O13 composites (CNPs-V6O13) exhibit a capacity retention of 67.8% after 100cycles at 0.1 C (42mA/g) and a discharge capacity of 227.93 mAh/g after 100cycles at 1 C, comparing to those of the pure V6O13 of only 47.6% and 51.2 mAh/g. The results of EIS and XPS tests provide evidence that the improved electrochemical properties are mainly attributed to the suppress the irreversible chemical dissolution of V3+ and the improvement of structural stability of the material by coating.
A summary of the activity performed in the investigation of metallic alloys over many years is presented. General attention is given to research carried out by using thermoanalytical techniques and their application to the determination of phase diagrams. The results obtained in the systematic investigation of several binary and ternary systems involving rare earth metals are briefly outlined and discussed within a more general picture of the alloying behaviour of these metals. A report with reference to the groups of alloys especially investigated and to a number of experimental difficulties encountered and solutions adopted is given.
Novel lithium salts of borates having two electron-withdrawing groups (either 1,1,1,3,3,3-hexafluoro-2-propoxy or pentafluorophenoxy group) and two methoxy-oligo(ethylene oxide) groups (number of repeating unit: n = 3, 4, 7.2) were prepared by successive substitution-reactions from LiBH4. The obtained lithium salts were clear and colorless liquids at room temperature. The density, thermal property, viscosity, and ionic conductivity were measured for the lithium ionic liquids. The pulsed-gradient spin-echo NMR (PGSE-NMR) method was used to independently determine self-diffusion coefficients of the lithium cation (7Li NMR) and the anion (19F NMR) in the bulk. The ionic conductivity of the new lithium salts was 10−5 to 10−4 Scm−1 at 30°C, which was lower than that of typical ionic liquids by two orders of magnitude. However, the degree of self-dissociation of the lithium ionic liquids; the ratio of the molar conductivity determined by the complex impedance method to that calculated from the self-diffusion coefficients and the Nernst–Einstein equation, ranged from 0.1 to 0.4, which are comparable values to those of a highly dissociable salt in an aprotic polar solvent and of typical ionic liquids. The main reason for the meager conductivity was high viscosities of the lithium ionic liquids. It should be noted that the lithium ionic liquids have self-dissociation ability and conduct the ions in the absence of organic solvents.
Secure transmission of multimedia contents is computationally challenging due to the sheer volume of data involved, and achieving this by fully encrypting multimedia contents is not a viable solution for mobile devices, as they run on limited battery power and employ relatively slower processors compared to their desktop counterparts. Also, in some particular application scenarios, the value, secrecy, and/or privacy of the information is time dependent and short lived. This paper presents a highly scalable approach for securing multimedia streams on mobile devices by encrypting intelligently only selected portions of the bit stream. More importantly, the proposed solution works mainly on compressed bit stream and does not require any media decoding. It encrypts on the average less than 3% of a packet load and provides robust security equivalent to that of a fully encrypted bit stream. This solution has been implemented on desktop, laptop, netbook and Nokia N series platforms. The proposed scheme is approximately 15 times faster (on average) and processes 8 to 12 times more information for a given battery life when compared to a state of the art full encryption based solutions.
Norwegian Psychomotor Physiotherapy (NPMP) has been an established treatment approach for more than 50 years, although mostly in the Scandinavian countries, and is usually applied to patients with widespread and long-lasting musculoskeletal pain and/or psychosomatic disorders. Few studies have been investigating outcome of NPMP and no randomized clinical trials (RCT) have been systematically tried out on individuals.
Dodecylsulfate-intercalated α-hydroxides of nickel and cobalt delaminate to give colloidal dispersions in 1-butanol. When these colloidal dispersions are mixed in different proportions and evaporated, composites are obtained and these consist of a random stacking of layers from the two hydroxides. The surfactant anion of these composites can be exchanged with nitrate ions and the resultant nitrate-intercalated composites are very stable in alkaline medium and show a high reversible charge capacity.
Objectives To assess the feasibility and efficacy of delivering Pilates exercises for resistance training to breast cancer survivors using the MVe Fitness Chair™. Design Pilot randomized controlled trial. Methods Twenty-six female breast cancer survivors were randomized to use the MVe Fitness Chair™ (n =8), traditional resistance training (n =8), or a control group (no exercise) (CO) (n =10). The MVe Fitness Chair™ and traditional resistance training groups completed 8 weeks of exercise. Muscular endurance was assessed pre and post-test for comparisons within and between groups using push ups, curl ups, and the Dynamic Muscular Endurance Test Battery for Cancer Patients of Various Ages. Results Feasibility of the MVe Fitness Chair™ was good, evidenced by over 80% adherence for both exercise groups and positive narrative feedback. Significant improvements in muscular endurance were observed in the MVe Fitness Chair™ (p <0.002) and traditional resistance training groups (p <0.001), but there were no differences in improvement between the MVe Fitness Chair™ and traditional resistance training groups (p <0.711) indicating that Pilates and traditional resistance training may be equally effective at improving muscular endurance in this population. Conclusions The MVe Fitness Chair™ is feasible for use in breast cancer survivors. It appears to promote similar improvements in muscular endurance when compared to traditional resistance training, but has several advantages over traditional resistance training, including cost, logistics, enjoyment, and ease of learning.
Energy-harvesting technology utilising mechanical energy sources is a promising approach for the sustainable, independent, and permanent operation of a variety of flexible electronics. A new concept of a fully-flexible light-emitting system, self-powered by a high-performance piezoelectric thin-film energy harvester has been first established by manipulating highly-robust, flexible, vertically structured light emitting diodes (f-VLEDs). The f-VLEDs fabricated by anisotropic conductive film bonding and entire wafer etching show stable and durable performances during periodic mechanical deformations. A high-output energy harvester capable of generating up to 140 V and 10 μA can be fabricated via laser lift-off (LLO) process widely used in industries, in a safe and robust manner. In particular, this LLO process is of great benefit for the fabrication of mechanically stable, flexible piezoelectric devices, without causing any degradation of piezoelectric properties. In this process, self-powered all-flexible electronic system with light emittance can be spontaneously achieved by the electricity produced from flexible thin-film generator by applying slight biomechanical energy without any externally applied energy storage. This conceptual technology of self-powering based on the conversion of mechanical energy to electrical energy can open a facile and robust avenue for diverse, self-powered, bio-implantable applications, as well as commercial display applications.
Rodents are frequently used to model damage and diseases of the central nervous system (CNS) that lead to functional deficits. Impaired locomotor function is currently evaluated by using scoring systems or biomechanical measures. These methods often suffer from limitations such as subjectivity, nonlinearity and low sensitivity, or focus on a few very restricted aspects of movement. Thus, full quantitative profiles of motor deficits after CNS damage are lacking. Here we report the detailed characterization of locomotor impairments after applying common forms of CNS damage in rodents. We obtained many objective and quantitative readouts from rats with either spinal cord injuries or strokes and from transgenic mice (Epha4−/−) during skilled walking, overground walking, wading and swimming, resulting in model-specific locomotor profiles. Our testing and analysis method enables comprehensive assessment of locomotor function in rodents and has broad application in various fields of life science research.
This paper describes dynamic modeling and simulation results of a small wind–fuel cell hybrid energy system. The system consists of a 400 W wind turbine, a proton exchange membrane fuel cell (PEMFC), ultracapacitors, an electrolyzer, and a power converter. The output fluctuation of the wind turbine due to wind speed variation is reduced using a fuel cell stack. The load is supplied from the wind turbine with a fuel cell working in parallel. Excess wind energy when available is converted to hydrogen using an electrolyzer for later use in the fuel cell. Ultracapacitors and a power converter unit are proposed to minimize voltage fluctuations in the system and generate AC voltage. Dynamic modeling of various components of this small isolated system is presented. Dynamic aspects of temperature variation and double layer capacitance of the fuel cell are also included. PID type controllers are used to control the fuel cell system. SIMULINKTM is used for the simulation of this highly nonlinear hybrid energy system. System dynamics are studied to determine the voltage variation throughout the system. Transient responses of the system to step changes in the load current and wind speed in a number of possible situations are presented. Analysis of simulation results and limitations of the wind–fuel cell hybrid energy system are discussed. The voltage variation at the output was found to be within the acceptable range. The proposed system does not need conventional battery storage. It may be used for off-grid power generation in remote communities.
Synthesis of LiCo1−x Ni x O2 by soft chemistry leads to a “new” material, which is more reactive and has a different morphology from oxide prepared by the direct solid-state method. The preparation of material by soft chemistry consists in a coprecipitation of powders, followed by a thermal treatment. This method allows a better control of structure, morphology and specific surface area (S w). This one is directly linked to the manganese presence which can increase it by a factor 10. Concerning the morphology, the presence of manganese in sample leads to an oxide network favorable for a good lithium intercalation.
Antifluorite-type materials, Li5+x Fe1−x Co x O4, were prepared and studied as a cathode for use in a lithium secondary battery. During the first charge process, the structure undergoes a phase change as the removal of lithium progresses. The original antifluorite structure is almost completely lost when 1.5 equivalents of lithium are deintercalated from the structure, as in the case of Li5FeO4. This tendency was less obvious in cobalt-doped samples, and 2.1 equivalents of lithium could be removed before the original lattice disappeared. Cobalt doping helps to maintain the original lattice configuration and enhances cycling stability. The Mössbauer spectra suggest that the electrons of oxygen atoms play a role in addition to those of iron. A 1.3 equivalents of lithium could be reversibly deintercalated from Li5.6Fe0.4Co0.6O4, which corresponds to 220mAhg−1.
Li3VO4 has been deemed as a promising anode material owing to its high theoretical capacity (592 mA h g−1), superior ionic conductivity, and zero strain during charge and discharge process. Nevertheless, its electronic conductivity is low, which has led to an electrochemical performance unfavorable for practical application. In this work, Fe doped Li3VO4 samples have been synthesized via freeze-drying and heating-treatment procedures. The obtained samples of Li3V(1-x)FexO4-δ (x = 0, 0.005, 0.01, 0.02) show a slight lattice expansion with an increase in Fe content. When evaluated for lithium storage capacity, Fe doped Li3VO4 samples exhibited an enhanced electrochemical performance relative to those undoped parent, as represented by an excellent rate capability (213 mA h g−1 at 2000 mA g−1), and good cyclic stability (a stable Coulombic efficiency of 98 ± 1% after initial three cycles at 100 mA g−1) for Li3V0.99Fe0.01O4-δ. The reasons for these performance improvements are ascribed to the increased electronic conductivity originated from the creation of oxygen vacancy, reduced bandgap, and a rapid Li+ ion diffusion process as revealed by X-ray photoelectron spectrum, O K-edge X-ray absorption near edge structure analysis, UV–vis spectroscopy, and electrochemical impedance spectroscopy. The present work provides some hints for designing and synthesizing Li3VO4 based anode materials with superior electrochemical performance.
Redox-flow batteries with organic-based electrolytes hold many advantages over conventional-flow batteries. Here the authors report a high-performance flow battery based on alloxazine, an aqueous-stable and soluble redox-active organic molecule resembling the backbone structure of vitamin B2.
Although intensive efforts have been made during the past decades, development of an anode material with high specific capacity and stable cycling performance for lithium-ion batteries (LIBs) using a cost-effective preparation method still remains challenging. Herein, we report a polyaniline (PANI)-coated mechanochemically synthesized SnO2/graphene (SG) nanocomposite via in situ polymerization. PANI-coated nanocomposites are successfully prepared with different raw material mass ratios (aniline:SG, 0.15:1, 0.2:1, 0.25:1). The nanocomposite with initial aniline:SG mass ratio of 0.2:1 (20%PANI-SG) contains an optimal structure housing genuine PANI nanofibers as conductive bridges and a relatively high surface area of 158.5 m2 g−1; furthermore, it exhibits a stable cycling performance over 100 cycles at high current density (1000 mA g−1) with a specific capacity of more than twice that of the starting SG electrode at the 100th cycle. Additionally, this material achieved an outstanding cycling rate with current densities changing stepwise from 100 to 3000 mA g−1 and back, and exhibited a specific capacity of 467 mA h g−1 even at 2000 mA g−1. In terms of the electrochemical stability, rate capability and cost-effective preparation process, the PANI-SG nanocomposite is a viable anode material for next-generation high-power and high-energy LIBs.