batterydata/paper-abstracts huggingface dataset:
In order to use LiMn2O4 as a cathode material of lithium-secondary battery for an electric vehicle (EV), its rate capability should be improved. To enhance the rate capability of LiMn2O4 in this work, the surface of LiMn2O4 particle was coated with LiCoO2 by a sol–gel method. Because LiCoO2 has a higher electric conductivity than LiMn2O4, it is possible to improve the rate capability of LiMn2O4. After the surface coating, LiCoO2-coated LiMn2O4 showed a higher discharge capacity of 120mAh/g than as-received LiMn2O4 (115mAh/g) because LiCoO2 has a higher capacity than LiMn2O4. The rate capability of the coated LiMn2O4 improved significantly. While as-received LiMn2O4 maintained only 50% of its maximum capacity at a 20C rate (2400mA/g), the LiCoO2-coated LiMn2O4 maintained more than 80% of maximum capacity. LiCoO2-coated LiMn2O4 with 3wt.% conducting agent (acetylene black) showed the higher rate capability than as-received LiMn2O4 with 20wt.% conducting agent. From electrochemical impedance spectroscopy (EIS) result that the first and second semicircles of coated LiMn2O4 were reduced, the improvement of rate capability is attributed to a decrease of passivation film that acts as an electronic insulating layer and a reduced inter-particle contact resistance. Accordingly, It is proposed that the surface coating of LiMn2O4 with LiCoO2 improve the rate capability as well as the specific and volumetric energy density due to the decrease of conducting agent.
The changes in structure, gaseous phase hydrogen storage, and electrochemical properties due to the incorporation of Y in the alloy formula have been studied on two series of AB2 alloys, with an originally C14- (relatively higher Cr-content) and a C15- (relatively higher Co-content) predominated microstructure, respectively. In each series, 1–4 at.% of Y was added to the designed formula and partially replaced Zr. A majority of the added Y went into the secondary phases, such as YNi, (Y, Sn)-rich, and Y2O3, and only a small amount being found in the main AB2 phase. The lattice constants and the unit cell volume decreased due to the reduction in Zr-content. The C15 phase abundances of the Y-containing alloys were higher than those of the Y-free alloys in both series. As the Y-content increased, the gaseous phase hydrogen storage capacity measured at 30 °C decreased in the high-Cr series and increased in the high-Co series. Both the hydrogen mid-point pressures and the electrochemical discharge capacities of the Y-containing alloys were lower than those in the Y-free alloys in both series. Both the activation and high-rate dischargeability (HRD) improved with the increase in Y-content. The −40 °C resistance was substantially reduced with the incorporation of Y in both series.
Composite electrodes of amorphous vanadium pentoxide/carbon/ceramic filler were prepared by mixing vanadium oxide hydrosol, acetone, carbon and ceramic fillers, and by extension on aluminum foil. High rate charge/discharge property of the composite electrode was examined, and the effect of fillers was discussed. The composite electrode had a porous structure, in which pores were 0.5–3μm in diameter and penetrated through the composite. The composite electrode showed a large capacity of 98mAh/g-electrode at a high current density of 17.2mA/cm2 (270A/g-electrode). The relation between discharge capacity and current density was calculated by solving the simplified diffusion equation. The apparent diffusion coefficient of lithium ion in the composite electrode was found to be 10 times larger than that of electrode without fillers.
The recycling of Waste Electrical and Electronic Equipment (WEEE) has attracted a notable amount of interest during the last few decades due to the high metal concentrations and substantial increase in the growth rate of WEEE. In addition, higher recovery and recycling rates required by the European Union demand more comprehensive treatment of WEEE. However, complex product design and the presence of harmful substances together with low concentrations of special metals present challenges for processing. This study examines the effect of mechanical treatment of mobile phones on metal concentrations in the printed circuit assembly (PCA) fraction compared to manual dismantling. The designed mechanical treatment process including crushing, sieving, magnetic-, eddy current- and sensor-based separation was able to separate plastics, ferrous metals, PCA and stainless steel for further treatment. The process separated PCA with an efficiency of 85%. However, the quality of the separated PCAs was poor compared with “pure” manually dismantled PCAs. The primary crushing of mobile phones destroys PCAs thus resulting in the loss of especially precious metals used in the connector coatings and in the surface-mounted components. As a result, the theoretical value of the produced PCA fraction is only half compared to using manual dismantling. However, high labour costs in western countries and low capacity may hinder the feasibility of hand dismantling.
Nano-Mn3O4 +PbO2 composite electrode materials with different compositions are prepared by anodic composite electrodeposition in Pb2+ plating solution containing suspended nano-Mn3O4 particles (40–60nm). The particles are synthesized via one-step homogeneous precipitation at low temperature. The composite materials are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) analyses. The results indicate that the composite composed of γ-Mn3O4 and β-PbO2 is porous and quasi three-dimensional (3D), and its maximum electrochemically effective area ratio (R F) is 72. The capacitance performance of the composite is determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge test. The composite shows a high specific capacitance up to 338Fg−1.
Submicron-sized LiNi1/3Co1/3Mn1/3O2 cathode materials were synthesized using a simple self-propagating solid-state metathesis method with the help of ball milling and the following calcination. A mixture of Li(ac)·2H2O, Ni(ac)2·4H2O, Co(ac)2·4H2O, Mn(ac)2·4H2O (ac=acetate) and excess H2C2O4·2H2O was used as starting material without any solvent. XRD analyses indicate that the LiNi1/3Co1/3Mn1/3O2 materials were formed with typical hexagonal structure. The FESEM images show that the primary particle size of the LiNi1/3Co1/3Mn1/3O2 materials gradually increases from about 100nm at 700°C to 200–500nm at 950°C with increasing calcination temperature. Among the synthesized materials, the LiNi1/3Co1/3Mn1/3O2 material calcined at 900°C exhibits excellent electrochemical performance. The steady discharge capacities of the material cycled at 1C (160mAg−1) rate are at about 140mAhg−1 after 100cycles in the voltage range 3–4.5V (versus Li+/Li) and the capacity retention is about 87% at the 350th cycle.
A large size 80V bipolar lead acid battery was constructed and tested successfully with a drive cycle especially developed for a HEV. The bipolar battery was made using the bipolar plate developed at TNO and an optimised paste developed by Centurion. An empirical model was derived for calculating the Ragone plot from the results from a small size 12V bipolar lead–acid battery. This resulted in a specific power of 340W/kg for the 80V module. The Ragone plot was calculated at t=5 and t=10s after the discharge started for current densities varying from 0.02 to 1.2A/cm2. A further development of the bipolar lead–acid battery will result in a specific power of 500W/kg or more. From the economic analysis we estimate that the price of this high power battery will be in the order of 500 US$/kWh. This price is substantially lower than for comparable high power battery systems. This makes it an acceptable candidate future for HEV.
Density-based clustering relies on the idea of associating groups with regions of the sample space characterized by high density of the probability distribution underlying the observations. While this approach to cluster analysis exhibits some desirable properties, its use is necessarily limited to continuous data only. The present contribution proposes a simple but working way to circumvent this problem, based on the identification of continuous components underlying the non-continuous variables. The basic idea is explored in a number of variants applied to simulated data, confirming the practical effectiveness of the technique and leading to recommendations for its practical usage. Some illustrations using real data are also presented.
MnII–glycine complex in slightly alkaline solution is oxidized at a less positive potential (+0.25 to +0.6 V vs. Ag∣AgCl) where free Mn2+ ion is not oxidizable, leading to the formation of a thin uniform film containing MnIII oxide. The film prepared by continuous cyclic scans in the potential region between +0.2 and +0.6 V exhibited an electron spin resonance (ESR) peak attributed to MnII(H2O)6, but this resonance peak disappeared when the lowest potential was shifted to 0 V. From the electrochemical quartz crystal microbalance (EQCM) measurements, the film deposited anodically can be represented as Mn2 IIIO6[MnII(H2O)6]3 which corresponds to a structure where MnII in Mn5O6 (Mn2 IIIMn3 IIO6) is not bound to the oxygen atom in the MnIIIO network but is coordinated with water molecules. The MnII(H2O)6 in the film was suggested to be released during the reduction of the oxide matrix and oxidized to form the MnIIIO bond at more positive potentials than +0.6 V.
Three flow designs were operated in a 3-cell 1 kW class all vanadium mixed acid redox flow battery. The influence of electrode surface area and flow rate on the coulombic, voltage, and energy efficiency and the pressure drop in the flow circuit will be discussed and correlated to the flow design. Material cost associated with each flow design will also be discussed.
Demotivation is an issue, which has been recently the focus of attention in the field of second language (L2) learning and teaching [8] (Muhonen, 2004). Since the present researchers failed to find any studies conducted in this area in Iran, this study was carried out to investigate Iranian high school teachers’ and students’ ideas about demotivating factors with regard to practicing the speaking skill. To achieve this goal, 312 high school students and 92 high school teachers of English were interviewed. Then the interviews were thematically analysed. The findings along with the researchers’ reviews of the related literature were used to develop a questionnaire to explore Iranian L2 students’ and teachers’ perceptions of the factors which decrease students’ motivation to improve their L2 speaking ability. This questionnaire was administered to 150 Iranian male and 150 female EFL learners and 40 male and 40 female teachers. To analyse the data, the researchers employed principal components analysis with varimax rotation. The factors which emerged were negative attitude toward learning L2, teacher's inadequate competence and performance, lack of technological facilities in classroom, lack of adequate teaching materials, unfavourable classroom environment, and insufficient opportunities for speaking practice. The interpretable factor structure, the high loadings of items on the abovementioned factors, and the relatively high amount of variance accounted for by this factor structure show that the questionnaire is a valid instrument to be used in similar studies. Also, the internal consistency estimates of the factors show that they enjoy high reliability.
Aqueous, ethanolic and ethyl acetate extracts of the bark and leaves of five South African Erythrina species Erythrina caffra, Erythrina humeana, Erythrina latissima, Erythrina lysistemon and Erythrina zeyheri were screened for prostaglandin synthesis-inhibitory and anti-bacterial activity. The bark generally displayed higher activity than the leaves in both bioassays. The highest cyclooxygenase inhibiting activity and anti-bacterial activity was recorded for the ethanol and ethyl acetate bark extracts of E. caffra, E. latissima and E. lysistemon. An anti-bacterial compound, 4′,5,7-trihydroxy-6-prenylisoflavone, was isolated by bioassay-guided fractionation from bark of E. lysistemon.
A novel layered P2–K~2/3[Ni1/3Mn2/3]O2 (K0·64Na0·04[Ni1/3Mn2/3]O2, KNMO) is presented as a high-performance cathode for K+-ion batteries. KNMO is prepared via an electrochemical ion-exchange of P2–Na0.64[Ni1/3Mn2/3]O2 (NNMO). During 50 charge/discharge (C/D) cycles within a P2-phase range, NNMO gradually turns to KNMO and finally reaches KNMO through a biphasic state. The as-prepared KNMO shows a P2–O2 transition at 4.65 V vs. K/K+, which implies that K+-preference in the prismatic sites of KNMO leads to the formation of O2-phases at higher voltages than that predicted from NNMO. Thanks to the retardation of the P2–O2 transition and fast diffusion during K+ extraction (0.57 × 10−11 cm2 s−1), KNMO can be quickly charged within the P2-phase region without a significant loss in discharge capacities. For example, comparable capacities of 82 and 75 mAh·g−1 during discharge (0.5C) are obtained after charging at 0.5 and 15C (2580 mA g−1), respectively. This behavior is contrasted with a significant reduction in capacities when cycled at the same C/D rates or when cycled at C/D rates of 0.5/15C, respectively. KNMO also shows excellent cyclability during fast charging, retaining a reversible capacity of 73 mAh·g−1 after 200C/D cycles (0.01 mAh·g−1·cycle−1).
An electrochemical kinetic model (EKM) is developed, describing the electrochemical hydrogen storage in hydride-forming materials under equilibrium conditions. This model is based on first principles of electrochemical reaction kinetics and statistical thermodynamics and describes the complex, multi-stage, electrochemical (de)hydrogenation process. A complete set of equations have been derived, describing the equilibrium hydrogen partial pressure and equilibrium electrode potential as a function of hydrogen content in both solid-solution and two-phase coexistence regions. The EKM has been applied to simulate the isotherms of thin film Pd electrodes of various thicknesses. Good agreement between experiment and theory is found in all cases. Relevant energy and kinetic parameters are obtained from the simulations.
Reduced graphene oxide (RGO)-carbon nanotubes (CNTs) composite films were successfully fabricated by electrophoretic deposition and used as electrode materials for electrochemical supercapacitors. RGO was obtained by microwave-assisted reduction of graphene oxide dispersion in acidic aqueous solution using a microwave synthesis system. The electrochemical performances of the films were analyzed through cyclic voltammetry and chronopotentiometry tests. The results showed that as compared with pure RGO and CNTs, RGO–CNTs composite with 40% CNTs exhibited an optimal electrochemical capacitance of 87F/g due to a synergistic effect of RGO and CNTs.
In this work, a new electrochemical method based on fast Fourier transformation continuous cyclic voltammetry (FFTCCV) technique is introduced for electrodepositing of nano-structured PbO2. During the electrodepositing, a special potential waveform, consisted of a potential step and a potential ramp, was continuously applied on a Pt disk electrode. Various parameters such as potential scan rate, and potential of step were optimized to obtain higher capacity and stability for the formed lead oxide layer. Depend on the potential waveform condition, the morphology and connectivity of the oxide film was changed. The energy storage ability of the prepared lead acid batteries shows a close relation with the morphology of cathode materials. Maximum current efficiency was observed when the potential scan rate reaches to 5Vs−1. The electrode surface was characterized by SEM. The results showed the high surface area as well as high connectivity between particles resulted at optimum scan rate. Analysis of FFTCCV data of obtained PbO2 in H2SO4 revealed that the electrocatalytic properties, and as well stability of PbO2 layer amplified by increasing scan rates up to an optimum value. In addition, a larger over potential for oxygen evolution reaction was also observed for the electrodes by application of this method.
The clinical study of crossed aphasia in dextrals (CAD) may shed light on the discreteness and modularity of several cognitive functions, such as language, gestures and visual spatial abilities, with respect to hemispheric lateralisation. Since 1975 over 180 cases have been described, employing, however, different criteria of assessment and classification. The purpose of this paper is to review them and to propose a set of diagnostic criteria that may be useful to single out a series of reliable CAD cases on which research can be safely carried out. A detailed analysis of such series is dealt with in terms of a number of characteristics concerning both the language disorder and the associated nonverbal cognitive impairments.
Extraordinary declines in the cost of photovoltaic systems (PV), combined with a growing range of energy efficient consumer technologies (EE), has driven significant deployment of these two options in many jurisdictions. This deployment has proven to be a key way to mitigate the risks of catastrophic climate change. However, existing retail electricity arrangements can create mixed incentives for households contemplating investing in both PV and EE. This is caused by net metering arrangements that value self-consumption of PV generation far more than PV exports to the grid. This means that falling household demand due to EE may significantly reduce the financial value of PV. Meanwhile, the continuous cost decline of battery storage systems (BS) has encouraged more PV owners to consider storing PV exports to maximise self-consumption. However, there has been little research on whether the addition of BS could reduce barriers to the combined uptake of PV and EE. In this paper, real PV generation and electricity consumption data is used from numerous households in Sydney (Australia), together with a battery cyclelife model, to assess the financial outcomes of combining PV, EE and BS. The results indicate that EE can reduce PV system revenue, that adding BS to a combination of PV and EE generally increases PV revenue, that BS costs are still high for this residential application, and that the uptake of EE can result in deeper BS cycling which reduces the battery lifetime.
The impedance of Li-ion battery using a Li4Ti5O12 (LTO) anode for high-power applications was measured at various depths of discharge and temperatures during charge–discharge cycles. The measured impedance was interpreted with an equivalent circuit made up of anode and cathode, in which the cathode component was composed of two particle size factors. The values obtained for equivalent circuit elements by modeling were in good agreement with the results measured by other techniques, and indicated that the capacity fade of this Li-ion battery due to cycling is mainly caused by the increase of interfacial resistance and a decrease in the capacity of the LiCoO2 cathode. These results suggest that the cyclability of this LIB was improved by using an LTO anode, and show the validity of the equivalent circuit for interpreting the causes of capacity fade.
This study investigated the surface and electrochemical properties of carbon cloth electrodes surface-modified by using atmospheric pressure plasma jets (APPJs) for applications involving microbial fuel cells (MFCs). APPJ treatment made the carbon cloth highly hydrophilic and did not introduce any observable cracks or flaws. MFCs configured with APPJ-treated carbon cloth electrodes exhibited electrochemical performance (maximum power density of 7.56 mW m−2) superior to that of MFCs configured with untreated carbon cloth electrodes (maximum power density of 2.38 mW m−2). This boost in performance can be attributed to the formation of abundant carboxyl and ammonium functional groups on the surface of APPJ-treated carbon cloth, which promoted the formation of anodic biofilms and the adhesion of bacteria, while facilitating the transfer of electrons from the bacteria to the electrodes. APPJ surface modification is non-toxic and environmentally friendly (no exogenous chemicals are required), which is particularly beneficial as the introduction of toxins might otherwise inhibit bacterial growth and metabolism. The APPJ surface modification process is rapid, cost-effective, and applicable to substrates covering a large area, making it ideal for the fabrication of large-scale MFCs and bioelectrochemical bioenergy devices.
Amorphous and crystalline FePO4 were synthesized by annealing the precursor aqueous solution with P2O5 and iron powder in air. Although planetary ball milling is effective for reducing the synthetic time, it was confirmed that 15 days were sufficient reaction time, even at room temperature, to bring the same result without mixing. Annealing at over 500°C in air resulted in trigonal FePO4 with a P321 space group. Both amorphous and crystalline FePO4 have a corner-shared matrix, and they showed similarly good capacity, not only for Li but also for Na anodes.
We have synthesized a composite of surfactant assisted polyaniline nanofibres and graphene oxide (SPGO) followed by reduction to prepare surfactant assisted polyaniline nanofibres-reduced graphene oxide (SPG) composite. The performance of the synthesized composite has been compared with the SPGO, PANI and reduced graphene oxide (rGO). The prepared samples have been characterized by Field effect scanning electron microscopy (FESEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) techniques. The electrodes prepared from these samples have been tested for their electrochemical performances using cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedence spectroscopy (EIS), in a two electrode configuration. The CV results revealed that the SPG cell has higher voltammetric current as compared to SPGO, PANI and rGO cells leading to better capacitive nature. From charge discharge studies, the SPG cell exhibits maximum specific capacitance of 444Fg−1 at 0.6 Ag−1 with good retention after 2000 charge discharge cycles. The specific energy and power density of the SPG cell is observed to be 13.36Whkg−1 and 1.03kWkg−1, respectively, which is significantly large as compared to SPGO, PANI and rGO cells. The EIS studies showed enhanced rate performance of SPG cell as compared to the rGO and PANI cell which is in agreement with the CV results. These results make it a promising candidate for supercapacitor applications.
Enhancing the mass transport from the flow field side to the membrane side without sacrificing the active surface area is a critical strategy for the design of electrodes in flow-field structured vanadium redox flow batteries (VRFBs). In this work, we design and prepare a novel porous electrode with a gradient distribution in pores, enabling a gradual decrease in permeability but an increase in active surface areas from the flow field side to the membrane side. This design not only increases the electrode utilization due to the enhanced mass transport near the flow field side, but also avoids the loss of active surface area near the membrane side. Numerical modeling results show that compared to the conventional electrode design, the gradient electrode design can promote the uniform distribution of local reaction current density and overpotential, leading to a lower charge voltage and higher discharge voltage. Experimental results show that at the current density of 240 mA cm−2, the battery with the gradient electrode design delivers a 69% higher discharge capacity than that with the conventional electrode design, demonstrating the superiority of the gradient electrode design strategy.