batterydata/paper-abstracts huggingface dataset:
In analyses of the scanning vibrating electrode technique (SVET), the conductivity of the electrolyte solution near the specimen is usually assumed to be uniform over space and constant over time when calculating the current density. These assumptions may be inadequate in practice, and non-uniformity due to electrolysis should not be ignored. To overcome these limitations, ion transport is considered in a dilute solution. To describe the ion concentration and electric field change close to the specimen surface, a model is used that employs the Nernst–Planck equation and the electro-neutral condition. A finite difference method is used to solve the resulting time-dependent axisymmetric problem. The computational results show good agreement with the experimental data obtained by SVET. It is also found that the electric potential gradient reduces to one-tenth of the initial value and of the result predicted by the conventional model with uniform conductivity.
A new cobalt free LiFeO2–Li2MnO3 based solid solution with a composition of Li(Li0.23Mn0.47Fe0.2Ni0.1)O2 is developed to obtain high capacity and better cycling stability. A new citric acid assisted sol–gel process including three-step of “preparation of wet gel—formation of spray-dried gel—annealing at high temperature” is proposed. The results show that uniform Li(Li0.23Mn0.47Fe0.2Ni0.1)O2 solid solution with pure hexagonal phase (or monoclinic phase) can be successfully prepared even at low temperature of 600 °C. Increasing the annealing temperature can improve the crystallization and cation-ordering of Li(Li0.23Mn0.47Fe0.2Ni0.1)O2, but severe agglomeration to form large size secondary particles (1–10 μm) over 750 °C leads to the decreased capacity. The sample annealed at optimized temperature of 700 °C shows uniform fine well-crystallized particles with 100–200 nm diameters, high capacity of 277.4 mAh g−1 at 10 mA g−1 (0.04C) and better cycling stability at different rate. It presents a capacity of 188 mAh g−1 at 75 mA g−1 (0.3C) and 90.4% capacity retention after charge–discharged 100 cycles.
Interfacial reactions of Sn during initial cycling in 1M LiPF6/EC:DMC (1:1) were studied by characterizing the surface species formed on thin film electrodes of Sn, prepared with a pulsed laser deposition, using ex-situ ATR FTIR spectroscopy and microscopy. FTIR analyses indicated that at high voltage region above 1.0V vs. Li/Li+ the surface of Sn electrode was covered by PF-containing inorganic species probably by the interfacial reactions between Sn and PF6 − anions. With charging to 0.63V low amounted organic species with carboxylate metal salt and alkyl functionalities appeared, due to the reductive decomposition of organic solvents. The organic surface species however were destroyed upon a deep charge to 0.1V and reproduced on the subsequent discharge process, whereas P–F containing inorganic species remained preserved. No sustainment of organic surface species but the stable passivation of Sn surface by PF-containing species during initial cycling are believed to cause unstable interfacial structure and the possibility of reduced utilization of active Sn, respectively, resulting in the large initial irreversible capacity loss.
Energy management is key in prolonging the lifetime of an energy harvesting Internet of Things (IoT) device with rechargeable batteries. Such an IoT device is required to fulfill its main functionalities, i.e., information sensing and dissemination at an acceptable rate, while keeping the probability that the node first becomes non-operational, i.e., the battery level hits zero the first time within a given finite time horizon, below a desired level. Assuming a finite-state Continuous-Time Markov Chain (CTMC) model for the Energy Harvesting Process (EHP), we propose a risk-theoretic Markov fluid queue model for the computation of first battery outage probabilities in a given finite time horizon. The proposed model enables the performance evaluation of a wide spectrum of energy management policies including those with sensing rates depending on the instantaneous battery level and/or the state of the energy harvesting process. Moreover, an engineering methodology is proposed by which optimal threshold-based adaptive sensing policies are obtained that maximize the information sensing rate of the IoT device while meeting a Quality of Service (QoS) constraint given in terms of first battery outage probabilities. Numerical results are presented for the validation of the analytical model and also the proposed engineering methodology, using a two-state CTMC-based EHP.
This paper presents a control power supply (CPS) design which is used to feed power to the subsystems of a power converter. The CPS design presented here maintains a constant 24Vdc output even over a wide (90Vrms to 270Vrms) ac voltage variation at its input for a High Power Converter (HPC). The circuit design and closed loop control design of such a CPS are presented. During starting, the power supply to the control circuitry of the CPS in turn is obtained using a separate start-up power supply. The various design issues and details of the on-board power supply and start-up power circuit to ensure the reliable start-up and shut down of the CPS are analyzed. The CPS was tested for wide input voltage range (vin) and the performance validates the design. The CPS has also been tested for an input side voltage sag and its performance allows the HPC to meet the low voltage ride-through requirements.
The effects of graphene and C coating modifications on electrochemical performance of silicon nanoparticle (SiNP)/graphene composite anode were investigated. Graphene with varying sheet sizes (238, 160 and 113 nm) were used as an anode material where a cycling performance dependence on the sheet size (edge sites and sheet disorder) was observed. Temperature-dependent N doping of graphene resulted in graphene with N (5.97% w/w) presenting three binding configurations: 72.1% pyridinic N, 22.4% pyrrolic N and 5.5% graphitic N. The nitrided graphene displayed improved cycling capacity and minimized performance decay, principally due to the pyridinic N. Galvanostatic cycling using increasing current density rates (500–2500 mA g−1) of SiNP composites with C coating/deposition showed improvements in both capacity retention and rate performance. A polyacrylonitrile (PAN)-based coating scheme was used to produce a N-containing (2.20%) C coating which displayed the best high performance improvements, attributable to the minimization of direct solid-electrolyte interphase (SEI) formation and improvement in the conduction path. Optimization of the methods to achieve the best modification characteristics might enable performance improvements that maximize the capabilities of the materials.
Co3O4 microspheres were synthesized in mass production by a simple hydrothermal treatment. One micrometer-sized spherical particles with well-crystallization could be obtained by XRD and SEM. Higher specific surface area (93.4m2 g−1) and larger pore volume (78.4cm3 g−1) by BET measurements offered more interfacial bondings for extra sites of Li+ insertion, which resulted in the anomalous large initial irreversible capacity and capacity cycling loss due to SEI film formation. The capacity retention of Co3O4 microspheres involved first forming acted as Li-ion anode material is almost above 90% from 12th cycle and it retain lithium storage capacity of 550.2mAhg−1 after 25 cycles, which show good long-life stability. The electrochemical impedance spectroscopy (EIS) tests before and after cyclic voltammetry measurements and charge–discharge experiments were carried out and the corresponding D Li values were also calculated. The relationship of the ac impedance spectra and the cycling behaviors was discussed. It is found that the decrease of capacity results from the larger Li+ charge-transfer impedance and the lower lithium-diffusion processes on cycling, which is in very good agreement with the electrochemical behaviors of Co3O4 electrode.
Electrochemical capacitors (ECs), also known as pseudocapacitors or supercapacitors (SCs), is receiving great attention for its potential applications in electric and hybrid electric vehicles because of their ability to store energy, alongside with the advantage of delivering the stored energy much more rapidly than batteries, namely power density. To become primary devices for power supply, supercapacitors must be developed further to improve their ability to deliver high energy and power simultaneously. In this concern, a lot of effort is devoted to the investigation of pseudocapacitive transition-metal-based oxides/hydroxides such as ruthenium oxide, manganese oxide, cobalt oxide, nickel oxide, cobalt hydroxide, nickel hydroxide, and mixed metal oxides/hydroxides such as nickel cobaltite and nickel–cobalt oxy-hydroxides. This is mainly due to the fact that they can produce much higher specific capacitances than typical carbon-based electric double-layer capacitors and electronically conducting polymers. This review presents supercapacitor performance data of metal oxide thin film electrodes by microwave-assisted as an inexpensive, quick and versatile technique. Supercapacitors have established the specific capacitance (Cs) principles, therefore, it is likely that metal oxide films will continue to play a major role in supercapacitor technology and are expected to considerably increase the capabilities of these devices in near future.
We report on sulfur-functionalized ordered mesoporous carbons aimed for lithium-sulfur battery electrode applications with improved charge capacity retention. The carbons were obtained by a hard-template strategy using a mixture of furfuryl alcohol and furfuryl mercaptan. For the application as electrode material in lithium-sulfur batteries, the carbons were additionally loaded with sulfur following a traditional melt-diffusion approach. It was found that the sulfur interacts stronger with the sulfur-functionalized carbon matrix than with the non-functionalized material. Electrodes showed very high capacity in the second discharge-charge cycle amounting to approximately 1500, 1200 and 1400 mAh/g (sulfur) for carbon materials with no, medium and high degrees of sulfur functionalization, respectively. More importantly, the sulfur-functionalization of the carbon was found to increase the capacity retention after 50 discharge-charge cycles by 8 and 5% for the carbons with medium and high degrees of sulfur-functionalization, respectively, compared to carbon with no sulfur-functionalization. We attribute this significant improvement to the presence of covalently bound sulfur groups at the internal surface of the functionalized carbon providing efficient anchoring sites for catenation to the sulfur loaded into the pores of the carbons and provide experimental support for this in the form of results from cyclic voltammetry and X-ray photoelectron spectroscopy.
The effects of excess lithium and aluminum doping in nickel oxide were investigated in an attempt to improve electrochemical properties of the layered LiNiO2. Li1+x NiO2 (x=0–0.02) and LiAl y Ni1−y O2 (y=0–0.3) powders were synthesized by a sol–gel method using adipic acid as a chelating agent. The electrochemical properties of the synthesized materials were explored at room and high temperatures. Gas analysis during decomposition of gel precursors revealed that oxygen might play an important role in the synthesis of highly crystallized LiNiO2. Although the electrochemical test of the Al-doped samples showed a low initial discharge capacity of about 140 mAh g−1, the capacity loss with repeated cycling was very small at room temperature. Furthermore the fade in capacity of this cell at high temperature (50°C) was almost negligible. The Al-doping of the LiNiO2 cathode material was very effective in improving cycle performance at high temperature due to the enhanced stability of LiNiO2 structure.
Searching active and cost-effective bifunctional electrocatalysts for overall water splitting is a vital but challenging task towards clean and sustainable energy sources. Here, mixed metal phosphides of Ni2PCoP anchored on N-doped reduced graphene oxide (NiCoP/N-rGO) as efficient and earth-abundant electrocatalysts for water splitting are reported. The large active sites, synergism, and hybridization with N-doped rGO endow NiCoP/N-rGO electrocatalyst with outstanding oxygen evolution reaction activity that is better than benchmark RuO2 in alkaline electrolyte, as well as active hydrogen evolution reaction in acidic, neutral, and alkaline solution. NiCoP/N-rGO has further been employed as both anode and cathode in a two-electrode alkaline water electrolyzer towards overall water splitting, exhibiting advanced electrochemical performances with a low cell voltage of 1.57 V at a current density of 20 mA cm−2. Moreover, the overall water splitting in this two-electrode electrolyzer can be driven by a single-cell AA battery (nominal voltage of 1.5 V), making NiCoP/N-rGO as the promising efficient cost-effective catalysts for water electrolysis.
Characterization of materials for advanced lithium ion batteries (LIBs) represents an essential area of the contemporary energy storage technologies. The present work illustrates an electroanalytical framework for quantitative testing of liquid electrolytes for LIBs. The measurements explore a temperature range from 40 °C to sub-zero regimes, with a special focus on the electrolyte functions for low temperature applications. The test electrolytes include different combinations of ethylene, dimethyl, diethyl and ethyl methyl carbonate (EC, DMC, DEC and EMC, respectively) solvents, with LiClO4, Li bis(trifluoromethane)sulfonimide (LiTFSI) and LIBF4 salts. The experiments utilize the diagnostic features of electrochemical impedance spectroscopy (EIS), in combination with cyclic voltammetry (CV) and galvanostatic cycling. Temperature controlled measurements of two- and three-electrode EIS, coupled with CV, demonstrate how the electrolyte conductivity and electrochemical stability can be evaluated in a comprehensive approach. The compositions of the test electrolytes are optimized according to their temperature dependent ionic conductivities and their electrochemical windows. Two optimal electrolytes based on EC:EMC and EC:DMC:EMC mixtures are further examined for battery operations by galvanostatic cycling in a half-cell containing a Li4Ti5O12 anode. Consistent with the findings of the conductivity and electrochemical window measurements, the EC:EMC system exhibits superior performance in these half-cell experiments.
Novel hierarchical flower-like nickel sulfide assembled by nanoplates has been successfully synthesized via a template-free and one-step solvothermal method. The number of composed nanoplates can be tuned by adjusting the additive amounts of reactants. As comparative electrochemical performances are performed on, the sample with more nanoplates shows a higher specific capacitance and promising cycling stability. After 3000 cycles, a high specific capacitance of 778.8 F g−1 still maintains when the current density is 4 A g−1. These satisfactory electrochemical behaviours can be attributed to the hierarchical flower-like architecture, which supply more reactive sites for charge/discharge processes.
Here we report the evaluation of natrochalcite (Na[Cu2(OH)(H2O)(SO4)2]), an anionic layered structure [Cu2(OH)(H2O)(SO4)2]− charge-balanced by Na+, as an anode material for both Li- and Na-ion batteries. It delivers 224 mAh/g and 175 mAh/g in the first discharge in the Li+- and Na+-cells respectively, and decomposes to form amorphous matrixes during this step. In the subsequent charge, the original layered structure is unusually partially recrystallized back from the matrixes, resulting in 53 mAh/g and 35 mAh/g discharge capacities in the second discharge respectively. In subsequent cycling, Li+ in the electrolyte is found to replace the original Na+ during cycling in the Li+-cell and the electrode in the Li+-cell demonstrates better capacity retention rates than that in the Na+-cell, possibly due to Li+ being smaller than Na+ and thus decomposition-recrystallization cycles being more reversible during cycling in the Li+-cell.
The solubility of LaCl3 in acidic AlCl3–1-ethyl-3-methylimidazolium chloride (AlCl3–EMICl) ambient temperature melts at 298 K increases as the acidity of the melts increases. When LaCl3 was dissolved in the melt (molar fraction of AlCl3, N=0.667), Raman spectra of AlCl4 − and Al2Cl7 − anion were observed. From these results, the dissolution reaction in the acidic melts is thought to be: 3Al2Cl7 −+LaCl3⇄La(III)+6AlCl4 −. Electrochemical measurements and potentiostatic electrolysis were performed in various LaCl3 saturated AlCl3–EMICl melts. The electrodeposits obtained at more negative potential than −0.18 V versus Al(III)/Al in a LaCl3 saturated acidic melt (N=0.667) were pure aluminum metal. It was suggested that lanthanum metal electrodeposits at around −1.95 V in the LaCl3 saturated melt (N=0.667) after addition of excessive LiCl and 50 mmol kg−1 of SOCl2.
A number of genes located on chromosome 22q11–13, including catechol-O-methyltransferase (COMT), are potential schizophrenia susceptibility genes. Recently, the sulfotransferase-4A1 (Sult4A1) locus within chromosome 22q13 was reported to be linked to schizophrenia in a family TDT study. Sult4A1 is related to metabolism of monoamines, particularly dopamine and norepinephrine, both of which have been implicated in the pathophysiology of the psychopathology and cognitive dysfunction components of schizophrenia. An available, prospectively collected data base was interrogated to determine how three Sult4A1 SNPs: rs138060, rs138097, and rs138110, previously shown to be associated with schizophrenia might be associated with psychopathology, cognition, and quality of life in a sample of 86 Caucasian patients with schizophrenia or schizoaffective disorder. The majority of patients met criteria for treatment resistant schizophrenia and had been drug-free for one week or longer at the time of evaluation. The major findings were: 1) patients heterozygous (T/G) for rs138060 had significantly worse Brief Psychiatric Rating Scale (BPRS) Total and anxiety/depression sub-scale scores, and higher Scale for the Assessment of Positive Symptoms (SAPS) Total scores than G/G homozygous patients; and 2) patients heterozygous (A/G) for rs138097 demonstrated significantly worse performance on neuropsychological testing, specifically on tests of executive function and working memory, compared to patients homozygous for the G and A alleles. RS138110 was unrelated to psychopathology and cognition. These results provide the first evidence of how genetic variation in Sult4A1 may be related to clinical symptoms and cognitive function in schizophrenia, and permit future studies to attempt to replicate these potentially important findings.
ABSTRACT In order to investigate the influences of Mg–Al–B co-substitution on LiNi0.5Co0.2Mn0.3O2 material, the uniform and spherical doped Li[Ni0.5Co0.2Mn0.3]0.992Mg0.003Al0.003B0.002O2 material is successfully prepared through a simple solid state synthesis. X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) mapping, X-ray photoelectron spectroscopy (XPS) and electrochemical tests have been applied for material characterizations and electrochemical measurements. Through the result of XRD and the Rietveld refinements, Mg, Al and B atoms may be incorporated into the crystal lattice. Similarly, the results of EDX and XPS confirm the existence of Mg2+, Al3+ and B3+ in accordance with the chemical formula. The Mg–Al–B co-substitution LiNi0.5Co0.2Mn0.3O2 material shows excellent electrochemical performance, especially the superior cycling stability under high cutoff voltages. The Mg–Al–B co-substitution LiNi0.5Co0.2Mn0.3O2 material exhibits the higher capacity retentions of 83.8%, 84.9%, 83.2% and 80.4% than that of the bare one (71%, 62.5%, 40.9% and 25%) after 200 cycles at a cutoff voltage of 4.2, 4.3, 4.4 and 4.5V, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirm that the modification of Mg–Al–B co-substitution plays an important role in improving the electrochemical performance of the bare LiNi0.5Co0.2Mn0.3O2.
Li(NixMnyCo1−x−y)O2 (NMC) is considered as one of the most promising cathode materials for Li-ion batteries. Highly textured LiNi0.5Mn0.3Co0.2O2 (NMC532) thin films with well dispersed Au nanoparticles (~ 5 nm in average diameter) were deposited by pulsed laser deposition. Microstructure studies reveal the epitaxial nature of the Au nanoparticles and NMC matrix, and their lattice matching relationships. The Au nanoparticles are uniformly distributed and form faceted interfaces with NMC matrix. NMC with 2 at.% Au shows the highest volumetric capacity, best initial columbic efficiency, highest cycling performance, best rate capability and highest capacity retention among all the samples, due to alteration of chemical environment of transition metal while keeping high crystallinity. Moreover, the electrochemical impedance spectroscopy data shows that the incorporation of the Au nanoparticles also reduces charge transfer resistance compared to the pure NMC. The results suggest that appropriate Au nanoparticle incorporation enhances the volumetric capacity and promotes the charge transfer process, and thus could lead to enhanced battery performance.
An experimental analysis of platinum utilization in a DMFC cathode is performed. The chief objective of this work is to elucidate the effect of Nafion and polytetrafluoroethylene (PTFE) on platinum utilization values on the cathode. Polarization curves indicate that the performance of a DMFC is sensitive to the Carbon/Nafion (C/N) and Nafion:PTFE (N/P) ratio in the catalyst layer. Our analysis shows that supported Pt/C catalysts have a much higher platinum utilization value than unsupported catalysts. Platinum utilization is a maximum at a C/N ratio of 2.5 and at a N/P ratio of six. Platinum utilization is more sensitive to the Nafion content in the catalyst layer than the Teflon content.
This study was designed to investigate the effects of inquiry chemical experiment in chemistry teaching in promoting preservice teachers’ critical thinking dispositions. A pretest and posttest experimental design with a comparison group was employed to validate the effectiveness of the proposed approach. Ten chemical experiments were selected, and 42 chemical preservice teachers aged at 19-22 voluntarily participated in the research. The California Critical Thinking Disposition Inventory (CCTDI) was used to assess the level of preservice teachers’ critical thinking skills. The CCTDI post scores of the preservice teachers in chemical inquiry experiments training had improved, which showed that the inquiry chemical experiment has certain promoter action to the preservice teachers’ critical thinking disposition. However, the preservice teachers did not achieve high levels of Critical Thinking (CT) in either the inquiry or the traditional approaches, nor did they score high or differ significantly on subscales except analyticity. The findings indicated that inquiry chemical experiment encouraged preservice teachers’ ability to think critically, demand the application of reason and evidence and incline to anticipate consequences.
Multimorbidity is highly prevalent in older adults, both those with and without cancer, and is associated with an increased risk of mortality. The aim of this study was to investigate if multimorbidity measures in geriatric rehabilitation inpatients differ in their association with mortality, dependent on a diagnosis of cancer.