batterydata/paper-abstracts huggingface dataset:
Mechanical properties of electrode materials have significant influence over electrochemical properties as well as mechanical integrity of lithium-ion battery cells. Here, anode and cathode in a commercially available 18650 NCA (Nickel Cobalt Aluminum Oxide)/graphite cell were comprehensively studied by tensile tests considering material anisotropy, SOC (state of charge), strain rate and electrolyte content. Results showed that the mechanical properties of both electrodes were highly dependent on strain rate and electrolyte content; however, anode was SOC dependent while cathode was not. Besides, coupled effects of strain rate and SOC of anodes were also discussed. SEM (scanning electron microscope) images of surfaces and cross-sections of electrodes showed the fracture morphology. In addition, mechanical behavior of Cu foil separated from anode with different SOC values were studied and compared. Finally, constitutive models of electrodes considering both strain rate and anisotropy effects were established. This study reveals the relationship between electrochemical dependent mechanical behavior of the electrodes. The established mechanical models of electrodes can be applied to the numerical computation of battery cells. Results are essential to predict the mechanical responses as well as the deformation of battery cell under various loading conditions, facilitating safer battery design and manufacturing.
Self-determination theory is a macrotheory of human motivation that describes fundamental matters such as personality development, goals and aspirations, and self-regulation. Basic psychological needs theory, a subtheory of self-determination theory, postulates that the needs for autonomy, competence, and relatedness are universal and the satisfaction thereof essential for human functioning. Despite the theory’s strong universality claim, almost no studies tested the assumption on the African continent. The present study addressed this by exploring the factorial validity of English, Afrikaans, and Setswana versions of the Basic Psychological Needs Scale (N = 1056). After incorporating a negative-worded method effect and removing several problematic items, the fit of the intended three-factor model was good for the Afrikaans version, marginal for the English version, and poor for the Setswana version. The resulting factors’ reliabilities were low. Configural, metric, and partial scalar invariance were established between the English and Afrikaans versions. Although these findings primarily highlighted problems with the particular scale, there is also the possibility that it could have implications for the validity of the universality assumption of basic psychological needs theory and/or assumptions about denotations or manifestations of the main constructs in various cultural contexts. The study indicated the conceptual and linguistic complexities involved in assessment across diverse and multicultural contexts.
This paper proposes state-of-charge (SOC) estimation algorithms that utilize a filtered battery terminal voltage without measuring the current. These methods extract an estimated open-circuit voltage (OCV) or current from the battery terminal voltage through equivalent circuit model-based filters, which streamlines the estimation process. In the methods, the OCV values derived from the corresponding SOCs are used to extract the filter coefficient for ease of implementation. The relationship between the model's accuracy and estimation performance is investigated, and the variation of the SOC estimation error due to the model parameter tolerance is also derived by the Monte Carlo simulation tool to confirm the practicality of the method. To validate the performance of the proposed approach, a parameter extraction profile and an actual mobile phone profile are applied to a 2.6 Ah prismatic Li-ion battery. The experimental results show the feasibility of the proposed SOC estimation algorithm to within a 5% SOC estimation error.
Li, Al co-doped LiMn2O4 (Li1+x Mn2−x−y Al y O4, 0 ≤ x ≤ 0.12, 0 ≤ y ≤ 0.1) cathode has been synthesized via a solid-state reaction designedly using industrial raw materials in bulk scale (>20 kg). The multicomponent substitution effects on the crystal structures are examined systematically by Rietveld refinement of X-ray diffraction, and the resultant electrochemical properties for Li-ion batteries are also evaluated by galvanostatic charge–discharge and electrochemical impedance spectroscopy measurements. As a result, Li, Al co-doping significantly changes the unit cell parameter and atomic arrangement. With the increasing of doping levels, a cell dimension contracts with concomitant changes in bond length, whereby the MO6 octahedron (M = Mn/Li/Al) shrinks to provide structural integrity and the LiO4 tetrahedron expands to facilitate a fast electrochemical process. The strong spinel-framework contributes to a better structure-stabilization, resulting in a superior capacity retention ratio of 90% after 200 cycles at 0.5 C at 55 °C for the optimized composition (Li1.06Mn1.86Al0.08O4), which possesses an initial value of 102 mAh g−1. Meanwhile, the expansion of LiO4 tetrahedron leads to better high-rate performance, bringing about a capacity of 88 mAh g−1 upon cycling at 10 C at 55 °C. Further, Li1.06Mn1.86Al0.08O4 displays lower impedance than that of the pristine LiMn2O4.
This paper reports an efficient fabrication of N-doped graphene quantum dots (GQDs) showing controllable chemical and fluorescence (FL) properties through infrared carbonization (IRC) of citric acid and urea. The GQDs prefer to form an equilibrium shapes of circle with an average particle size ranged from 5 to 10 nm. The N/C atomic ratio in GQDs can be precisely tailored in a range from 21.6 to 49.6 at.% by simply controlling the weight ratio of citric acid to urea. With increasing the urea content, the GQDs not only contain N-doped graphene but also incorporate with crystalline cyanuric acid, forming a binary crystallinity. The quantum yield of 22.2% is achieved by N-doped GQDs, prepared from the IRC synthesis of chemical precursor at the citric acid/urea at 3:1. Excessive N and cyanuric acid can lead to FL quenching, red shift and wide spectral distribution. The design of GQDs possesses a multiple chromophoric band-gap structure, originated from the presence of cyanuric acid, defect-related emissive traps, and functional group distributions. This work offers an effective and inspiring approach to engineering both chemical compositions and unique crystalline structures of GQDs, and will therefore facilitate their fundamental research and applications to optical, sensing, energy and biological fields.
Catalysts of Co(OH)2 supported on polypyrrole-modified Super P carbon and on polypyrrole-modified BP 2000 carbon are prepared by a chemical method. The structure and morphology of the catalysts are characterized by X-ray diffraction, X-ray photoemission spectroscopy and transmission electron microscopy. BP 2000 carbon demonstrates larger specific surface area, lower crystallization degree and lower electrochemical resistance than Super P carbon. The surface characteristics of the carbon support have notable influences on the morphology and electrocatalytic activity of Co(OH)2. Co(OH)2 distributes much homogeneously on the polypyrrole-modified BP 2000 with more polypyrrole content, and exhibits higher electrocatalytic activity compared with that on polypyrrole-modified Super P carbon. The DBFC using Co(OH)2 supported on polypyrrole-modified BP 2000 as the catalysts demonstrates fairly good performance (160mWcm−2) under ambient conditions.
The graphene/cubic cobaltite oxide nanosheets (rGO/Co3O4) with a face centered cubic crystalline structure are synthesized and are exploited as effective cathode catalysts in high performance Lithium-air batteries. The morphological images enunciate that 220 nm average diameter of Co3O4 nanosheets are effectively anchored over the graphene sheets and the diameter of individual nanoparticles that construct the cubic nanosheets is 5 nm. The growth and composite formation mechanisms of prepared nanostructures are identified from Raman and FT-IR spectroscopic techniques. rGO/Co3O4 composite exhibits a lower voltage, high discharge capacity of 4150 mAh g−1 and displays superior cyclability without any capacity losses, signifying the excellent rechargeability of the fabricated electrodes. The post mortem analysis of electrodes specify the existence of lithium peroxide (Li2O2), lithium oxide (Li2O) and lithium carbonate (Li2CO3) discharge products, revealing the involved electrochemical reaction of Lithium-air batteries. The excellent electrochemical properties of rGO/Co3O4 composite is due to the combination of rapid electrokinetics of electron transport and high electrocatalytic activity toward oxygen reduction reaction given via the synergetic effects of rGO and cubic Co3O4 nanosheets. These findings provide fundamental knowledge on understanding the influence of morphological and structural properties of graphene based nanostructures toward Lithium-air battery performances.
Microarray expression profiling on the model plant Arabidopsis thaliana has contributed to the elucidation of plant defence responses and resistance against disease. An Arabidopsis mutant, cir1 (constitutively induced resistance 1), previously showed enhanced resistance to the pathogenic biotrophic bacterium Pseudomonas syringae pv tomato (Pst) DC3000. It was hypothesised that induced or repressed genes in cir1 may play a role in conferring resistance against this pathogen. We investigated differential gene expression in wild type and cir1 plants without pathogen challenge using a custom 500-probe microarray, biased towards defence-response and signalling genes, to identify transcripts, which may be required for resistance in cir1. Several genes were found to be induced in cir1 at a significance threshold of −log10(p) equal to 3 (p <0.001) using a mixed model ANOVA approach. The induction of the genes encoding AtACP1 (sodium inducible calcium binding protein), AtP2C-HA (protein phosphatase 2C), AtGSTF7 (glutathione-S-transferase), tryptophan synthase beta-like and AtPAL1 (phenylalanine ammonia lyase 1) and the repression of AtEREBP-4 (ethylene response element binding protein 4) and HFR1 (long hypocotyl in far-red 1) in cir1 correlates with publicly available microarray data which shows the same genes differentially expressed in a similar manner in Arabidopsis plants infected with Pst. This observation supports our hypothesis that these genes contribute to disease resistance in cir1.
Macroporous material of Sn–Cu alloy of different pore sizes designated as anode in lithium-ion batteries were fabricated through colloidal crystal template method. The structure and electrochemical properties of the macroporous Sn–Cu alloy electrodes were examined by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and galvanostatic cycling. The results demonstrated that the electrodes of macroporous Sn–Cu alloy with pore size respectively of 180 and 500nm can deliver reversible capacity of 350 and 270mAhg−1 up to 70th cycles of charge/discharge. The cycle performance of the macroporous Sn–Cu alloy of 180nm in pore size is better than that of the macroporous Sn–Cu alloy with 500-nm-diameter pores. It has revealed that the porous structure of the macroporous Sn–Cu alloy material is of importance to strengthen mechanically the electrode and to reduce significantly the effect of volume expansion during cycling.
A series of acetonitrile solutions of the N(SO2CF3)2 − salts of Li, Na, K, Cs, Mg and Ca are examined in a systematic study of electrolytes based on the alkali and alkaline earth series of metal cations. Reference-electrode experiments show that the relatively large and polarisable cesium ion results in the highest capacitance at the negative electrode. We also report current collector corrosion behavior which is anomalously severe for the Mg based electrolyte. Charge-discharge kinetics are investigated using impedance spectroscopy, and it is shown that the new electrolytes have no power advantage over an organic cation based electrolyte at 0.5M concentration. Constant voltage device testing at 2.7V and 65°C reveals a very large electrochemical stability advantage for the K and Cs based devices over the hitherto more commonly studied Li systems.
Metal-metal oxide composite materials have been garnering wide attention due to their extraordinary properties and applications in several areas. Ni-NiO is an important composite; its synthesis and properties have been of increased interest with regards to prominent applications in many fields. This article provides for the first time a comprehensive review of the cutting-edge research activities that focus on rational synthesis, characterization techniques, novel properties and applications of the Ni-NiO composite. While the formation mechanism of this composite is still vague, much attention has been given to the reported formation mechanisms using different precursors in one-pot synthesis, and thus, a formation mechanism and green synthesis route have been proposed. All the applications of the Ni-NiO composite in different fields including magnetic materials, ion-lithium battery, supercapacitors and catalytic activities are also emphasized. It was proved from the available literature that metallic Ni was obtained into the skelton of NiO by the reduction process during the calcination through the production of adventitious H2 via the gasification-like process.
Herein we report on an in-situ electroanalytical technique to investigate electrode-electrolyte behaviour during cycling in a conventional symmetrical electrochemical capacitor system based on an activated carbon (AC) electrodes with 1 M tetraethylammonium tetrafluoroborate (TEABF4) in acetonitrile (ACN) as the electrolyte. The electrochemical cell is based on a Swagelok T-junction, with the perpendicular port being used for a Ag/Ag+ (0.01 M AgNO3 in ACN) reference electrode. Situated between the opposing AC electrodes, between two separators, is a Pt sensing electrode, the potential of which is either monitored or controlled to explore either electrolyte fluxes during cycling, or the formation of soluble species in the electrolyte, respectively. It was deduced that electrolyte ions are strongly associated with the AC electrodes rather than between the electrodes even without an applied potential. Furthermore, aging of the electrochemical system with cycling (cyclic voltammetry) is also explored. Even with identical electrodes it is noted that the individual electrodes behaved differently as a result of anion versus cation association. Finally, at cell voltages approaching 2 V, oxidation of the positive electrode is observed, liberating species into the electrolyte. The implications of these observations have been discussed.
Calcium ferrite (CaFe2O4)-type LixMn2O4 was prepared via high-pressure and soft chemical synthesis method. The framework structure of CaFe2O4-type NaMn2O4 was synthesized from the stoichiometric mixture of Na2CO3 and MnO2 annealed by 1273 K for 1 h under 4.5 GPa. Na/Li ion-exchange of the CaFe2O4-type NaMn2O4 was carried out by soaking molten LiNO3 at 633 K for 12 h. The electrochemical properties of the ion-exchanged CaFe2O4-type LixMn2O4 were measured. The initial discharge profile in the voltage range from 4.0 to 1.0 V showed 458 mAh g−1 of the discharge capacity with two plateaus near 3.7 V and 2.7 V (vs. Li/Li+). The discharge capacity was decreased with increasing the cycle number. After 30 cycles, the capacity was decreased to 375 mAh g−1. When the range was set between 4.8 and 3.0 V, the discharge capacity was 113 mAh g−1 in initial, and 111 mAh g−1 after 50th cycle. The reference CaFe2O4-type LiMn2O4 was prepared via one-step high-pressure synthesis and compared the electrochemical properties with the ion-exchanged sample. The initial discharge capacity of the one-step synthesized one was 108 mAh g−1 at 1.0 V (vs. Li/Li+), which was 73% lower than the value of the ion-exchanged one.
The effects of single, binary and ternary contaminant mixtures containing propene (C3H6), acetonitrile (CH3CN), and bromomethane (CH3Br) on proton exchange membrane fuel cells have been studied. Changes in polarization curves, electrochemical impedance spectroscopy spectra, electrochemical catalyst surface areas by cyclic voltammetry, and hydrogen crossover through the membrane by chronoamperometry are used to define the extent of recovery and irrecoverable losses after the contamination period and to understand the contaminant interactions. CH3CN in the contaminant mixture mitigates the decrease in oxygen reduction reaction kinetics and the increase in oxygen and water mass transport resistance, while C3H6 speeds up the above situations. The hydrolysis of CH3CN results in the formation of ammonium ions, which exchange with membrane protons, leading to an increase in the membrane resistance. CH3Br increases the decomposition of the Nafion® ionomer. Bromide accumulation on the catalyst surface leads to large catalyst area losses for the mixtures containing CH3Br. Competitive adsorption on Pt active sites exists between CH3CN and CH3Br. However, there is noncompetitive adsorption between C3H6 and CH3Br or CH3CN.
Polyaniline (PANI) is well-known for its remarkable electrical and optical properties which find immense applications in polymer optoelectronics. Though extensive work has been reported in polyaniline samples both in bulk and thin film forms, much attention has not been paid to investigate the quantum confinement effects in ultrathin polyaniline films. The present work is devoted to the search for quantum confinement effects in ultrathin polyaniline films having nanometer thickness, prepared from m-cresol, through conventional and less sophisticated spectroscopic techniques. Remarkable blue-shift has been observed in the absorption spectrum of these samples. Much intense photo-luminescent emission with considerable blue-shift observed in these ultrathin films is cited as the clear evidence for confinement effects.
As Thai people living with HIV/AIDS gain increasing access to antiretroviral (ARV) therapy, it is important to evaluate the impact this has not only on clinical outcomes, but also on patients' functional status and well-being. In this study, we translated, culturally adapted and tested the reliability and validity of two widely-used health-related quality of life questionnaires - the MOS-HIV Health Survey and the SF-12 - in people living with HIV/AIDS in Northern Thailand. Methods: Questionnaires were administered to 100 patients at community hospital outpatient ARV clinics in northern Thailand. Reliability was estimated using Cronbach's alpha, while evidence for validity was tested using known-groups comparison based on CD4 group, symptom distress score, bed days and days of reduced activity in the past three months.
Battery separators are characterized largely by their material and by their shape. In this paper options to achieve optimization of polyethylene separator properties are discussed, based on reasonable variations in material and shape, in particular with respect to electrical resistance and chemical stability. The raw materials of polyethylene separators, i.e. silica, ultrahigh-molecular weight polyethylene, mineral oil and some additives are presented, their relative amounts are varied, and the resulting properties are evaluated with regard to oxidation stability, deposits generated, puncture strength, and electrical resistance. Distinct consideration must be given to the dimensional parameters of both the separator sheet and the distance-setting ribs. Various proposals, in particular for the latter, are referred to in the literature without critical evaluation of their effect on battery performance. Some considerations for optimized profile design and initial battery results are reported.
The effect of sodium on the electrochemical behavior of lithium in alkaline electrolyte with additives was investigated via hydrogen evolution rate, discharge current density, anodic potential, XRD (X-ray diffraction) and SEM (scanning electron microscope) in this paper. The results show that minor addition of sodium to lithium slightly decreases the hydrogen evolution at the electrode. Addition of 0.057wt.% Na to lithium has a minor effect on discharge current and anodic potential of lithium anode. The scanning electron microscopy (SEM) result shows that the lithium–sodium alloy surface is less porous than the lithium surface. Theoretical analysis indicates that the water activity at the Li–Na anode/electrolyte interface is reduced by LiOH+NaOH solution formation. Hydrogen evolution decrease, prompted by the addition of sodium to lithium, is related to the water activity reduction at the metal/electrolyte interface and reduced porosity of the film.
Urchin-like Ni(OH)2–Co(OH)2 hollow microspheres were successfully synthesized by a microwave-incorporated hydrothermal method. The Ni(OH)2–Co(OH)2 hollow microspheres achieved a high specific capacitance of 2164Fg−1 at 1Ag−1 and long-term cycle life. Electrochemical data reveal that the Ni(OH)2–Co(OH)2 hollow microspheres exhibits much better electrochemical reversibility and specific capacitance retention than that of the single Ni(OH)2 or Co(OH)2 based on peak potential difference, symmetry of charge–discharge curves, and specific capacitances at high charge–discharge rates. Furthermore, the designed Ni(OH)2–Co(OH)2/graphene asymmetric supercapacitor displays good reversibility and a high specific capacitance of 169Fg−1 at 1Ag−1, 145Fg−1 at 3Ag−1, and 116Fg−1 at 5Ag−1, indicating a good ability to deliver a high energy density at a high power density. These results proved that the Ni(OH)2–Co(OH)2 hollow microspheres can be promising electroactive materials for supercapacitor and the microwave-incorporated hydrothermal method provided a one-step, template-free, and cost-effective route for fabricating pseudocapacitive materials in 3-D form.
Despite the considerable success of comprehensive tobacco control efforts, tobacco use remains one of the greatest preventable causes of death and disease today. Over half of all smokers in the US make quit attempts every year, but over 90% relapse within 12 months, choosing the immediate reinforcement of smoking over the long-term benefits of quitting. Conceptual and empirical evidence supports continued investigation of high frequency repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex in reducing relapse and decreasing cigarette consumption. While this evidence is compelling, an optimal dosing strategy must be determined before a long-term efficacy trial can be conducted. The goal of this study is to determine a dosing strategy for 20 Hz rTMS that will produce the best long-term abstinence outcomes with the fewest undesirable effects.