batterydata/paper-abstracts huggingface dataset:
The nanometer MnO2 has outstanding electrochemical performance theoretically, but it is not suitable for actual utilization, which may result in capacity decrease and resource waste. In this study we have utilized the characterizations of the nanometer material, synthesized a type of nanometer α-MnO2 through KMnO4 and KNO3 with hydrothermal method, and mixed the products into micron electrolytic manganese dioxide (EMD) to enhance the electrochemical performance of the electrode. The cyclic voltammogram and galvanostatical discharge measurements of the samples were investigated. It is found that the 50% nanometer MnO2 mixed electrode has the best electrochemical performance. The electrochemical performance improvement mechanism of the sample nanometer MnO2 mixed into micron EMD was discussed. With the existence of electrolyte, the nanometer MnO2 particles filled into the interspaces of the micron EMD particles, the mass and charge transfer conditions of the electrode reaction were improved, and the electrode polarization was diminished.
Ni3S2 with different morphologies (nanoflakes, nanosheets, nanoparticles) have been synthesized by simply altering the sulphur sources (thioacetamide, thiourea and sodium thiosulfate) of a hydrothermal process. The obtained three carbon-free nanostructures are evaluated as negative electrode materials for lithium ion batteries. Ni3S2 nanoflakes exhibit the best cycle and rate performance among the samples prepared, which is benefited from their small particle size and porous structure. It maintains a reversible capacity of 861 mA h g−1 after 70 cycles at a current density of 0.4 A g−1, and a reversible capacity of 514 mA h g−1 even at a current density as high as 4.0 A g−1. These features make Ni3S2 nanoflakes a promising candidate as high performance negative electrode material for lithium ion batteries.
Executive function (EF) is the set of neuro-cognitive processes associated with self-regulation, decision-making, and goal-directed behavior. The goal of this study is to examine cross-sectional relationships between EF and latent classes of youth characterized by patterns of obesity-related health behaviors (i.e., high fat/high sugar intake, fruit and vegetable intake, physical activity, sedentary behavior, and dieting). Participants were 997 4th grade youth in a school-based obesity prevention program. Cross-sectional relationships at study baseline between established latent classes of obesity risk and EF problems were assessed. General linear models demonstrated that EF problems were associated with classification into two unhealthy latent obesity risk classes. One potential implication of study findings is that obesity intervention efforts include EF promotion content tailored for latent classes of youth at different levels of obesity risk.
The market for valve-regulated lead−acid (VRLA) batteries is growing steadily and will be given a further boost as the market for 36-V batteries for the 42-V PowerNet develops over the next few years. The manufacture of VRLA batteries poses, however, a number of complex technical problems that are not experienced in the manufacture of conventional flooded batteries. For the large-scale manufacture of automotive batteries or other small VRLA batteries of 100Ah or less, jar formation rather than plate formation and dry charge would seem to be a logical and economically sound decision. For this to be successful, however, a number of key issues need to be reviewed, starting with a detailed consideration of battery design. This paper reviews issues associated with the jar formation of VRLA batteries. Guidance is given concerning filling techniques (gravity or vacuum fill), the formation process, charging techniques, and formation algorithms. Battery design and separator optimisation is discussed. The properties of the separator, e.g. wicking rate, fibre composition, surface area and compression, may have a critical impact on acid filling and jar formation, and may partially determine the filling and formation conditions to be used. The control of temperature during formation is particularly important. Formation algorithms and temperature data are presented. Attention is drawn to the possible loss of plate-group compression during the formation process, and how this may be avoided.
In this paper we introduce a Simplified Single Particle Model (SSPM), which is obtained from the general mathematical formulation of Li-ion batteries. The model is validated by using different commercial graphite/LiFePO4 cells, and results show agreement with more complicated models and experimental data for low operating currents of less than 1C. A maximum relative error of less than 2% can be observed to estimate cell voltage in the plateau region of the charge/discharge curves. Therefore, the proposed model is suitable in the case of stand-alone renewable energy systems, where battery current is typically lower than C/10. By increasing the current, the SSPM deviates from more accurate models and experimental data. However, it is sufficiently precise and computationally efficient to be used in the simulation and optimization framework of off-grid renewable energy systems. Finally, the proposed model will be applied to two different case studies; one for an installed PV-battery and the other for a Wind-battery system which are located near Zaragoza, Spain, in order to predict battery state over time.
It is desirable that a thin film lithium–electrolyte interface is flexible and self-healing to accommodate the large volume expansion during lithium deposition without rupturing and impede electrolyte decomposition. The most influential area of polymer thin films is the alternating adsorption of oppositely charged polyelectrolytes popularized by the introduction of the layer-by-layer (LBL) self-assembly technique. We demonstrate that the introduction of a pH sensitive component into a nanomembrane assembled by the LBL method can have a dramatic effect on the interface governing the coulombic efficiency and morphology of lithium depositing.
Equal amounts of Fe- and Ni-substituted Li2MnO3 (chemical formula: Li1+x [(Fe1/2Ni1/2) y Mn1−y ]1−x O2, 0< x <1/3, 0.2≤ y ≤0.8) were synthesized using coprecipitation–hydrothermal–calcination. Although the samples with y less than 0.5 are only monoclinic Li2MnO3-type structure (C2/m), samples with y larger than 0.6 show a two-phase nature consisting of the monoclinic phase and cubic LiFeO2 phase ( F m 3 ¯ m ). Electrochemical characterization as a positive electrode shows that the Li2O extraction region disappears above y =0.6 on initial charging and that the energy density is decreased drastically above the composition on initial discharging. The optimized transition metal ratios are y =0.4 and 0.5 because the initial average discharge voltage increases with y and the maximum initial cycle efficiency is attained. In the optimized composition, the Fe- and Ni-substituted Li2MnO3 is a 3.5V class positive electrode, with similar charge and discharge profiles to those of the most attractive active material, NMC positive electrode (chemical formula: Li1+x [(Co1/2Ni1/2) y Mn1−y ]1−x O2, 0< x <1/3, 0.2≤ y ≤0.8). Consequently, Fe can be used as an activator in combination with Ni for constructing “Co-free” Li2MnO3-based positive electrodes. The calcination-condition-dependence of electrochemical properties at the optimized composition is also examined. The effects of the Fe valence state on initial charge–discharge curves are discussed.
Lithium sulfur cells were prepared by composing with sulfur cathode (PEO)6LiBF4 polymer electrolyte and lithium anode. (PEO)6LiBF4 polymer electrolyte was prepared under three different mixing conditions: stirred polymer electrolyte (SPE), ball-milled polymer electrolyte (BPE) and ball-milled polymer electrolyte with 10wt%Al2O3 (BCPE). The effects of ball milling and additive were investigated by discharge test according to depth of discharge. The initial discharge capacity of lithium sulfur cell using BCPE was 1670mAhg−1-sulfur, which was better than those of SPE and BPE, and approximately equal to the theoretical capacity. The cycle performance of Li/(PEO)6LiBF4/S cell was remarkably improved by the addition of Al2O3.
An electrochemical characterization of a silver molybdenum oxyfluoride perovskite positive electrode for Li batteries was investigated as a function of synthesis condition, stoichiometry and effect of Mo and Ag derived second phases. A detailed in situ electrochemical study by XAS, Raman, and XRD was performed, revealing a 3 electron silver displacement or conversion reaction at >3V and a 2 electron reduction of Mo6+ to Mo4+ in the region <3V.
The exploration of next-generation sodium-ion batteries (SIBs) is a worldwide concern to replace the current commercial lithium-ion batteries, mitigating the increasing exhaustion of Li resources. Sodium transition metal oxides are considered to be one of the most promising cathode materials for SIBs. The anionic redox reaction in Li-rich transition metal oxides is capable of providing extra capacity in addition to the cationic redox activities in lithium-ion batteries. A similar phenomenon exists in SIBs, which even applies to Na-deficient transition metal oxides. Moreover, transition metal oxides with mixed phase also demonstrate great potential. In this review, studies on anionic redox are first systematically introduced. The up-to-date advances on high-capacity transition metal oxide cathode materials for SIBs are then classified and summarized in different groups associated with or without anionic redox. The existing challenges as well as available solutions and strategies are discussed, and proposals with new insights are made at the end. It is expected that this work can provide new perspectives on controlling the anionic redox activity and finding novel high-capacity oxide cathode materials for SIBs.
Reliable cognitive assessment for non-western cultures is difficult given that mainstream tests typically rely on western concepts, content and values. Despite recognition of the scarcity of appropriate tests for Aboriginal people over many years, limited practical development has occurred. This study aimed to identify barriers to assessment for clinicians working with Aboriginal people in a remote context, and evaluate characteristics of assessments that clinicians considered to be more or less appropriate and thereby identify potential ways forward.
Polymer-clay nanocomposite (PCN) materials were prepared by intercalation of an alkyl-ammonium ion spacing/coupling agent and a polymer between the planar layers of a swellable-layered material, such as montmorillonite (MMT). The nanocomposite lithium polymer electrolytes comprising such PCN materials and/or a dielectric solution (propylene carbonate) were prepared and discussed. The chemical composition of the nanocomposite materials was determined with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, which revealed that the alkyl-ammonium ion successfully intercalated the layer of MMT clay, and thus copolymer poly(vinylidene fluoride-hexafluoropropylene) entered the galleries of montmorillonite clay. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of the lithium polymer electrolyte. Equivalent circuits were proposed to fit the EIS data successfully, and the significant contribution from MMT was thus identified. The resulting polymer electrolytes show high ionic conductivity up to 10−3 Scm−1 after gelling with propylene carbonate. The PCN materials exhibit good electrochemical stability and could be potentially used in lithium secondary battery.
For the vehicular operation, due to the voltage and power/energy requirements, the battery systems are usually composed of up to hundreds of cells connected in series or parallel. To accommodate the operation conditions, the battery management system (BMS) should estimate State of Charge (SOC) to facilitate safe and efficient utilization of the battery. The performance difference among the cells makes a pure pack SOC estimation hardly provide sufficient information, which at last affects the computation of available energy and power and the safety of the battery system. So for a reliable and accurate management, the BMS should “know” the SOC of each individual cell. Several possible solutions on this issue have been reported in the recent years. This paper studies a method to determine online all individual cell SOCs of a series-connected battery pack. This method, with an equivalent circuit based “averaged cell” model, estimates the battery pack’s average SOC first, and then incorporates the performance divergences between the “averaged cell” and each individual cell to generate the SOC estimations for all cells. This method is developed based on extended Kalman filter (EKF), and to reduce the computation cost, a dual time-scale implementation is designed. The method is validated using results obtained from the measurements of a Li-ion battery pack under three different tests, and analysis indicates the good performance of the algorithm.
Sulfonated poly(tetramethydiphenyl ether ether ketone) (SPEEK) with various degree of sulfonation is prepared and first used as ion exchange membrane for vanadium redox flow battery (VRB) application. The vanadium ion permeability of SPEEK40 membrane is one order of magnitude lower than that of Nafion 115 membrane. The low cost SPEEK membranes exhibit a better performance than Nafion at the same operating condition. VRB single cells with SPEEK membranes show very high energy efficiency (>84%), comparable to that of the Nafion, but at much higher columbic efficiency (>97%). In the self-discharge test, the duration of the cell with the SPEEK membrane is two times longer than that with Nafion 115. The membrane keeps a stable performance after 80-cycles charge–discharge test.
Cyclic voltammogram (CV) and differential voltage analysis (DVA) are two effective techniques to analyze the aging mechanism and estimate the aging state of a battery. However, the effectiveness of the two methods reported previously is based on single battery cells. In this paper, a comparison of the two methods is stated, and the equivalent relation is further derived. Besides, a local data symmetry method is introduced to calculate the differential voltage (DV) curve. The DV curves calculated by the proposed method are much smoother than that by the numerical-derivative method. Based on the location interval of two inflection points in the DV curve, a new method is inferred for lithium iron phosphate (LiFePO4) battery cells, and is applied to estimate the state of health (SOH) of battery modules. The applicability of the method is further verified via battery module simulation and experimental data. The results show that the DV curves fluctuate and do not overlap in the voltage plateau region due to the uneven currents flowing through each in-parallel battery cells. There is also a good linear regression of the two inflection point location interval versus battery module capacity within 2% error bounds, suggesting that the DVA method inferred from battery cells can be directly applied to battery modules.
The exfoliation/dispersion of two-dimensional (2D) materials is of great importance due to their unique properties and applications in electronics as well as energy storage devices. In this paper, we address the challenge of dispersing 2D materials in a scalable and environmentally friendly way. A methodology to efficiently disperse 2D materials [boron nitride (BN) and molybdenum disulfide (MoS2)] in an aqueous solution using a green dispersant, nanofibrillated cellulose (NFC), was introduced. The stable high concentration BN/MoS2 aqueous solutions allow the formation of multifunctional composites and may facilitate roll-to-roll manufacturing. Films and fibers with excellent mechanical strength were fabricated with the BN solution. Additionally, strong and flexible MoS2 films were prepared and used as anodes for sodium ion batteries, indicating flexible battery applications.
Although deterioration of higher-order visual information processing abilities occurs in Alzheimer's disease (AD), few cross-sectional or longitudinal studies have systematically examined this deficit. The performance of 135 patients with probable AD and 97 matched normal control (NC) participants were compared on a structured test of perceptual organization ability, the Hooper Visual Organization Test (VOT). Both the standard VOT score and a derived score that corrected for anomia were significantly lower for AD patients than for NC participants, but neither score was particularly effective at distinguishing between the groups. The derived VOT score proved to be a more effective measure of visuospatial functioning than the standard VOT score as it loaded with other visuospatial tests in a principal components analysis while the standard score loaded with language tests. The VOT was sensitive to severity of dementia in the AD patients. Longitudinal assessment of 37 of the AD patients and 46 NC participants revealed significant decline over one year in the VOT scores of AD patients, but not in those of NC participants. These results indicate that higher-order visual information processing is impaired in patients with AD and gradually deteriorates with disease progression. This deficit may not be a particularly salient early marker of the disease, but it may be useful in tracking disease course.
Prism ZnO nanomaterials coated with Ca(OH)2 were prepared by direct precipitation. TEM micrographs showed that dendritic Ca(OH)2 seemed to attach on the surface of nanosized ZnO. The XRD patterns indicated that the coating was Ca(OH)2·2Zn(OH)2·2H2O. The nanosized ZnO coated with Ca(OH)2 as the anode materials were investigated by the charge–discharge cycle measurement and EIS. The combination of ZnO nanomaterials and Ca(OH)2 prevented the discharge product ZnO from dissolving in the electrolyte. Therefore, the Ca(OH)2-coated ZnO nanomaterials exhibited higher electrochemical activity than the pure nanosized ZnO, including high the discharge capacity and discharge middle voltage, low the charge middle charge voltage. Although Ca(OH)2 resulted in more difficult activation, EIS showed that the charge-transfer resistance was lower than that of the pure ZnO nanomaterials.
The sol-gel method is applied to prepare nano-sized LMNCO lithium-rich layered oxides by adding of composite organic acid (citric acid & tartaric acid). The effect of composite organic acid on the microstructure of Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) Li-rich cathode material is explored in this work. The results confirm the existence of interactions between the composite organic acid molecules and the precursors, and formation of stronger space steric effect. The stronger space steric effect can effectively prevent the growth of precursor particles in the presintering process at 550 °C for 5 h, which eventually contributed to the fabrication of nano-sized LMNCO. According to EIS analysis, the synthesized LMNCO has low charge transfer resistance of 135.4 Ω. Furthermore, it shows excellent electrochemical performance with a discharge capacity of 263.1 mAh g−1 at 0.1 C and 187.9 mAh g−1 at 5 C.
The cubic Ca/Ta-substituted Li6.55(La2.95Ca0.05)(Zr1.5Ta0.5)O12 (LLCZTO) electrolytes were synthesized at 800 °C with Li3BO3 as additives. The optimal amount of Li3BO3 and its influences on the microstructure, crystal structures, Li+ conductivity and the stability of the Li6.55(La2.95Ca0.05)(Zr1.5Ta0.5)O12 were studied by SEM, XRD and EIS. Among all the samples, when the molar ratio of Li3BO3 to the Li6.55(La2.95Ca0.05)(Zr1.5Ta0.5)O12 is 4:5, the highest Li+ conductivity of 1.33 × 10−4 S cm−1 at 30 °C is obtained. When the LLCZTO samples are exposed in air, the Li+ conductivity is deteriorated possibly owing to the side reactions between the LLCZTO and the H2O or CO2 in the air. The Li3BO3 addition can alleviate such deterioration of the Li+ conductivity.
Nanocomposite polymer electrolytes based on high-molecular weight poly(oxyethylene) (POE) were prepared from high aspect ratio cellulosic whiskers and lithium trifluoromethyl sulfonyl imide (LiTFSI). Prior to the polymer electrolyte characterization, the polymer/whiskers nanocomposites were characterized using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Interactions between cellulose and POE were evidenced. The main effect of the filler was a thermal stabilization of the storage modulus for the composites above the melting point of the complexes POE/LiTFSI. The ionic conductivity was quite consistent with the specifications of lithium batteries.
LiFePO4/C materials are synthesized via in-situ coating of LiFePO4 by using 1-butyl-3-methylimidazolium dicyanamide ([BMIm][N(CN)2]) and glucose as carbon sources, respectively. The structure characterization results indicate that the carbon sources have no effect on the LiFePO4 particles, but have remarkable influence on the coated carbon films. It is found that the [BMIm][N(CN)2] carbon source leads to ultrathin (1–2 nm), uniform and highly graphitized carbon films. Due to this unique structure, the electrode materials fabricated by using [BMIm][N(CN)2] exhibit a superior electrode reaction reversibility, a capacity retention of 160.6 mAhg−1 (1.47% decay rate) after 50 cycles and a specific discharge capacity of 143.6 mAhg−1 at 1C, which is much better than the performance of the electrode materials synthesized with glucose.
Li–O2 cell is considered as an ideal choice for the electric vehicles due to its high energy density, but is now suffering from the large charge polarization and low practical capacity. In this context, three-dimensional network macro-porous CoO synthesized via a sol–gel method is applied as an efficient catalyst in Li–O2 cells to alleviate this situation. Compared to KB (Ketjen black EC600JD) based cells, the CoO/KB based cell exhibits much improved electrochemical performance at various current densities, including flatter discharge/charge plateau, lower polarization and higher specific capacity. In addition, the CoO/KB based cell maintains the discharge capacity up to 4500 mAh g−1 CoO/KB after being cycled at 0.1 mA cm−2 for 16 days under O2 atmosphere. This excellent electrochemical performance is attributed to the high catalytic activity and abundant macro-pores of our home-made CoO. This strategy of designing CoO might be a feasible way to obtain the Li–O2 cell with low polarization and high capacity.
Studies in small cells of vanadium redox flow battery have shown electrode compression to have significant effect on the cell performance. However, the results are conflicting and the data have been obtained for very high electrolyte circulation rates. In the present study, experimental investigations have been conducted in vanadium redox flow battery cells of active area of 426 cm2 and 936 cm2 over a wide range of operating conditions typical of large cells and for electrode compressions of 20, 35, 50 and 70%. The influence of operating current density, electrolyte circulation rate and state of charge has been specifically studied for both cell sizes. Cell pressure drop studies have also been conducted. Results show that the beneficial effects of electrode compression are mostly nullified by the loss of permeability at current densities in the range of 30–60 mA cm−2. At higher current densities, intermediate compressions of 35 and 50% are found to be the most optimal. Low state of charge tolerance is found to be better for the larger cell than the smaller cell, presumably due to better convective transport of electrolyte through the electrode arising from higher pressure drop.