batterydata/paper-abstracts huggingface dataset:
In this work, SnO2 quantum dots and graphene (G) nanocomposites (SnO2/G) were synthesized via a facile one-step hydrothermal method for the application of anode material in lithium ion batteries (LIBs). SnO2 quantum dots with a diameter ranging from 5 to 10nm were uniformly anchored on graphene nanosheets. SnO2/G nanocomposites can deliver high specific capacities of 860mAhg−1 after 50 cycles at a current density of 200mAg−1, and 683mAhg−1 at a current density of 1600mAg−1. Compared to the pure SnO2, the excellent improved electrochemical performance of SnO2/G nanocomposites for lithium ion storage can be attributed to the stable structure and the improved electron conduction channel provided by graphene with functional groups (FGs), such as C-OH, C=O and C-OOH. In order to further improve the SnO2/G nancomposites electrochemical performance, carbon thin layers were coated by the reduction of C2H2 gas via CVD technology (SnO2/G-C). However, SnO2/G-C showed an inferior performance compared to that of the SnO2/G without carbon coating. Through X-ray photoelectron spectroscopy (XPS) analysis, it was found that function groups play a critical role on the stability of SnO2/G nanocomposites. Such observation may thus instruct the design and implementation of graphene/metal oxides nanocomposites for high-performance LIBs anode materials.
The research recently carried out in our laboratories is summarized and discussed in the literature context towards green chemistry (dendritic catalysts) and nanotechnology: (i) construction of giant dendrimers far beyond the De Gennes dense-packing limit using building blocks efficiently synthesized by organo-iron activation of simple arene; (ii) use of water-soluble star-shaped organo-iron redox catalysts for nitrate and nitrite cathodic reduction in water; (iii) synthesis of giant dendritic stars from three generations of ruthenium-carbene dendrimers using ROMP and remarkable dendritic effects; (iv) assembly of dendronized gold nanoparticles that selectively recognized H2PO4 – and ATP2–; (v) electron-reservoir metallodendrimers serving as molecular batteries and the example of C60. To cite this article: D. Astruc et al., C. R. Chimie 6 (2003).
The capacity fade of Sony 18650 Li-ion cells increases with increase in temperature. After 800cycles, the cells cycled at RT and 45°C showed a capacity fade of 30 and 36%, respectively. The cell cycled at 55°C showed a capacity loss of about 70% after 490cycles. The rate capability of the cells continues to decrease with cycling. Impedance measurements showed an overall increase in the cell resistance with cycling and temperature. Impedance studies of the electrode materials showed an increased positive electrode resistance when compared to that of the negative electrode for cells cycled at RT and 45°C. However, cells cycled at 50 and 55°C exhibit higher negative electrode resistance. The increased capacity fade for the cells cycled at high temperatures can be explained by taking into account the repeated film formation over the surface of anode, which results in increased rate of lithium loss and also in a drastic increase in the negative electrode resistance with cycling.
LiCoO2 and LiMn2O4 cathodes were studied by X-ray diffractometry (XRD) and electron diffraction after ageing in the charged state at elevated temperature. Some cathodes were stopped at different times during ageing and XRD measurements were taken to monitor changes in the crystal structure over ageing time. The results indicate that Li-ions intercalate into the cathodes lattice during ageing thus decreasing the available discharge capacity. Analysis of electron diffraction patterns of LiCoO2 and LiMn2O4 retrieved from the cathodes after ageing shows that irreversible crystallographic transformations have taken place in both electrodes. Dark field imaging illustrates that LiCoO2 forms a layer of spinel phase on its surface. In LiMn2O4 a tetragonal distorted spinel is observed when the cathode has been in the 3V regime for considerable length of time.
Animal models of Alzheimer’s disease have suggested that tau pathology propagation, facilitated by amyloid pathology, may occur along connected pathways. To investigate these ideas in humans, we combined amyloid scans with longitudinal data on white matter connectivity, hippocampal volume, tau positron emission tomography and memory performance in 256 cognitively healthy older individuals. Lower baseline hippocampal volume was associated with increased mean diffusivity of the connecting hippocampal cingulum bundle (HCB). HCB diffusivity predicted tau accumulation in the downstream-connected posterior cingulate cortex in amyloid-positive but not in amyloid-negative individuals. Furthermore, HCB diffusivity predicted memory decline in amyloid-positive individuals with high posterior cingulate cortex tau binding. Our results provide in vivo evidence that higher amyloid pathology strengthens the association between HCB diffusivity and tau accumulation in the downstream posterior cingulate cortex and facilitates memory decline. This confirms amyloid’s crucial role in potentiating neural vulnerability and memory decline marking the onset of preclinical Alzheimer’s disease.
The formation of the solid electrolyte interface (SEI) layer on the surface of the anode electrode of a lithium ion battery prevents further electrolyte decomposition reaction. However, at certain battery operating conditions, the SEI breakdown leading to more electrolyte decomposition reactions that form several species on the anode electrode surface. This paper focuses on the effect of battery potential and charge rate on the decomposition side reaction on the anode electrode of a lithium ion polymer battery, as a result of the breakdown of the SEI layer. The results from this study indicate that raising the state of charge (SOC) increases the rate of the electrolyte decomposition side reaction that resulted in formation of a thick deposit layer at the electrolyte/electrolyte interface. This deposit layer contains lithium that can no longer participate in the reversible electrochemical reaction. In addition, at high cycling potential and charge rates the amount of lithium in the graphite after complete cell discharge increased due to the entrapment of lithium in the graphite. The amount of irreversible capacity loss for the batteries cycled at high potential and current correlates with the amount of trapped lithium in the graphite and the growth of the deposit layer thickness at the electrode/electrolyte interface.
WINDS is an international, interactive workshop designed to explore the fundamental properties of nanoscale heterostructures and potential device applications. This workshop covers a spectrum of nanoscale science, emerging materials, and device technologies, including 2-D materials, topological systems, and advanced heterostructures. WINDS itself began as an outgrowth of the successful Advanced Heterostructures Workshop, which has a long history dating from the 1980s. In 2008 the name changed from AHW to WINDS in order to recognize the importance of nanotechnology in general, and the applications to devices and systems.
A two-dimensional two-phase mass transport model for liquid-feed direct methanol fuel cells (DMFCs) is presented in this paper. The fluid flow and mass transport across the membrane electrode assembly (MEA) is formulated based on the classical multiphase flow theory in the porous media. The modeling of mass transport in the catalyst layers (CLs) and membrane is given more attentions. The effect of the two-dimensional migration of protons in the electrolyte phase on the liquid flow behavior is considered. Water and methanol crossovers through the membrane are implicitly calculated in the governing equations of momentum and methanol concentration. A modified agglomerate model is developed to characterize the microstructure of the CLs. A self-written computer code is used to solve the inherently coupled differential governing equations. Then this model is applied to investigate the mechanisms of species transport and the distributions of the species concentrations, overpotential and the electrochemical reaction rates in CLs. The effects of radius and overlapping angle of agglomerates on cell performance are also explored in this work.
The aim of this study was to examine the effect of cooling rate on the cellular growth of a Pb–0.85wt%Sb alloy and to evaluate the influences of cell size and of the corresponding macrosegregation profile on the resultant corrosion behavior. In order to obtain the as-cast samples a water-cooled unidirectional solidification system was used. Such experimental set-up has permitted the development of a clear cellular structural array even for relative high cooling rates and has allowed a wide range of solidification conditions to be analyzed. Macrostructural and microstructural aspects along the casting were characterized by optical microscopy and scanning electron microscope (SEM) techniques. The electrochemical impedance spectroscopy technique and potentiodynamic curves (Tafel extrapolation) were used to analyze the corrosion resistance of samples collected along the casting length and immersed in a 0.5M H2SO4 solution at 25°C. It was found that the corrosion rate decreases with increasing cell spacing and that the pre-programming of microstructure cell size can be used as an alternative way to produce as-cast components of Pb–Sb alloys, such as battery grids, with better corrosion resistance.
Degradation of a high capacity prismatic LiFePO4 cell with deep cycling at elevated temperature of 50°C is studied by electrochemical impedance spectroscopy as well as capacity and power fading characterization at different test temperatures (45, 25, 0 and −10°C). Capacity fade after 600 cycles is 14.3% at 45°C and 25.8% at −10°C. There is little power fade at 45°C after 600 cycles, whereas the power fade after 600 cycles is 61.6% and 77.2%, respectively, at 0 and −10°C. The capacity and power fade evidently becomes more severe at lower temperature. In particular, the power fade at low temperatures (e.g., 0 and −10°C) rather than capacity loss is a major limitation of the LiFePO4 cell. The primary mechanism for capacity fade is loss of cyclable lithium in the cell resulting from lithium-consuming solid electrolyte interphase (SEI) layer growth and side reactions. The increased interfacial resistance (R w) due to the catalytic growth of SEI layer on the graphite anode and increased electrolyte resistance are the main sources for power fade.
Previous investigations comparing auditory event-related potentials (ERPs) to words whose meanings infants did or did not comprehend, found bilateral differences in brain activity to known versus unknown words in 13-month-old infants, in contrast with unilateral, left hemisphere, differences in activity in 20-month-old infants. We explore two alternative explanations for these findings. Changes in hemispheric specialization may result from a qualitative shift in the way infants process known words between 13 and 20 months. Alternatively, hemispheric specialization may arise from increased familiarity with the individual words tested. We contrasted these two explanations by measuring ERPs from 20-month-old infants with high and low production scores, for novel words they had just learned. A bilateral distribution of ERP differences was observed in both groups of infants, though the difference was larger in the left hemisphere for the high producers. These findings suggest that word familiarity is an important factor in determining the distribution of brain regions involved in word learning. An emerging left hemispheric specialization may reflect increased efficiency in the manner in which infants process familiar and novel words.
The design, development and deployment of autonomous sustainable ocean platforms for exploration and monitoring can provide researchers and decision makers with valuable data, trends and insights into the largest ecosystem on Earth. Although these outcomes can be used to prevent, identify and minimise problems, as well as to drive multiple market sectors, the design and development of such platforms remains an open challenge. In particular, energy efficiency, control and robustness are major concerns with implications for autonomy and sustainability. Rigid wingsails allow autonomous boats to navigate with increased autonomy due to lower power consumption and increased robustness as a result of mechanically simpler control compared to traditional sails. These platforms are currently the subject of deep interest, but several important research problems remain open. In order to foster dissemination and identify future trends, this paper presents a survey of the latest developments in the field of rigid wing sailboats, describing the main academic and commercial solutions both in terms of hardware and software.
Here we report on the direct deposition of large quantities of highly porous carbon nanotube networks onto a carbon fibre paper support; subsequently utilised as the anode in a Li-ion battery application showing improved long-term performance and chemical stability with a significant fully reversible capacity of 546 mAh g−1.
This paper provides a study on the characterizations of large format lithium ion battery cells exposed to extreme high temperature but without thermal runaway. A unique test is set up: an extended volume-accelerating rate calorimetry (EV-ARC) test is terminated at a specific temperature before thermal runaway happens in the battery. The battery was cooled down after an EV-ARC test with early termination. The performances of the battery before and after the EV-ARC test are investigated in detail. The results show that (a) the melting point of the separator dictates the reusability of the 25 Ah NCM battery after a near-runaway event. The battery cannot be reused after being heated to 140 °C or higher because of the exponential rise in ohmic resistance; (b) a battery can lose up to 20% of its capacity after being heated to 120 °C just one time; (c) if a battery is cycled after a thermal event, its lost capacity may be recovered partially. Furthermore, the fading and recovery mechanisms are analyzed by incremental capacity analysis (ICA) and a prognostic/mechanistic model. Model analysis confirms that the capacity loss at extremely high temperature is caused by the increase of the resistance, the loss of lithium ion (LLI) at the anode and the loss of active material (LAM) at the cathode.
This paper reports a phase-field modeling (PFM) study of lithium (Li) electrodeposition process in Li‒metal battery (LMB) to explain its physics and morphology. Three regimes are investigated: Li filaments evolution, Li bush-like structure evolution and the transition between Li filaments and bush-like morphologies. The model takes into consideration the effect of solid electrolyte interface (SEI) on Li electrodeposits evolution. Also, an important new element of the model is the capability to represent the directional diffusion of Li by implementing diffusion tensor of Li-ions in the electrolyte, thus, allowing to simulate Li filaments root growth. In addition, an elastic deformation energy of the Li solid phase is included in the free energy functional of the PFM, which allows for monitoring the stress field and its influence on Li filaments/bush-like structure evolution. In particular, a significant stress is observed at the root of the Li electrodeposits, which can support the development of the experimental strategies to suppress their formation by lowering the stress field. Thus, the present study, in addition to improving the fidelity of the PFM of Li electrodeposition, identifies critical regimes of Li filaments growth and splitting, allowing for a more profound understanding of their influence on battery performance.
Investigations on the fast capacity loss of Lithium-ion batteries (LIBs) have highlighted a rich field of mechanical phenomena occurring during charging/discharging cycles, to name only a few, large deformations coupled with nonlinear elasticity, plastification, fracture, anisotropy, structural instability, and phase separation phenomena. In the last decade, numerous experimental and theoretical studies have been conducted to investigate and model these phenomena. This review aims, on one hand, at a comprehensive overview of the approaches for modeling the coupled chemo-mechanical behavior of LIBs at three different scales, namely the particle, the electrode, and the battery cell levels. Focus is thereby the impact of mechanics on the cell performance and the degradation mechanisms. We point out the critical points in these models, as well as the challenges towards resolving them. Particularly, by outlining the milestones of theoretical and numerical models, we give a step-by-step instruction to the interested readers in both electrochemical and mechanical communities. On the other hand, this review aims to facilitate the knowledge transfer of mechanically coupled modeling to the study of all-solid-state batteries, where the mechanical issues are expected to play even more diverse and essential roles due to the additional mechanical constraintimposed by the solid electrolytes.
Solar and wind energy are considered as promising electrical generating sources. These renewable energies are omnipresent, with free access, and a friendly environmental impact. Their integration remains technically and economically advantageous for electrical generation in isolated areas (IS). In several cases, the separate use of solar and wind energy sources may result in considerable over-sizing, which makes the single renewable energy sources in implementation very costly. It is found that the use of one of the optimization sizing techniques could help to guarantee the maximum power reliability and the minimum system cost for the future hybrid implementation. Moreover, a remarkable interest is manifesting for the use of solar and wind renewable energy sources (RES), which provide a realistic form of electrical generation in isolated areas. This paper provides an updated literature review, of the most applied method and techniques used in sizing and optimization of PV-Wind based hybrid system (PWHS) for an isolated area aiming to reach the best compromise between power reliability and hybrid system costs. Furthermore, this work discusses a comparison of the most common topologies used for the implementation of PWHS, then, presents a mathematical model of the hybrid system components with an emphasis on the importance of power reliability and system cost, Finally, provides an extensive analysis of software tools and algorithm approach used in sizing optimization.
Inadequate dosimetry is often the fundamental problem in much of the controversial research dealing with radiation effects on free-ranging wildlife. Such research is difficult because of the need to measure dose from several potential pathways of exposure (i.e., internal contamination, external irradiation, and inhalation). Difficulties in quantifying external exposures can contribute significantly to the uncertainties of dose-effect relationships. Quantifying an animal's external exposure due to spatial–temporal use of habitats that can vary by orders of magnitude in radiation levels is particularly challenging. Historically, wildlife dosimetry studies have largely ignored or been unable to accurately quantify variability in external dose because of technological limitations. The difficulties of quantifying the temporal–spatial aspects of external irradiation prompted us to develop a new dosimetry instrument for field research. We merged two existing technologies [Global Positioning Systems (GPS) and electronic dosimeters] to accommodate the restrictive conditions of having a combined unit small enough to be unobtrusively worn on the neck of a free-ranging animal, and sufficiently robust to withstand harsh environmental conditions. The GPS–dosimeter quantifies the spatial and temporal variation in external dose as wildlife traverse radioactively contaminated habitats and sends, via satellites, an animal's location and short term integrated dose to the researcher at a user-defined interval. Herein we describe: (1) the GPS–dosimeters; (2) tests to compare their uniformity of response to external irradiation under laboratory conditions; (3) field tests of their durability when worn on wildlife under natural conditions; and (4) a field application of the new technology at a radioactively contaminated site. Use of coupled GPS–dosimetry will allow, for the first time, researchers to better understand the relationship of animals to their contaminated habitats and better assess animal responses to the stress of radiological exposures.
Solid polymer electrolytes consisting of poly(propylene glycol) diacrylate and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were deposited onto Cu2O-coated 3D Cu nano-pillars through cathodic electropolymerization. Electropolymerization, using constant and pulsed current techniques, was used to produce polymer coatings directly onto 3D substrates with thicknesses down to nano-scale dimensions. SEM confirmed that pulsed current deposition is comparatively beneficial for producing uniform and conformal electrolyte coatings along the nano-pillar structure. ATR/FTIR studies of the electropolymerized electrolytes showed that the degree of polymerization in the electrolyte can be increased by a heating treatment after synthesis. XPS analysis confirmed the presence of co-deposited LiTFSI salt in the polymer layer during electropolymerization. The ionic conductivity of the obtained electrolytes was characterized by EIS and is in the order of 10−6 S cm−1 at room temperature. This work demonstrates that the electrolyte coated on the nano-pillar electrodes may serve as a template for further deposition of electrode materials for the assembly of 3D-microbattery whole-cells.
The development of competitive Na- and Mg-ion batteries (NIBs and MIBs) with performance comparable to Li-ion batteries is hindered by the major challenge of finding advanced electrode materials. In this work, nanostructured TiS2 electrodes including nanosheets, nanoribbons and nanotubes are shown by first principles calculations to achieve improved Na and Mg ion diffusion as compared with the bulk phase. Comparative studies between Li, Na, and Mg reveal that the diffusion kinetics of Na ions would especially benefit from the nanostructure design of TiS2. More specifically, the Na ion diffusivity turns out to be considerably higher than Li ion diffusivity, which is opposite to that observed in bulk TiS2. However, in the case of Mg ions, fast diffusion is still beyond attainment since a relatively high degree of interaction is expected between Mg and the S atoms. Edge-induced modifications of diffusion properties appear in both Na and Mg ions, while the mobility of Li ions along the ribbon edges may not be as appealing. Effects of the curvature of nanotubes on the adsorption strength and ion conductivity are also explored. Our results highlight the nanostructure design as a rich playground for exploring electrodes in NIBs and MIBs.