batterydata/paper-abstracts huggingface dataset:
Lithium-ion batteries suffer from inherent thermal limitations (i.e., capacity fade and thermal runaway); thus, it is critical to understand heat generation experienced in the batteries under normal operation. In the current study, reversible and irreversible electrochemical heat generation rates were measured experimentally on a small commercially available C/LiFePO4 lithium-ion battery designed for high-rate applications. The battery was tested over a wide range of temperatures (10–60 °C) and discharge and charge rates (∼C/4–5C) to elucidate their effects. Two samples were tested in a specially designed wind tunnel to maintain constant battery surface temperature within a maximum variation of ±0.88 °C. A data normalization technique was employed to account for the observed capacity fade, which was largest at the highest rates. The heat rate was shown to increase with both increasing rate and decreasing temperature, and the reversible heat rate was shown to be significant even at the highest rate and temperature (7.4% at 5C and 55 °C). Results from cycling the battery using a dynamic power profile also showed that constant-current data predict the dynamic performance data well. In addition, the reversible heat rate in the dynamic simulation was shown to be significant, especially for charge-depleting HEV applications.
Objective It has been shown that a new procedure (implicit function as squashing time, IFAST) based on artificial neural networks (ANNs) is able to compress eyes-closed resting electroencephalographic (EEG) data into spatial invariants of the instant voltage distributions for an automatic classification of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) subjects with classification accuracy of individual subjects higher than 92%. Methods Here we tested the hypothesis that this is the case also for the classification of individual normal elderly (Nold) vs. MCI subjects, an important issue for the screening of large populations at high risk of AD. Eyes-closed resting EEG data (10–20 electrode montage) were recorded in 171 Nold and in 115 amnesic MCI subjects. The data inputs for the classification by IFAST were the weights of the connections within a nonlinear auto-associative ANN trained to generate the instant voltage distributions of 60-s artifact-free EEG data. Results The most relevant features were selected and coincidently the dataset was split into two halves for the final binary classification (training and testing) performed by a supervised ANN. The classification of the individual Nold and MCI subjects reached 95.87% of sensitivity and 91.06% of specificity (93.46% of accuracy). Conclusions These results indicate that IFAST can reliably distinguish eyes-closed resting EEG in individual Nold and MCI subjects. Significance IFAST may be used for large-scale periodic screening of large populations at risk of AD and personalized care.
Current literature on the roles of α-, β-carotene and β-cryptoxanthin in neurocognitive function has largely focused on preventing cognitive decline in older people, and less on neuro-development in children. We examined the relations of maternal plasma carotenoids concentrations with offspring cognitive development up to age 4.5 years in the Growing Up in Singapore Towards healthy Outcomes mother–offspring cohort study.
LiFePO4 as a cathode material for rechargeable lithium batteries was prepared by hydrothermal process at 170°C under inert atmosphere. The starting materials were LiOH, FeSO4, and (NH4)2HPO4. The particle size of the obtained LiFePO4 was 0.5μm. The electrochemical properties of LiFePO4 were characterized in a mixed solvent of ethylene carbonate and diethyl carbonate (1:1 in volume) containing 1.0moldm−3 LiClO4. The hydrothermally synthesized LiFePO4 exhibited a discharge capacity of 130mAhg−1, which was smaller than theoretical capacity (170mAhg−1). The annealing of LiFePO4 at 400°C in argon atmosphere was effective in increasing the discharge capacity. The discharge capacity of the annealed LiFePO4 was 150mAhg−1.
The innate immunity utilizes a battery of broad-spectrum antibacterial cationic polypeptides (3–5 kDa), among them defensins. In humans, defensins are the first line of defense against pathogens and their expression has been implicated in several diseases. The antibacterial activity of defensins is generally ascribed to their overall positive charge, which enables them to disrupt bacterial membrane integrity and function, but their active surface has not been fully elucidated. To perform structural and functional assays, an efficient, high-yield, easy-to-use expression and purification system must be established. Up to now, most efforts to obtain larger quantities of active recombinant defensins have been only moderately successful. Herein, we report the establishment of an efficient, high-yield expression and purification system for human defensin 5 (HD-5). Using site-directed mutagenesis, we pinpoint several arginine residues and Y27 as important for HD-5 antibacterial activity. Our expression and purification system can be harnessed for structure/activity relationship studies of defensins in particular and small polypeptides in general.
Antimony-carbon-graphene fibrous composites were prepared by the electrospinning/spray process as freestanding anodes for sodium-ion batteries. Antimony nanoparticles distribute in conductive carbonized polymer fibers and graphene flakes. The unique structure prevents the aggregation of the antimony nanoparticles and buffers the mechanical stress from volume change of antimony during repeated alloying/de-alloying process. The composites demonstrated an excellent electrochemical performance as anode material for sodium-ion batteries, with a reversible capacity of 274mAh/g after 100 charge-discharge cycles at a current density of 100mA/g.
Electrochemically active organic materials are emerging as low cost, naturally abundant and sustainable alternatives to their metal-based counterparts. However, their usage in energy storage systems is mainly hindered by their poor conductivity, which results in capacitance fade upon cycling. Here, we report a redox-active xerogel composed of 2,5-dimethoxy-1,4-benzoquinone (DMQ) decorated on reduced graphene oxide (rGO) sheets via a hydrothermal method as a high capacitance and long cycle life pseudocapacitive electrode. DMQ not only provided stable redox-active centers but also served as a spacer to avoid rGO sheets aggregation and led to a three-dimensional (3D) hierarchical electrode architecture. When a binder-free 50 μm thick rolled film was tested as a pseudocapacitive electrode, it exhibited an excellent capacitance of 650 F g−1 at 5 mV s−1 (780 F cm−3) in 1 M sulfuric acid, outperforming a large number of reported organic and inorganic electrodes. Most importantly, optimized electrodes showed an excellent capacitance retention of 99% after 25000 cycles at 50 mV s−1. Density functional theory (DFT) calculations are further used to understand the charge storage mechanism, the preferred orientation of the adsorbed molecules, charge density distribution and density of states. Our combined experimental and theoretical findings demonstrate that the careful selection of the conductive substrate, electrode architecture and organic molecules plays a crucial role in achieving high capacitance and long cycling performance.
Layered Li transition metal oxides are widely used as active materials for the positive electrode of Li-ion rechargeable batteries, where intercalation of Li in the metal oxide is a fundamental phenomenon that determines the performance of the batteries. The intercalation process is significantly affected by the crystal anisotropy and grain boundaries, particularly for all-solid-state thin film batteries. Therefore, to improve the batteries, a thorough understanding of the intercalation process on the nanometer length scale is essential. To this end, we have proposed phase-field models for calculating the relation between the realistic polycrystalline microstructure and the apparent Li diffusion coefficient. A crystallographic orientation was randomly allocated to each crystal grain in a two-dimensional polycrystalline microstructure. The simulation results show that the apparent Li diffusivity is sensitive to the diffusivity of the grain boundaries, the spatial distribution of the crystal orientation for each grain, and the grain size. The diffusivity of a small-grained structure is determined by the properties of the grain boundary. On the other hand, the diffusivity of a large-grained structure depends considerably on the relative orientation angle between neighboring grains, even when the Li conductivity of the grain boundary is large.
Atomic layer deposition (ALD) technology consisting of periodically repeated series of self-limited surface reactions is a CVD technique for the well-controlled deposition of inorganic layers with thickness in the nanometer scale which has been widely used in the semiconductor industry. In this study, a novel process to fabricate TiO2 nano-layer with high uniformity by ALD on the graphite negative electrode of lithium battery is reported. We found that under accurate thickness control, a TiO2 plated graphite electrode shows better performance in cycle life, compared with the pristine graphite. Electrochemical impedance spectroscopy (EIS) results showed that after 60 cycles, the cell resistance of the TiO2 plated electrode decreased, while that of normal graphite electrode increased significantly. The enhanced performance of the electrode may be attributed to the TiO2 plating, which suppressed the increase of resistance during the prolonged cycle.
The effect of the application of pressure during the preparation of composite flaky synthetic graphite anodes and LiCoO2 cathodes on their electrochemical behavior in Li insertion and de-insertion processes was studied using voltammetry, chronopotentiometry, electrochemical impedance spectroscopy (EIS), and ex situ AFM imaging. Unpressurized graphite electrodes reach a higher capacity and have faster kinetics than the same electrodes compressed or rolled at 5×103 kgcm−3. In contrast, the performance of rolled or compressed LiCoO2 electrodes in terms of capacity and kinetics was better than the performance of the unpressed electrodes. AFM imaging of pristine and cycled electrodes demonstrated a pronounced effect of pressure on the morphology of graphite electrodes, whereas the impact of pressure on the morphology of LiCoO2 electrodes was found to be much less pronounced. It was concluded that compressing graphite electrodes has an adverse effect on the contact between the active mass and ions in solution, while compressing LiCoO2 electrodes does not adversely affect the contact between solution species and the active mass, but rather, improves inter-particle electrical contact.
In this work, 4-(Trifluoromethyl)-benzonitrile (4-TB) is used as a novel electrolyte additive for LiNi0.5Mn1.5O4 cathode of high voltage lithium ion battery. Charge–discharge tests show that the cyclic stability of LiNi0.5Mn1.5O4 is significantly improved by using 0.5 wt.% 4-TB. With using 4-TB, LiNi0.5Mn1.5O4 delivers an initial capacity of 133 mAh g−1 and maintains 121 mAh g−1 after 300 cycles with a capacity retention of 91%, compared to the 75% of that using base electrolyte (1 M LiPF6 in ethylene carbonate(EC)/dimethyl carbonate(DMC)). The results from linear sweep voltammetry, density functional theory calculations, electrochemical impedance spectroscopy, scanning electron microscope, energy dispersive spectroscopy, Fourier transform infrared, and inductively coupled plasma, indicate that 4-TB has lower oxidative stability than EC and DMC, and is preferentially oxidized on LiNi0.5Mn1.5O4 forming a low-impedance protective film, which prevents the subsequent oxidation decomposition of the electrolyte and suppresses the manganese dissolution from LiNi0.5Mn1.5O4.
We demonstrate the synthesis of order-aligned Mn3O4 nanostructures by electrochemically depositing Mn3O4 on a pre-fabricated Cu nanowire array current collector. When used as an electrode for lithium-ion batteries, it exhibits a capacity up to 637 and 494 mA h g−1 after 100 cycles at a current rate of 10 C and 20 C (10 C = 9.4 A g−1), respectively. The excellent cycling performance and superior rate capability can be attributed to the good electrical contact, fast electron transport and good strain accommodation of the order-aligned nanostructured electrodes. The relationship between the thickness of the Mn3O4 film and its electrochemical performance has also been investigated.
The cycle life of lithium-ion batteries was investigated using a modified USABC electric vehicle testing protocol designed to simulate the effect of a hybrid energy-storage system (ultracapacitor and battery) in a plug-in hybrid electric vehicle. A side-by-side comparison of battery capacity and impedance changes with and without the effect of the ultracapacitor was performed. Calendar-life degradation effects were corrected for using control cells. The battery’s rate of cycle-related capacity degradation decreased by a factor of 2 and rate of cycle-related impedance degradation, by a factor of 5.9 when exposed to the ultracapacitor-modified profile. The modified profile avoids exposure to regeneration energy and reduces maximum voltage of the battery.
We report two autopsy cases of siblings with adult-onset autosomal dominant leukodystrophy characterized by destruction of cerebral white matter, large numbers of axonal spheroids and pigmented glia in the fronto-temporal lobes. Both patients presented with motor and cognitive symptoms and aphasia, 2–3 years before death. At autopsy, the brain showed brown coloration and decreased volume of white matter in the frontal and temporal lobes as well as corpus callosum. Microscopically, marked loss of myelin and axons and abundant axonal spheroids without apparent neuronal loss were observed in the frontal and temporal lobes, which was consistent with hereditary diffuse leukodystrophy with spheroids (HDLS). In addition, glial cells, most consistent with macrophages and containing pigments that were stained by Sudan III and PAS, were found in the white matter lesions. The present cases showed overlapping features with HDLS and pigmentary type of orthochromatic leukodystrophy, suggesting that the pathomechanisms of these two diseases are closely related.
In this paper, nickel–cobalt oxides/carbon nanotube (CNT) composites were prepared by adding and thermally decomposing nickel and cobalt nitrates directly onto the surface of carbon nanotube/graphite electrode to form nickel and cobalt oxides. Carbon nanotubes used in this paper were grown directly on graphite substrate by chemical vapor deposition technique. The capacitive behavior of nickel–cobalt oxides/CNT electrode was investigated by cyclic voltammetry and galvanostatic charge–discharge method in 1M KOH aqueous solutions. The results show that nickel–cobalt oxides/CNT composite electrode has excellent charge–discharge cycle stability (0.2% and 3.6% losses of the specific capacitance are found at the 1000th and 2000th charge–discharge cycles, respectively) and good charge–discharge properties at high currrent density. Additionally, the effect of Ni/Co molar ratio on specific capacitance of the composite electrode was investigated and the highest specific capacitance (569Fg−1 at 10mAcm−2) is obtained at Ni/Co molar ratio=1:1.
Silicon is an ideal candidate anode material for Li-ion batteries (LIBs). However, it suffers from rapid capacity fading due to large volume expansion upon lithium insertion. Herein, we design and fabricate highly stable carbon coated porous Mg2Si intermetallic anode material using facile mechano-thermal technique followed by carbon coating using thermal vapour deposition (TVD), toluene as carbon source. The electrode exhibits an excellent first reversible capacity of 726 mAh g−1 at a rate of 100 mA g−1. More importantly, the electrode demonstrates high rate capability (380 mAh g−1 at high rate of 2 A g−1) as well as high cycle stability, with capacity retentions of 65% over 500 cycles. These improvements are attributable to both Mg supporting medium and the uniform carbon coating, which can effectively increase the conductivity and electronic contact of the active material and protects large volume alterations during the electrochemical cycling process.
This Review highlights recent structure–function insights that inform diverse pharmacologic strategies for direct targeting of BAX to alternatively reactivate or inhibit apoptosis in diseases of pathologic cell survival or premature cellular demise.
Cobalt nanoparticles on an amorphous Si3N4 matrix were synthesized by direct ball-milling of Co and Si3N4 powders for an improvement of their electrochemical performance. The microstructure, morphology and chemical state of the ball-milled Co–Si3N4 composites are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of Co–Si3N4 composites was investigated by galvanostatic charge–discharge process and cyclic voltammetry (CV) technique. It is found that metallic Co nanoparticles of 10–20nm in size are highly dispersed on the amorphous inactive Si3N4 matrix after the ball-milling. The composite with a Co/Si molar ratio of 2/1 shows the optimized electrochemical performance, including discharge capacity and cycle stability. The formation of Co nanoparticles with a good reaction activity is responsible for the discharge capacity of the composites. The reversible faradic reaction between Co and β-Co(OH)2 is dominant for ball-milled Co–Si3N4 composite. The surface modification of the hydrogen storage PrMg12–Ni composites using Co–Si3N4 composites can enhance the initial discharge capacity based on the hydrogen electrochemical oxidation and Co redox reaction.
This paper describes an investigation of single-degree-of-freedom models for large mass impact on composite sandwich laminates. The stiffness parameters of the models are derived from the results of three-dimensional quasi-static contact analyses of a rigid sphere indenting a multi-layer sandwich laminate. Energy dissipating elements are incorporated into the models to account for material damage. The validity of the models is examined through comparisons with experimental force history results of impact on six different core and face sheet configurations. It is found that a Maxwell element with the nonlinear spring in series with a viscous damper element best models the impact phenomenon for this boundary condition controlled impact. The damping parameters for each type of laminate analyzed, although initially determined empirically, are found to have a unique relationship to the energy dissipated at the time of maximum contact force. With this relationship known, the damping parameter can be determined a priori to accurately predict the peak contact force and contact duration for these foam and honeycomb sandwich panels.
The electrical double-layer and electrochemical characteristics at the nanoporous carbon|acetone, acetonitrile, γ-butyrolactone and propylene carbonate interfaces with addition of (C2H5)3CH3NBF4 electrolyte have been studied by cyclic voltammetry and electrochemical impedance spectroscopy methods. The region of ideal polarizability, values of series and parallel capacitances, pore resistance and other characteristics have been established. Analysis of complex impedance plane plots shows that the nanoporous carbon|1 M (C2H5)3CH3NBF4 electrolyte interface can be simulated by an equivalent circuit, in which the two parallel conduction parts in the solid and liquid phases are interconnected by the double-layer capacitance in parallel with the complex admittance of hindered reaction of the charge transfer process or of the partial charge transfer (i.e., adsorption stage limited) process. The values of the characteristic frequency depend on the electrolyte composition (i.e., on the solvent viscosity and dielectric constant) and on the electrode potential (i.e., on the Gibbs adsorption energy of the solvent molecules and ions at the surface of the nanoporous carbon electrode dependent on the electrode potential). The modified combined Frumkin–Melik-Gaikazyan and Randles-like equivalent circuit, combined Voigt and Frumkin–Melik-Gaikazyan and Newman et al. models have been used for the simulation of the complex impedance plane plots.
The LiCoO2/mesocarbon microbeads (MCMB) batteries are over-discharged to 102% DOD, 105% DOD and 115% DOD, respectively, then are fully charged and cycled 1000 times at 0.6 C with 30% DOD. The capacity fading mechanism during long-term cycling of over-discharged batteries is analyzed by electrochemical and physical characterization. No remarkable difference is found on the morphology of LiCoO2 material from SEM. However, copper is detected on anode over-discharged to 115% DOD by EDS and XRD. The structures of LiCoO2 and MCMB materials have almost no change according to the result of XRD test. The performance of MCMB material can be degraded by over-discharge, however the LiCoO2 material still keeps good performance. The capacity of MCMB electrode is improved after being washed with water to remove the SEI film, indicating that the capacity loss of MCMB electrode is mainly attributed to the increase of SEI film. The capacity deterioration of over-discharged battery is mainly caused by the dissolution of copper current collector and the deposition of Cu on the surface of anode during the following charging process. The copper deposited on the surface of anode can hinder the lithium intercalation into/de-intercalation from the anode and promote the increase of SEI film.
The layered oxysulfide LiNiS y O2−y compounds were synthesized and characterized to investigate the effect of sulfur on the electrode performance of LiNiO2. LiNiO2 precursors were first synthesized by a sol-gel method using adipic acid as a chelating agent and then doped with sulfur powders by a solid-state reaction under the flow of oxygen to prepare LiNiS y O2−y compounds. Pure LiNiO2 electrode showed a gradual decrease of discharge capacity with cycle number, whereas the capacity retention rate of LiNiS y O2−y electrodes significantly improved. The initial discharge capacity of the LiNiS y O2−y cells was lower than that of LiNiO2 cell and decreased with the increasing content of sulfur substituted in LiNiS y O2−y .
With depleting reserves of traditional fuels, there is a worldwide demand for alternative energy solutions. One of the most promising developing technologies is energy storage, as it provides the benefit of capturing available energy for use at a later time. This paper gives an overview of the numerous forms of energy storage technologies under investigation and development, with a focus on thermal energy storage through adsorption. The current materials tested for adsorption energy storage capabilities are presented together with their corresponding performances. The materials with the best thermal energy storage performance presented in the literature include hybrid adsorbents, adsorbents with salt impregnations, and adsorbents with alkaline additions, which provide energy densities of 226–309kWh/m3. Furthermore, the demonstrative projects and systems that currently use this technology are presented. Although thermal energy storage using adsorption processes is not currently economically viable, with continued material development and system optimization, this technology has the potential to become competitive in the near future.