batterydata/paper-abstracts huggingface dataset:
The influence of two types of multi-walled carbon nanotubes, pristine (MWCNTs) and carboxylated (MWCNTs–COOH), on the electrochemical performance of LiNi0.33Co0.33Mn0.33O2 (NCM)- and LiFePO4 (LFP)-based positive electrodes is investigated. Several characterization techniques, e.g., electronic conductivity measurements, galvanostatic cycling, cyclic voltammetry, electrochemical impedance spectroscopy, and SEM/EDX, were employed. The results suggest that improved electronic conductivity is not necessarily synonymous with enhanced performance. A clear dependence of both rate capability and electrode morphology on the combination of conductive additive and active material can be observed. In particular, while LFP performs better with MWCNTs–COOH, pristine MWCNTs appear to be better suited for NCM. Although the use of MWCNTs–COOH improves the connective network between the active particles for both NCM and LFP, the presence of COOH moieties appears to have a strong effect on the surface properties of the NCM-based electrodes. MWCNTs–COOH formed a shell around the active particles, which may function as a physical barrier and hinder Li+ insertion/extraction.
For improving the electrochemical performance and thermal stability, magnesium was chosen as the doping element in Li(NiCoMn)O2 cathode materials. LiNi0.6−x Mg x Co0.25Mn0.15O2 (x =0 and 0.03) were successfully synthesized via the mixing hydroxide method. These materials exhibited α-NaFeO2 structure as indicated by the XRD patterns. The intensity ratio of (003) to (104) showed that the Mg substitution could reduce the cation mixing. The pristine material exhibited the initial discharge of capacity 199mAhg−1 and remained retention of 79% after 20 cycles in the voltage range of 3–4.5V. When magnesium ions were substituted, the initial capacity was reduced due to the less active ions. However, the capacity retention was increased to 95%. Not only cycleability, but also the thermal stability was improved by Mg substitution at every delithiated state of electrodes with electrolytes. The in situ synchrotron X-ray diffraction patterns showed that the boundary of phase transition for H1 to H2 was much clearer in Mg-doped sample, indicating that the LiNi0.57Mg0.03Co0.25Mn0.15O2 material exhibited higher structural integrity. The improvements of both electrochemical retention and thermal stability were possibly attributed to the reduced cation mixing and complete structural changes.
MgMn2O4 spinel oxide has a very positive redox potential (2–3 V vs. Mg/Mg2+) and is a promising positive electrode material for Mg rechargeable batteries. However, the charge of MgMn2O4 cannot be adequately accumulated due to oxidative electrolyte decomposition resulting in poor cyclability. We have examined the effect of transition metal ion substitution in Mg spinel oxides and demonstrated that oxidative electrolyte decomposition is suppressed by replacing Mn cations in MgMn2O4 with Fe. Tetragonal MgMn2O4 spinel was converted into cubic-phase Mg(Mn1−xFex)2O4, when 20% or more of its Mn3+ ions were replaced by Fe3+ (x = 0.2, 0.4, 0.6, 0.8, 1). Mixed Mn–Fe cubic spinel oxides exhibited enhanced cyclic performance due to the suppression of oxidative electrolyte decomposition and improved structural stability. This approach provides a means of improving the electrochemical performance of Mg battery systems without requiring thermodynamically stable electrolytes.
Introduction The verb-specific impairment present in patients with motion-related neurological diseases has been argued to support the hypothesis that the processing of words referring to motion depends on neural activity in regions involved in motor planning and execution. We presented a group of Parkinson’s disease (PD) patients with an action-naming task in order to test whether the prevalence of motion-related semantic content in different verbs influences their accuracy. Methods Forty-nine PD patients and 19 healthy seniors participated in the study. All of PD participants underwent a neurological and neuropsychological assessment to rule out dementia. Subjective ratings of the motion content level of 100 verbs were obtained from 14 young voluntaries. Then, pictures corresponding to two subsets of 25 verbs with significantly different degrees of motor component were selected to be used in an action-naming task. Stimuli lists were matched on visual and psycholinguistic characteristics. Results ANOVA analysis reveals differences between groups. PD patients obtained poor results in response to pictures with high motor content compared to those with low motor association. Nevertheless, this effect did not appear on the control group. The general linear mixed model analytic approach was applied to explore the influence of the degree of motion-related semantic content of each verb in the accuracy scores of the participants. The performance of PD patients appeared to be negatively affected by the level of motion-related semantic content associated to each verb. Conclusions Our results provide compelling evidence of the relevance of brain areas related to planning and execution of movements in the retrieval of motion-related semantic content.
Lithium-sulfur (Li-S) battery with high theoretical capacity (1675 mAh g−1) and energy density (2600Whkg−1) is principally considered as an attractive alternative for state of art Li-ion batteries. In this study, a series of ternary composites were synthesized with bamboo-derived hierarchical carbon (BDC) to load S and flexible polyaniline (PANI) as a coating layer. The BDC/S composite was encapsulated by different weight percentage of PANI. The ternary PANI@BDC/S composites were characterized detailly by structural and electrochemical analysis and the results revealed that the PANI@BDC/S-20% electrode presented a thin and uniform PANI coating. As a cathode material for Li-S battery, the PANI@BDC/S-20% electrode exhibited the highest initial capacity (1463 mAh g−1 at 0.1C), outstanding long-life performance (366 mAh g−1 at 0.5C after 500cycles), excellent rate property (527 mAh g−1 at 2C). The incremented gains were mainly because thin PANI coating was polymerized along with the porous carbon walls of BDC substrate, leaving an excellent hierarchical porous microstructure. The specific structure showed great physical confinement for polysulfides, meantime, the polysulfide migration could be restricted by heteroatom (N atom) doped on the PANI backbone. The soft and stable PANI shell reduce volume expansion during cycles, providing an integrated conductive framework for enhancing the electrochemical contact between S particles and carbon substrate. More important, the modified polar interface contributed to stable SEI formation. Such a novel design of cathode material demonstrated great potential for practical applications in Li-S batteries.
Rice husks were converted into activated carbon by KOH activation, at temperatures between 400 and 900°C and used in a two-electrode supercapacitor. The rice husks contain SiO2 nano-crystals surrounded by an amorphous carbon matrix. The activated carbons maintained their size and shape after the synthesis process and the ordering degree of carbon increased at elevated temperatures. The highest BET surface area of the activated carbons was around 3145m2 g− 1. Electrochemical properties of the studied samples were measured using a two electrode cell in 6M KOH and 1.5M tetraethylammonium tetrafluoroborate in acetonitrile. The material synthesized at 800°C showed the highest gravimetric capacitance performance of 367Fg− 1and 174Fg− 1 in aqueous and organic electrolytes, respectively. In contrast to the commercial activated carbons, rice husk activated carbon (RHAC), this material showed excellent high-power handling ability and electrochemical cycle performance, after 30000 cycles the capacitive value almost remained unchanged.
Silicon is regarded as one of the most promising anode materials for Li-ion batteries owing to its high theoretical capacity (4200mAhg−1, Li22Si5), but the short cycle life mainly caused by the dramatic volume effect has hindered its practical application. To address this major issue, we report here an effective and scalable approach to fabricate a novel Si electrode via the addition of silane coupling agent, which not only connects silicon and polyacrylic acid (PAA) covalently but also crosslinks PAA, thus forming an entire 3D binding network. The dual functions of 3-amino-propyltriethoxysilane (APTES) in an electrode with 80% Si nanoparticles greatly improves the structural stability during the charge/discharge process, leading to excellent electrochemical performances, such as 1000mAhg−1 over 1200 cycles and high silicon loading of ca. 4.2mAhcm−2. Moreover, this binder system is also effective for the thick silicon/graphite electrodes towards practical application.
Sulfurized−poly(acrylonitrile) composite cathode materials provide high specific capacity, deprive the dissolution of polysulfides and shuttling effect. However, these materials have intrinsic problems such as low sulfur loading and poor rate capability at high C−rate due to the moderate conductivity of the composites. Here, we synthesize a wrapped S/rSP@SPAN composite using a dissolution−reprecipitation method followed by the thermal treatment. The idea is that the dissolution−reprecipitation of SP@PAN augments the surface area of the composite, which provides high sulfur loading and improves the composite−electrolyte contact, and conductivity of cathode material. As a result, the electrochemical performance of the as−fabricated S/rSP@SPAN cathode material yields excellent cyclability and high rate capability of 492 mAh g−1 even at a high C−rate (10 C) with high sulfur loading (54.5%).
Pain and impaired function in the cervical region are common in Air Force personnel (AFP), but evidence is limited regarding the thoracic region. This cross-sectional cohort study examined associations between cervico-thoracic pain and physical performance among Swedish AFP and explored possible differences and similarities in test performance between fighter pilots (FP), helicopter pilots (HP) and rear crew (RC).
There is a vigorous debate as to whether visual perception and imagery share the same neuronal networks, whether the primary visual cortex is necessarily involved in visual imagery, and whether visual imagery functions are lateralized in the brain. Two patients with brain damage from closed head injury were submitted to tests of mental imagery in the visual, tactile, auditory, gustatory, olfactory and motor domains, as well as to an extensive testing of cognitive functions. A computerized mapping procedure was used to localize the site and to assess the extent of the lesions. One patient showed pure visual mental imagery deficits in the absence of imagery deficits in other sensory domains as well as in the motor domain, while the other patient showed both visual and tactile imagery deficits. Perceptual, language, and memory deficits were conspicuously absent. Computerized analysis of the lesions showed a massive involvement of the left temporal lobe in both patients and a bilateral parietal lesion in one patient. In both patients the calcarine cortex with the primary visual area was bilaterally intact. Our study indicates that: (i) visual imagery deficits can occur independently from deficits of visual perception; (ii) visual imagery deficits can occur when the primary visual cortex is intact and (iii) the left temporal lobe plays an important role in visual mental imagery.
Nano-sized hollow spindle LiMnPO4 with a well-developed olivine-type structure was synthesized with the assistance of glucose in dimethyl sulfoxide (DMSO)/H2O under ambient pressure and 108°C. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images show that the LiMnPO4 particles consist of hollow spindles with a mean width of 200nm, length of 500-700nm, and wall thickness of about 30-60nm. The LiMnPO4/C nanocomposite was obtained by sintering nano-sized LiMnPO4 with glucose at 650°C under an inert atmosphere for 4h. With a coated carbon thickness of about 10 nm, the obtained composite maintained the morphology and size of the hollow spindle. The electrochemical tests show the specific capacity of LiMnPO4/C nanocomposite is 161.8mAhg−1 at 0.05C, 137.7mAhg−1 at 0.1C and 110.8mAhg−1 at 0.2C. The retention of discharge capacity maintains 92% after 100 cycles at 0.2C. After different rate cycles the high capacity of the LiMnPO4/C nanocomposite can be recovered. This high performance is attributed to the composite material's hollow spindle structure, which facilitates the electrolyte infiltration, resulting in an increased solid-liquid interface. The carbon layer covering the hollow spindle also contributes to the high performance of the LiMnPO4/C material as the carbon layer improves its electronic conductivity and the nano-scaled wall thickness decreases the paths of Li deintercalation.
There is a general consensus in the lead acid battery industry for the use of carbon additives as a functional component in the negative paste to boost the battery performance with regards to charge acceptance and cycle life especially for upcoming automotive and energy storage applications. Several mechanisms are discussed in the scientific literature and the affinity of the carbon surfaces to lead species seems to play a key role. With a set of experiments on model carbon electrodes we gave evidence to the fact that some carbon materials promote spontaneous nucleation of lead crystals. We propose a mechanism such that the carbon, as soon as in a lead containing environment, immobilizes some lead on its surface. Such immobilized lead acts as nucleation seed for the deposition of lead when a current is passed through the material. It is therefore possible to differentiate and select the carbon materials based on their ability to form nucleation seeds.
Continuous power generation from energy harvesting systems is dependent on their mechanical strength as they convert wasted mechanical energy into useful electrical energy. Here, the first generation of high strength, fiber-based energy harvesters is developed through a simple, scalable and cost-effective process. To fabricate these light yet robust energy harvesting materials, vertically aligned ZnO nanowires are grown on the fibers' surface of a woven aramid fabric. The ZnO nanostructured interface is used as a functional unit as well as a reinforcement component. The power harvesting performance of these hybrid composites is demonstrated through direct vibration examination of a fabricated cantilever beam. The fabricated hybrid composite energy harvester beam produced a high open circuit voltage of ∼125 mV root mean square (and ∼0.4 V peak-to-peak) when subjected to a cyclic base acceleration of only 1g root mean square. Moreover, assessing the structural performance of these composites revealed significant increase in the elastic modulus and tensile strength of the composites by 34.3% and 18.4%, respectively. These results indicate that integrating ZnO nanowire arrays not only provides energy harvesting capability, but also enhances the mechanical properties of the composite. This methodology can be considered as the first development of a high strength material with embedded energy harvesting and thus demonstrates multifunctional materials with improved strength and functionality.
Heat generation behaviors during charge and discharge are examined by calorimetric measurement for several lithium-ion cells that are commercially available. Heat flow from the cell shows interesting variation reflecting the characteristics of the electrode reactions. Heat generation of the cell with graphitic carbon anode draws extremely complicated curve caused by variation of stage structure of lithium intercalated graphite. The cell with hard carbon anode dissipates excess heat resulting in a voltage hysteresis between charge and discharge. In the LiCoO2 cathode, thermal behaviors due to the crystal phase transition are clearly observed.
We propose an algorithm to compute the optimal parameters of a probabilistic data propagation algorithm for wireless sensor networks (WSN). The probabilistic data propagation algorithm we consider was introduced in previous work, and it is known that this algorithm, when used with adequate parameters, balances the energy consumption and increases the lifespan of the WSN. However, we show that in the general case achieving energy balance may not be possible. We propose a centralized algorithm to compute the optimal parameters of the probabilistic data propagation algorithm, and prove that these parameters maximize the lifespan of the network even when it is not possible to achieve energy balance. Compared to previous work, our contribution is the following: (a) we give a formal definition of an optimal data propagation algorithm: an algorithm maximizing the lifespan of the network. (b) We find a simple necessary and sufficient condition for the data propagation algorithm to be optimal. (c) We constructively prove that there exists a choice of parameters optimizing the probabilistic data propagation algorithm. (d) We provide a centralized algorithm to compute these optimal parameters, thus enabling their use in a WSN. (e) We extend previous work by considering the energy consumption per sensor, instead of the consumption per slice, and propose a spreading technique to balance the energy among sensors of a same slice. The technique is numerically validated by simulating a WSN accomplishing a data monitoring task and propagating data using the probabilistic data propagation algorithm with optimal parameters.
Three techniques, i.e., pyrolysis of sucrose, spray of acetylene black, and propane vapor deposition, are adopted to coat carbon onto the surface of LiCoPO4 particles, and their effects are compared. The LiCoPO4/C composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS). The results show that the coating techniques determine the property of carbon films formed on the surface of LiCoPO4 particles, which further affect the performance of LiCoPO4. A complete and homogeneous carbon layer is the key to a high electrochemical activity and stable cycle performance. Among these LiCoPO4/C composites, the material processed via the deposition technique shows a more uniform carbon layer than that of the others, thus it exhibits a large reversible capacity of 130 mA h g−1 with favorable cyclability and rate capability in the voltage range of 3.0–5.0 V.
Epigenetics describes the study of heritable changes in gene expression that occur in the absence of a change to the DNA sequence. Specific patterns of epigenetic signatures can be stably transmitted through mitosis and cell division and form the molecular basis for developmental stage- and cell type-specific gene expression. Associations have been observed that endogenous and exogenous stimuli can change the epigenetic control of both somatic and stem cell differentiation and thus influence phenotypic behaviours and/or disease progression. In relation to drug safety, DNA methylation changes have been identified in many stages of tumour development following exposure to non-genotoxic carcinogens. However, it is not clear whether DNA methylation changes cause cancer, or arise as a consequence of the transformed state. Toxic agents could act at different levels, by directly modifying the epigenome or indirectly by altering signalling pathways. These alterations in chromatin structure may or may not be heritable but are probably reversible. That said, there is currently insufficient data to support inclusion of epigenetic profiling into pre-clinical evaluation studies. Several international collaborations aim to generate data to determine whether epigenetic modifications are causal links in disease and/or tumour progression. It will only be when an understanding of chemical mode-of-action is required that evaluation of epigenetic changes might be considered. The current toxicological testing battery is expected to identify any potential adverse effects regardless of the mechanism, epigenetic or otherwise. It is recommended that toxicologists keep a close watch of new developments in this field, in particular identification of early epigenetic markers for non-genotoxic carcinogenicity. Scientific collaborations between academia and industry will help to understand inter-individual variations in response to drug and toxin exposure to be able to distinguish between adverse and non-adverse epigenetic changes.
TiO2-coated LiMn2O4 cathode powders are prepared using an in situ spray pyrolysis process. The TiO2-coated LiMn2O4 powders have spherical aggregated structures of nanometer-sized primary particles. The mean sizes of the primary and secondary TiO2-coated LiMn2O4 powders are 55 and 880 nm, respectively. The transmission electron microscopy images of the LiMn2O4 primary particles show a single-crystalline and well-faceted structure. The single-crystalline LiMn2O4 primary particles are uniformly coated with an amorphous TiO2 layer. An immediate reaction of titanium tetraisopropoxide with oxygen forms a small flame at the exit of an alumina tube located in the center part of a quartz reactor. Sudden collisions between TiO2 vapor and submicron-sized composite powders of the Li and Mn components occur to form the TiO2-coated cathode powders. The discharge capacities of the TiO2-coated LiMn2O4 cathode powders are 126 and 109 mAh g−1 in the first and 170 cycles at a current density of 1 C. The capacity retentions of the pure and TiO2-coated LiMn2O4 powders are 69% and 86% of the initial capacity after 170 cycles.
MXene-based materials are promising electrode materials for supercapacitors. Herein, Ni2CO3(OH)2 nanosheets and/or nanoparticles are in-situ grown on the surface of two-dimensional (2D) Ti3C2 to form Ti3C2/Ni2CO3(OH)2 composites during one-pot hydrothermal processing. The uniform distribution of Ni2CO3(OH)2 on Ti3C2 is due to the electrostatic interaction between positively charged nickel ions and negatively charged Ti3C2. Importantly, the electrochemical performance of Ti3C2/Ni2CO3(OH)2 are enhanced. The 30-Ti3C2/Ni2CO3(OH)2 composite electrode exhibits a specific capacity of 173.8 mAh g−1 at 1 A g−1 and excellent cycling stability (capacity retention of 80.1% after 5000 cycles at 10 A g−1). The hybrid supercapacitor using 30-Ti3C2/Ni2CO3(OH)2 composite as positive electrode and active carbon as negative electrode delivers a high energy density of 28.2 Wh kg−1 at a power density of 374.8 W kg−1. The super performance of the composite electrode is attributed to the synergistic effects of good redox activity of Ni2CO3(OH)2 particles combined with high electronic conductivity of 2D Ti3C2. The excellent electrochemical performance of Ti3C2/Ni2CO3(OH)2 composite indicates its potential as a promising electrode material to high energy/power density energy storage devices.
This article studies the synthesis and properties of copolymers of aniline and both 2-amino (2ABSA) and 3-aminobenzenesulfonic acids (3ABSA) with a molar degree of sulfonation from 3 to 33% for 3ABSA and 10 to 43% for 2ABSA. The small segments of the sulfonic species in the polymer chain (molar fraction=0.03) confer solubility in alkaline medium (around 0.012gL−1) and good electrochemical response at pH 7.2 improving those for the unmodified polyaniline (PANI). Taking advantage of the electroactivity at physiological pH, the electrochemical response of redox couples (ferrocyanide(II)/ferricyanide(III) and ferrocene/ferrocenium) has been analysed. The electrochemical response of Cytochrome c (Cyt c) solutions has been also studied at pH 7.2 in presence and absence of ferrocene/ferrocenium species.