batterydata/paper-abstracts huggingface dataset:
Chronoamperometric studies of the stage 2 (LiC12) to stage 1 (LiC6) transition during electrochemical insertion of Li ions into graphite electrodes showed 5 distinct domains in their current vs. time curves. A linear increase of current at the beginning of domain II and a decrease in current with time within domain IY were identified with two-dimensional instantaneous nucleation of cylindrical grains of stage 1 into stage 2, their growth and further coalescence with the formation of the continuous moving boundary. We could calculate the following characteristic parameters: the nucleation time constant, τ n =990s; the density of nucleation sites N o =2.5×108 cm−2, the velocity of the lateral growth of cylindrical nuclei, a =3.6×10−8 cms−1 and the thickness of the nucleation layer, d =0.36μm. After nucleation stage, the interphase propagates initially linearly with time and then proportionally to the square root of time (domain IV). At 30°C the speed of propagation of the moving boundary between stage 1 and stage 2, dξ/dt′, is around 1.6×10−7 cms−1. The activation energies of a, dξ/dt′ and D 1 obtained from the related Arrhenius plots were found to be 0.13, 0.19 and 0.23eV, respectively.
A S/DPAN (dehydrogenated polyacrylonitrile) composite shows promising electrode performances as a cathode material for Li-S batteries though its electric conductivity is insufficient for high rate tests. In an attempt to enhance the electric conductivity, the S/DPAN composite is attached on reduced graphene oxide (rGO) sheets via self-assembling modification. As a result, the conductivity improves to ∼10−4 S cm−1, and the S/DPAN/rGO composite thereby delivers approximately 90% of the theoretical capacity of sulphur at a rate of 0.2C (0.34 A g−1) over 700 mAh (g-S)−1 even at 2C (3.4 A g−1). We first report on the CS bond between sulphur and DPAN in a composite that maintains the bond even after an extensive cycling test, as confirmed by time-of-flight secondary-ion mass spectroscopy (ToF-SIMS). These synergistic effects enable facile electron transport such that the S/DPAN/rGO composite electrode is able to maintain superior electrode performances.
Developing desirable anode materials with 3D self-assembled structure is of paramount importance for enhancing the performance of sodium-ion batteries. Here, we report the controlled synthesis of three novel 3D VS4 nanoarchitectures: nanorods (Nanorod-VS4), nanocones and nanobelts self-assembled VS4 microspheres. When serving as anode materials for sodium-ion batteries, Nanorod-VS4 exhibits the better electrochemical performances than the latter two, delivering a high reversible capacity of 225 mAhg−1 at 0.5 Ag-1 after 200 cycles and that of 203 and 168 mAhg−1 even at 1.0 and 2.0 Ag-1, respectively. The remarkable sodium storage properties of the Nanorod-VS4 material is mainly ascribed to the synergistic effect of the self-assembled structure of radial nanorods and the preferred orientation growth along (110) planes. Moreover, the reversible insertion reaction and diffusion-dominant Na+ storage process between 0.50 and 3.00 V occurring in the Nanorod-VS4 are clearly revealed.
Lead is an environmental contaminant causing irreversible health effects in children. We used dentine lead levels as a measure of early-life lead exposure and explored determinants of lead exposure in children living in Newcastle upon Tyne, a historically industrialised UK city, in a cohort born since legislation was introduced to remove lead from petrol, paint and water pipes. The “Tooth Fairy study” cohort comprised 69 children aged 5–8 years. We collected upper deciduous incisors from children and questionnaire data from their parents in 2005. We measured lead levels in pre- and postnatal enamel and dentine using laser ablation inductively coupled plasma mass spectrometry, and assessed associations between dentine lead levels and residential, dietary, lifestyle and socio-economic characteristics. Dentine lead levels were low (mean 0.26 μg/g, range 0.06–0.77); however, we observed considerable variability in dentine lead levels within and between children suggestive of differing exposure levels and/or exposure sources across this population. Variables earlier documented to be associated with childhood lead levels were not found to be significant determinants of dentine lead levels in this study. Exposure pathways should continue to be investigated to enable targeted interventions and prevention of lead-induced health impacts in vulnerable populations.
Batteries are promising sources of green and sustainable energy that have been widely used in various applications. Battery modelling as the basis of battery management system is vital for both technology development and applications of batteries. Compared with other battery models, stochastic battery models feature high accuracy and low time consumption. Moreover, charging profile, battery behavior, and discharging profile can all be considered to optimize battery performance and usage, which is a key issue in battery usage in real life. Given the significance of stochastic modelling and the progress of battery health management, this paper reviews various aspects of related studies and developments from different fields, while identifying their corresponding merits and weaknesses. Remaining challenges are discussed, and several suggestions are offered as possible inspirations for further research.
LiMn0.8Fe0.2PO4 is becoming one of the most promising cathode materials for lithium ion batteries. However, the capacity suffers from a loss during long-term cycling, which is directly associated with Mn dissolution due to the disproportionation reaction of Mn3+. Here, we report a chemical vapor deposition (CVD) approach to modify LiMn0.8Fe0.2PO4 particles with carbon so as to minimize Mn dissolution from cathode. The deposited carbon layer not only protects LiMn0.8Fe0.2PO4 cathode from electrolyte corrosion, but also enhances the electronic/ionic conductivity owing to its higher graphitize degree. As a consequence, the electrochemical performances have a significant improvement. The capacity retention achieves 96% after 450 cycles at 1C at room temperature (25°C). Even at elevated temperature (55°C), the capacity retention also reaches at 97 % after 50 cycles at 1C rate, which is much higher than that of untreated sample (89%). Hence, the cathode material based on LiMn0.8Fe0.2PO4 encapsulated with durable carbon by CVD method represents a promising strategy for developing its long-term cycling performance through suppressing Manganese dissolution.
A hierarchically porous layered lithium-rich oxide, 0.5Li2MnO3·0.5LiMn1/3Ni1/3Co1/3O2, is synthesized by co-precipitation of metal oxalates with an assistance of a moderate polyethylene glycol (PEG2000). The morphology and crystal structure of the product are characterized by scanning electron microscope, transmission electron microscopy and X-ray diffraction, and its performance as cathode of lithium ion battery is evaluated with charge/discharge tests. It is found that the as-synthesized oxide exhibits excellent rate capability and cyclic stability: delivering an initial discharge capacity of 262 mAh g−1 at 0.1C (1C = 250 mA g−1) and 135 mAh g−1 at 4C, and possessing a capacity retention of 83% after 200 cycles at 4C. These performances can be attributed to the unique structure of the as-synthesized oxide: uniform secondary microspheres of about 10 μm, which is composed of uniform primary microparticles of about 2 μm, and hierarchically porous structure with pores distributed among primary and secondary particles. The hierarchically porous structure provides large reaction sites for lithium ion insertion/extraction and large space to buffer the volume change during cycling, leading to the excellent rate capability and cyclic stability of the as-synthesized oxide.
Background Cognitive impairment in schizophrenia is disabling, but current treatment options remain limited. Objective To meta-analyze the efficacy and safety of adjunctive antidepressants for cognitive impairment in schizophrenia. Data sources and study selection PubMed, MEDLINE, PsycINFO, and Cochrane Library databases were searched until 12/2013 for randomized controlled trials comparing antidepressant augmentation of antipsychotics with placebo regarding effects on cognitive functioning in schizophrenia. Data extraction Two authors independently extracted data. Standardized mean differences (SMDs) were calculated for continuous outcomes and risk ratios for categorical outcomes. SMDs of individual cognitive tests were pooled on a study level within domains (primary outcome) and across domains. When results were heterogeneous, random instead of fixed effects models were used. Results We meta-analyzed 11 studies (duration=8.7±3.7weeks) including 568 patients (mean age=39.5±6.9years, males=67.2%, illness duration=12.5±8.0years). Antidepressants included mirtazapine (4 studies; n=126), citalopram (2 studies; n=231), fluvoxamine (1 study; n=47), duloxetine (1 study; n=40), mianserin (1 study; n=30), bupropion (1 study; n=61), and reboxetine (1 study; n=33). Statistically significant, but clinically negligible, advantages were found for pooled antidepressants compared to placebo in executive function (Hedges' g =0.17, p=0.02) and a composite cognition score (Hedges' g =0.095, p=0.012). Depression improved with serotonergic antidepressants (p=0.0009) and selective serotonin reuptake inhibitors (p=0.009), but not with pooled antidepressants (p=0.39). Sedation was more common with pooled antidepressants (p=0.04). Conclusion Adjunctive antidepressants do not demonstrate clinically significant effects on cognition in schizophrenia patients, however, larger studies, preferably in euthymic schizophrenia patients and using full neurocognitive batteries, are needed to confirm this finding.
A solid solution of spinel (2/3)Li(Li1/3Ti5/3)O4–(1/3)Li(Ni1/2Ti3/2)O4 was prepared, and its structural/electrochemical properties were compared with Li(Li1/3Ti5/3)O4 to identify the effect of doping to the structural invariance of Li(Li1/3Ti5/3)O4. The solid solution retained the zero strain characteristic of Li(Li1/3Ti5/3)O4 during discharge/charge with an excellent cycle stability, while the rate capability was notably improved. However, a reversible broadening of the XRD peak was observed at the end of discharge, indicating some structural changes. XANES measurements showed that the oxidation state of Ti was +4 and that of Ni was +2 in the solid solution.
The effects of Zn substitution for Ni on the crystal structure and electrochemical properties of LiZn x Ni0.5-x Mn1.5O4 (x =0−0.5) are investigated. The LiZn x Ni0.5-x Mn1.5O4 samples, which were synthesized by a sol-gel method, were analyzed by X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), battery cycling test, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy (XPS). Of the compositions investigated, the LiZn0.08Ni0.42Mn1.5O4 delivered improved cycle-life and C-rate performance even at elevated temperature compared with those of Zn-free LiNi0.5Mn1.5O4. XRD and XPS results show that a thick positive electrode/electrolyte interphase film is formed on the surface of the x =0.08 electrode, which may prevent the continuous electrolyte oxidation during cycling.
Taking the advantage of hierarchical nanostructures into consideration, herein a facile and template free approach to achieve hierarchical microspheres assembled from the α-Fe2O3 nanosheet was formulated. The followed freeze-drying treatment is employed to realize the construction of nanostructured Fe2O3/graphene composite. The unique hierarchical structure of α-Fe2O3 combined with the flexible graphene layer not only effectively buffer the volume expansion during the cycling process, but also promote the transport of lithium ion and electron through three-dimensional networks when being assessed for lithium ion battery. The as-obtained composite exhibits significantly enhanced cycling stability (1850mAhg−1 after 190 cycles at the current of 300mAg−1) and superior rate performance (around 520mAhg−1 for the current of 5000mAg−1). The obtained-results illustrate that the rational designing of the nanostructured composite can result in the fast lithium insertion/de-insertion in lithium ion batteries which mimic merits seen in high-power electrochemical capacitors.
Despite the significant advances in preparing carbon-metal oxide composite electrodes, strategies for seamless interconnecting of these two materials without using binders are still scarce. Herein we design a novel method for in situ synthesis of porous 2D-layered carbon–metal oxide composite electrode. Firstly, 2D-layered Ni-Co mixed metal-organic frameworks (MOFs) are deposited directly on nickel foam by anodic electrodeposition. Subsequent pyrolysis and activation procedure lead to the formation of carbon–metal oxides composite electrodes. Even with an ultrahigh mass loading of 13.4mgcm−2, the as-prepared electrodes exhibit a superior rate performance of 93% (from 1 to 20mAcm−2), high capacitance (2098mFcm−2 at a current density of 1mAcm−2), low resistance and excellent cycling stability, making them promising candidates for practical supercapacitor application. As a proof of concept, several MOF derived electrodes with different metal sources have also been prepared successfully via the same route, demonstrating the versatility of the proposed method for the preparation of binder-free carbon–metal oxide composite electrodes for electrochemical devices.
The formation and continuous growth of a solid electrolyte interphase (SEI) layer are responsible for the irreversible capacity loss of batteries in the initial and subsequent cycles, respectively. In this article, the electron tunneling barriers from Li metal through three insulating SEI components, namely Li2CO3, LiF and Li3PO4, are computed by density function theory (DFT) approaches. Based on electron tunneling theory, it is estimated that sufficient to block electron tunneling. It is also found that the band gap decreases under tension while the work function remains the same, and thus the tunneling barrier decreases under tension and increases under compression. A new parameter, η, characterizing the average distances between anions, is proposed to unify the variation of band gap with strain under different loading conditions into a single linear function of η. An analytical model based on the tunneling results is developed to connect the irreversible capacity loss, due to the Li ions consumed in forming these SEI component layers on the surface of negative electrodes. The agreement between the model predictions and experimental results suggests that only the initial irreversible capacity loss is due to the self-limiting electron tunneling property of the SEI.
A dual functional interlayer consisted of composited two-dimensional MoS2 and graphene has been developed as an efficient polysulfide barrier for lithium-sulfur batteries (LSBs). With such a configuration, LSBs show a superior rate capacity and improved cycling capacity. The excellent electrochemical performance can be attributed to the strong bonding interactions between the MoS2/graphene interlayer and the formed lithium polysulfides (LiPSs) as well as the good electrical conductivity of the MoS2/graphene composite. The MoS2/graphene interlayer can physically block LiPSs by the graphene nanosheets and chemically suppress the dissolution of LiPSs by the polar MoS2 nanoflowers. Such a dual functional interlayer further provides a good contact with the surface of the sulfur cathode, acts as an upper current collector and greatly improves the sulfur utilization and the rate capability of LSBs.
The extent to which white matter lesions affect brain function in elderly individuals has important implications for the development of drugs to treat cognitive impairment and dementia. In this article, Frisoni et al. argue that white matter lesions can contribute to cognitive impairment in elderly individuals, although their effects are minor when compared with those of other causes of cognitive deterioration, such as Alzheimer's disease.
Polytriphenylamine (PTPAn) was chemically synthesized and tested as a cathode material for high-rate storage and delivery of electrochemical energy. It is found that the polymer has not only superior high power capability but also high energy density at prolonged cycling. At a moderate rate of 0.5C, PTPAn gives a high average discharge voltage of 3.8V and quite a high capacity of 103mAhg−1, which is very close to the theoretical capacity (109mAhg−1) as expected from one electron transfer per triphenylamine monomer. Even cycled at a very high rate of 20C, the polymer can still deliver a capacity of 90mAhg−1 at 1000th cycle with a nearly 100% coulombic efficiency. The excellent electrochemical performances of PTPAn are explained from the structural specificity of the polymer where the radical redox centers are stabilized and protected by conductive polymeric backbone, making the radical redox and charge-transporting processes kinetically facile for high-rate charge and discharge.
Objective: Changes in biochemical markers of bone formation and resorption were followed over the course of 1 year in premenopausal, perimenopausal and early postmenopausal women. Methods: Sixty-four subjects were analyzed, grouped according to their menstrual pattern, menopausal complaints and endocrinological parameters to be premenopausal (n=20), perimenopausal (n=24) or early postmenopausal (n=20). The parameters studied at four visits during the 12-month study period were the urinary pyridinium cross-links pyridinoline (PYD) and deoxypyridinoline (DPD), and N-terminal telopeptide (NTX) as bone resorption markers, as well as osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) in serum, representing bone formation. The longitudinal changes over time as well as intergroup differences were analyzed using generalized estimating equations (GEE) in connection with Wald statistics. Results: Over the course of 1 year BAP levels decreased in the late premenopausal group (P<0.05). The perimenopausal group exhibited significant changes of PYD, DPD and OC (P<0.01), NTX levels were higher than in premenopause. Postmenopausal subjects had elevated NTX values, while PYD and DPD levels remained close to the perimenopausal range. Only for OC a time effect was seen during postmenopause. Conclusions: Changes in bone turnover already begin in late premenopause, when decreased bone formation may precede increased bone resorption. The rise of NTX from late premenopause through early postmenopause indicates diagnostic sensitivity of this parameter to changes in bone metabolism induced by estrogen withdrawal. PYD and DPD do not follow this pattern, but change significantly with time during perimenopause to then remain largely unchanged in early postmenopause.
The study on the formation of lithium alloying with Bi thin layer electrode and its kinetics was carried out in 1mol/dm3 LiClO4/PC electrolyte. In situ XRD and chronopotentiometry results confirmed the formation of LiBi and Li3Bi alloy phases with the open circuit potentials of 0.830 and 0.805V, respectively. The formation of Li3Bi alloy rather than LiBi alloy was found to be responsible for the mechanical degradation of Li–Bi alloy electrode. Lithium diffusion coefficient in LiBi alloy was evaluated to be in the order of 10−13 cm2/s by ac impedance measurement. This smaller lithium diffusion coefficient in thin layer electrode than that in the common sheet electrode was attributed to the intrinsic properties of the thin layer electrode. Furthermore, a mechanism involving the adsorption process at the electrode surface was proposed for lithium alloying with bismuth.
With the desirable energy densities, Li-rich layered cathodes have attracted great attention as potential candidates for next generation Li-ion batteries (LIBs). In this context, the Li-rich layered cathode Li[Li0.2Mn0.56Ni0.17Co0.07]O2 (LMNCO) is prepared and surface modified homogeneously with Li-conductive Li2SiO3 layer via a facile co-precipitation process. It is found that the 3 wt% Li2SiO3 modified Li-rich cathode delivers a specific capacity as high as 207 mAh g−1 after 50 cycles, which results from the interplay among the electrode, Li2SiO3 coating layer and the electrolyte. Further analysis indicates that the Li2SiO3 layer could effectively balance the exfoliation of surface alkaline speciation and the dissolution of surface transition metal to generate the LiMnNiCoSiO protection layer, which will beneficial to the Li surface diffusion kinetics and the electrochemical stability of Li-rich layered materials as well.
Lithium difluoro(oxalato)borate (LiDFOB) was investigated as an electrolyte additive for high-voltage lithium-ion batteries in order to decrease the decomposition of the electrolyte. As a typical high-voltage cathode material, LiCoPO4 was tested in the LiDFOB-containing electrolyte, exhibiting higher reversible charge/discharge capacity and better cyclic stability. The effect of LiDFOB on the formation of a stable interphase film was investigated through cyclic voltammetry and X-ray photoelectron spectroscopy. LiDFOB was helpful to form a stable interphase film and passivate the cathode surface; therefore, the decomposition of the electrolyte was inhibited accordingly.
Publisher Summary This chapter deals with the technologies for coal utilization. Coal use in the United States had been primarily for iron and steel production, locomotives for transportation, and household heat. In addition, many chemicals, including medicines, dyes, flavorings, ammonia, and explosives were produced from coal. Coal is used in the industrial sector for producing steam and to a lesser extent electricity, and some chemicals are produced from coal. The chapter explores the technologies used for generating power, heat, coke, and chemicals and includes combustion, carbonization, gasification, and liquefaction, which have been referred to as the four “grand processes” of coal utilization. Advances in materials of construction, system designs, and fuel firing have led to increasing capacity and higher steam operating temperatures and pressures. In the United States, utilities typically choose between two basic pulverized coal-fired watertube steam generators: subcritical drum-type boilers with nominal operating pressures of either 1900 or 2600 psig or once-through supercritical units operating at 3800 psig advances. The chapter concludes by emphasizing on coal combustion, as this technology is the single largest user of coal.
An introduction to the various types of calorimeters is given. The requirements for precise temperature measurements with thermistors are derived. Methods and equations for accurate heat exchange corrections for isoperibol temperature-change calorimetry under various conditions are derived. The characteristics and design principles for constant temperature baths are discussed. The construction of devices for addition of reagents, of stirrers, and of calibration heaters is described.