batterydata/paper-abstracts huggingface dataset:
A new reversible and high-performance potassium-selenium (K-Se) battery, using confined selenium/carbonized-polyacrylonitrile (PAN) composite (c-PAN-Se) as cathode and metallic potassium as anode, is reported in this work. The PAN-derived carbon matrix could effectively confine the small Se molecules and provide a sufficient buffer for the volume changes. The reversible formation of small-molecule trigonal Se (Se1, P3121) phase could essentially inhibit the formation of polyselenides and account for outstanding electrochemical performance. The carbonate-based electrolyte further synergistically diminishes the shuttle effect by inhibiting the formation of polyselenides in the meantime. The as-prepared K-Se battery shows a reversible capacity of 1904mAhcm−3 after 100 cycles at 0.2C and rate retention of 89% from 0.1 to 2C. In addition, the charge-discharge mechanism is also investigated via the combination of in-situ and ex-situ synchrotron X-ray diffraction (XRD), and Raman spectroscopy analysis. The results reveal that the introduction of K+ ions leads to the cleavage of C-Se bonds, the rearrangement of selenium atoms, and the final formation of the main product K2Se. Moreover, the reversible formation of trigonal Se (Se1, P3121) phase was detected in the reaction with K+. These findings not only can advance our understanding of this family of batteries, but also provide insight into chemically-bonded selenium composite electrodes, which could give guidance for scientific research and the optimization of Se and S electrodes for the K-S, Na-S, Li-S, Na-Se, and Li-Se batteries.
High capacity sodium (Na) metal anodes open up new opportunities for developing next-generation rechargeable batteries with both high power and high energy densities. However, many challenges still plagued their practical application, including low plating/stripping Coulombic efficiency (CE) and dendrite growth after repeated cycle inducing safety issue. Especially, the sodium metal is less stable in organic (i.e. carbonate-based) electrolytes than lithium metal, due to the more unstable organic solid–electrolyte interface (SEI). Herein, we report a facile technology to stabilize sodium metal anode and inhibit the growth of sodium dendrites. The in-situ ultrathin NaI SEI layer successfully endows best-performance Na/I2 metal batteries (>2200 cycles) with high capacity (210 mA h g−1 at 0.5 C) based on the conversion reaction chemistry with higher discharge voltage plateau (> 2.7 V) and lower overpotential (134 mV) due to the fast charge transfer dynamics and interfacial stability compared with pristine Na anode. The detailed theoretical calculations and experimental results elucidate that NaI layer has a much lower diffusion barrier compared to that of NaF (NaF as one the most commonly found inorganic components in Na-based SEI layer), and actually facilitates more uniform sodium deposition. This work provides a new avenue for designing low-cost, high-performance and high-safety sodium metal-iodine batteries and other metal-iodine batteries.
Symmetric paper-based supercapacitor devices containing polypyrrole (PPy)–cellulose composite electrodes and aqueous electrolytes can be charged using either potential step or constant current charging. Potential step charging provides better control of the charging and can result in significantly shorter charging times, enabling charging in 22s for devices with cell capacitances of 12.2F when charged to 0.8V. The paper-based electrode material was compatible with charging currents as large as 5.9Ag−1 due to the rapid counter ion mass transport resulting from the porous composite structure and the thin PPy coatings. The charging times were controlled by the RC time constants of the devices and the cell resistance was found to decrease with increasing electrode area. For small cells, the cell resistance was determined to a large extent by the electrolyte resistance and contact resistances, whereas the resistance of the current collectors dominated for larger cells. The specific cell capacitance was 38.3Fg−1 or 2.1Fcm−2, normalized with respect to the total electrode weight and electrode cross section area respectively, and the devices showed 80–90% capacitance retention after 10000 potential step charge and discharge cycles. These results, which demonstrate that potential step charging can be advantageous for conducting polymer based energy storage devices, are very encouraging for the development of new up-scalable paper-based energy storage devices.
The performance of an on-chip direct methanol fuel cell of monolithic design with an active-type system was improved more than 6-fold up to >100 µW by using hydrogen peroxide as an oxidant solution instead of dissolved oxygen, but the energy-loss caused by strong capillary forces required a redesign of both microchannel size and the system.
A method is presented of avoiding ambiguities in linear Kramers-Kronig validity tests due to under- and over-fitting. It is based on the observation that the parameters of the equivalent circuit model to be fitted start degenerating as soon as the model order chosen is too high and over-fitting is taking place. Hence, a measure of the degree of degeneration is introduced and from this a criterion is developed with which over-fitting can be easily detected. Furthermore, it is shown, how the developed criterion can be used to automatically find an appropriate model order for any given impedance spectrum. Hereby, unambiguous test results are obtained irrespective of the specific expertise of the operator. Due to its ease of use the so improved test can serve as a quick standard test revealing defectiveness of measured impedance spectra. The validity of the proposed strategy is demonstrated in simulations as well as on measurements of a commercial Lithium-Ion battery.
Neurostimulation enables adjustable and reversible modulation of disease symptoms, including those of epilepsy. Two types of brain neuromodulation, comprising anterior thalamic deep brain stimulation and responsive neurostimulation at seizure foci, are supported by Class I evidence of effectiveness, and many other sites in the brain have been targeted in small trials of neurostimulation therapy for seizures. Animal studies have mainly assisted in the identification of potential neurostimulation sites and parameters, but much of the clinical work is only loosely based on fundamental principles derived from the laboratory, and the mechanisms by which brain neurostimulation reduces seizures remain poorly understood. The benefits of stimulation tend to increase over time, with maximal effect seen typically 1–2 years after implantation. Typical reductions of seizure frequency are approximately 40% acutely, and 50–69% after several years. Seizure intensity might also be reduced. Complications from brain neurostimulation are mainly associated with the implantation procedure and hardware, including stimulation-related paraesthesias, stimulation-site infections, electrode mistargeting and, in some patients, triggered seizures or even status epilepticus. Further preclinical and clinical experience with brain stimulation surgery should lead to improved outcomes by increasing our understanding of the optimal surgical candidates, sites and parameters.
A high prevalence of obstructive sleep apnea (OSA) has been reported in medically refractory epilepsy patients, and there is increasing evidence that treatment of OSA in refractory epilepsy patients would reduce seizure frequency.
In this paper, an artificial neural network-based genetic algorithm (ANN-GA) model was developed for generating the sizing curve of stand-alone photovoltaic (SAPV) systems. Firstly, a numerical method is used for generating the sizing curves for different loss of load probability (LLP) corresponding to 40 sites located in Algeria. The inputs of ANN-GA are the geographical coordinates (Lat, Lon and Alt) and the LLP while the output is the sizing curve represented by C A = f ( C S ) . Subsequently, the proposed ANN-GA model has been trained by using a set of 36 sites, whereas data for 4 sites which are not included in the training dataset have been used for testing the ANN-GA model. The results obtained are compared and tested with those of the numerical method. In addition, two new regression models have been developed and compared with the conventional regression models. The results show that, the proposed exponential regression model with three coefficients presents more accurate results than the conventional regression models. A new ANN has been used for predicting the sizing coefficients for the best regression model. These coefficients can be used for developing the sizing curve in different locations in Algeria. The results obtained showed that the coefficient of multiple determination (R 2) is 0.9998, which can be considered as very promising.
First-principles calculations were carried out for the alkali (Li, Na, K) metal-graphite intercalation compounds (AM-GICs). From the calculated formation energies (ΔE) of the AM-GICs, it was determined that each Li-GIC and K-GIC were energetically stable until the high alkali metal density LiC6 and KC8. On the other hand, even the low Na density NaC16 and NaC12 are already not stable. Furthermore, the NaC8 and NaC6 are unstable. It has been experimentally reported that Na hardly intercalates into the graphite contrary to the Li and K. Our calculation results agree with these facts. In addition, based on the calculated energy barriers of the Li, Na and K ion jumps between sites in the graphite, it can be deduced that larger radius ions more smoothly diffuse in the graphite.
Developing excellent pseudocapacitive electrodes with long cycle, high areal capacity and large rate has been challenged. 3D printing is an additive manufacture technique that has been explored to construct microelectrodes of arbitrary geometries for high-energy–density supercapacitors. In comparison with conventional electrodes with uncontrollable geometries and architectures, 3D-printed electrodes possess unique advantage in geometrical shape, mechanical properties, surface area, especially in ion transport and charge transfer. Thus, a desirable 3D electrode with ordered porous structures can be elaborately designed by 3D printing technology for improving electrochemical capacitance and rate capability. In this work, a designed, monolithic and ordered multi-porous 3D Cu conductive skeleton was manufactured through 3D direct ink writing technique and coated with CuO nanosheet arrays by an in situ electro-oxidation treatment. Benefiting from the highly ordered multi-porous nature, the 3D-structured skeleton can effectively enlarge the surface area, enhance the penetration of electrolyte and facilitate fast electron and ion transport. As a result, the 3D-printed Cu deposited with electro-oxidation-generated CuO (3DP Cu@CuO) electrodes demonstrates an ultrahigh areal capacitance of 1.690 F cm−2 (38.79 F cm−3) at a large current density of 30 mA cm−2 (688.59 mA cm−3), excellent lifespan of 88.20% capacitance retention after 10,000 cycles at 30 mA cm−2 and superior rate capability (94.31% retention, 2-30 mA cm−2). This design concept of 3D printing multi-porous current collector with hierarchical active materials provides a novel way to build high-performance 3D microelectrodes.
Poly(o-ethoxyaniline) (POEA) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethoxyaniline in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The performance of POEA as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results of the potentiodynamic polarization and EIS studies demonstrate that the POEA coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.330V versus SCE more positive in aqueous 3% NaCl for the POEA coated Cu than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 140.
The performance of a newly designed, polyaniline–activated carbon, hybrid electrochemical capacitor is evaluated. The capacitor is prepared by using polyaniline as a positive electrode and activated carbon as a negative electrode. From a constant charge–discharge test, a specific capacitance of 380Fg−1 is obtained. The cycling behaviour of the hybrid electrochemical capacitor is examined in a two-electrode cell by means of cyclic voltammetry. The cycle-life is 4000 cycles. Values for the specific energy and specific power of 18Whkg−1 and 1.25kWkg−1, respectively, are demonstrated for a cell voltage between 1 and 1.6V.
The United Nations Environment Programme (UNEP) has begun a process of developing a legally binding instrument to manage emissions of mercury from anthropogenic sources. The UNEP Governing Council has concluded that there is sufficient evidence of significant global adverse impacts from mercury to warrant further international action; and that national, regional and global actions should be initiated as soon as possible to identify populations at risk and to reduce human generated releases. This paper describes the development of, and presents results from, a comprehensive, spatially and temporally resolved inventory of atmospheric mercury emissions from the Australian landmass. Results indicate that the best estimate of total anthropogenic emissions of mercury to the atmosphere in 2006 was 15 ± 5 tonnes. Three industrial sectors contribute substantially to Australian anthropogenic emissions: gold smelting (∼50%, essentially from a single site/operation), coal combustion in power plants (∼15%) and alumina production from bauxite (∼12%). A diverse range of other sectors contribute smaller proportions of the emitted mercury, but industrial emissions account for around 90% of total anthropogenic mercury emissions. The other sectors include other industrial sources (mining, smelting, and cement production) and the use of products containing mercury. It is difficult to determine historical trends in mercury emissions given the large uncertainties in the data. Estimates for natural and re-emitted emissions from soil, water, vegetation and fires are made using meteorological models, satellite observations of land cover and soil and vegetation type, fuel loading, fire scars and emission factors which account for the effects of temperature, insolation and other environmental variables. These natural and re-emitted sources comfortably exceed the anthropogenic emissions, and comprise 4–12 tonnes per year from vegetation, 70–210 tonnes per year from soils, and 21–63 tonnes per year from fires.
This paper builds upon the existing literature by firstly illustrating the corporate social responsibility as a general concept and secondly exploring how this model is applied to cope with economic crises in TEI. In this paper it is aimed to examine the impacts of voluntary CSR projects on TEI's both financial performance and human recourse motivations by using a semi-structured interview.
Oxidative stress-induced damage to neurons may contribute to cognitive deficits during aging and in neurodegenerative disorders. Schizophrenia has a range of cognitive deficits that may evolve from oxidative stress. Thioredoxin (TRX), a redox-regulating protein with antioxidant activity recognized as an oxidative-stress marker has recently been found to be involved in pathogenesis and psychopathology of schizophrenia. The aim of this study was to examine the association of TRX with cognitive deficits in schizophrenia. We recruited 45 chronic schizophrenic patients and 66 healthy control subjects and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and serum TRX in both groups. Schizophrenic symptoms were assessed using the positive and negative syndrome scale (PANSS). We found no significant difference in TRX levels between patients and healthy controls. Cognitive scores on the RBANS and four of its five subscales (all p<0.001) except for the Visuospatial/Constructional index (p>0.05) were significantly lower in schizophrenic patients than normal controls. For the patients, TRX was inversely associated with the Attention domain of cognitive deficits in schizophrenia; however, TRX was positively associated with Attention in controls. The significantly lower TRX levels in attention impaired schizophrenia compared to controls suggest that oxidative stress may be involved in the cognitive impairment, especially attention in schizophrenia. The differential association of TRX and cognitive performance in schizophrenia and controls may be related to the impaired oxidative stress status of schizophrenia patients.
The development and implementation of processes to store and/or transport thermal energy can be very useful to regulate the temperature of a system and to make a better use of renewable and non-renewable energy resources. It has been shown that some microencapsulated phase change materials (MPCMs) and nanoencapsulated phase change materials (NPCMs) can be used to store and/or transport thermal energy efficiently as latent heat. The composition of these materials has an effect on several properties, like their thermal conductivity, that can affect their performance. Some strategies to modify the composition of these materials developed in the last decade can be useful to improve the characteristics of these materials. A more complex composition can also enable these materials to carry out other functions, besides storing thermal energy, that can improve their performance and extend the range of possible applications of these materials. This work gathers some of these recent developments to emphasize how some of these strategies can be useful to improve the characteristics of these materials and the potential of multifunctional MPCMs and NPCMs in several applications like solar photo-thermal conversion and catalysis.
Large plastic Li-ion (PLI) cells (25–28Ah) have been fabricated for electric vehicle (EV) applications. The 28Ah cells show high specific energy (160Wh/kg), high specific power (526W/kg), excellent round-trip energy efficiency (92%), and a low self-discharge rate (6% in 30 days). A 25Ah cell of an earlier design has a good cycle-life of up to 750 cycles at 100% depth-of-discharge (DOD) to 80% of its initial capacity. Cycle-life tests of a 28Ah cell of a later design is in progress. Preliminary safety tests have also been carried out using 6Ah cells of a similar electrode design. These give very encouraging results for the development of a safe, high-energy PLI battery for EV duty.
Objective This study examined the psychiatric and neuropsychological profiles of people with psychogenic nonepileptic seizures (PNES). Methods Twenty-people who had been diagnosed with psychogenic nonepileptic seizures (PNES), but not epilepsy, were recruited into this study. A healthy control group was also recruited and was matched for age and gender. All participants underwent structured psychiatric assessment and psychometric assessment. Neuropsychological assessment was carried out using the Cambridge Neuropsychological Test Battery (CANTAB) after participants passed the Medical Symptom Validity Test (MSVT) of effort. Results One patient failed the MSVT and was excluded from the analysis. Therefore, data from 19 people with PNES and their matched healthy controls were analyzed. Compared with controls, people with PNES had significantly higher levels of depressive symptoms, anxiety symptoms, dissociative experiences, and alexithymic traits. In addition, people with PNES had impairments in spatial working memory and attention when compared with healthy controls. Conclusion To our knowledge, this is the first study to report that, compared with controls, people with PNES have abnormal cognitive functioning after controlling for effects of effort and FSIQ. People with PNES also have high levels of anxiety, depressive, and dissociative symptoms. In addition, they appear to particularly focus on health problems and show evidence of chronic emotional dysregulation. Further studies are required to replicate our results and to help clarify the pathogenic mechanisms underlying PNES.
Electrochemical studies of three types of CF x (F – fiber based, C – petroleum coke based, G – graphite based) have demonstrated different electrochemical performances in previous work, with fiber based CF x delivering superior performance over those based on petroleum coke and graphite. 13C and 19F MAS (magic angle spinning) NMR techniques are employed to identify the atomic/molecular structural factors that might account for differences in electrochemical performance among the different types of CF x . Small quantitative variations of covalent CF and LiF are noted as a function of discharge and sp3 bonded carbons are detected in discharged F type of CF x .
For Li-ion batteries, AlF3 coating has been known to modify the over-lithiated layered oxide (OLO) cathodes to produce stable cathodes, but during synthesis procedure, the environment of excess amount of Li metal and free-exposed oxygen may cause the formation of Al2O3 and LiF materials, separately. We investigated the possibility of separated coating formation of Al as Al2O3 and F as LiF from AlF3 using density functional theory calculation, which suggests a favorable binding affinity of both Al2O3 and LiF phases to the OLO surface to support the preferable formation of coating layer of Al2O3 and LiF. Meanwhile, we found the well-distributed surface modification with the coating layers and a small amount of AlF3 (<∼11 vol%) throughout various surface analyses using the well-known coating process of AlF3 formation. Importantly, during the coating process LiF led to the transformation of OLO surface from Li2MnO3 to a self-generated structure of spinel-like LiMn2O4 phase, which enhances electronic conductivity. In addition, Al2O3 plays a key role in suppressing reactions between cathode and electrolyte, leading to stable cyclability. Experimental findings suggest that the well-distributed coating layer of two materials leads to a synergic effect on the enhanced electrochemical performance for high voltage operating Li-ion batteries.
Adoption of a sintered stainless steel fiber felt was evaluated as gas diffusion backing in air-breathing direct methanol fuel cell (DMFC). By using a sintered stainless steel fiber felt as an anodic gas diffusion backing, the peak power density of an air-breathing DMFC is 24mWcm−2, which is better than that of common carbon paper. A 30-h-life test indicates that the degraded performance of the air-breathing DMFC is primarily due to the water flooding of the cathode. Twelve unit cells with each has 6cm2 of active area are connected in series to supply the power to a mobile phone assisted by a constant voltage diode. The maximum power density of 26mWcm−2 was achieved in the stack, which is higher than that in single cell. The results show that the sintered stainless steel felt is a promising solution to gas diffusion backing in the air-breathing DMFC, especially in the anodic side because of its high electronical conductivity and hydrophilicity.