batterydata/paper-abstracts huggingface dataset:
Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies due to their high theoretical specific energy of 1675 mAh g−1. However, the rapid capacity degradation, mainly caused by polysulfide dissolution, remains a significant challenge prior to practical applications. In this work, a sulfur cathode modified by bifunctional nafion/γ-Al2O3 membrane has been successfully prepared, which can remarkably immobilize the polysulfides within the unique cathode structure due to its ions selectivity and absorbent capacity. A high initial discharge capacity of 1448.0 mAh g−1 can be achieved at 1C and 788.6 mAh g−1 preserved after 200 cycles, indicating a slow degradation. Furthermore, the coulombic efficiency maintains as high as 97% during cycling. The excellent electrochemical properties can be attributed to the bifunctional and stable membrane which can dramatically reduce the shuttle effect and keep integrated even after charging–discharging for 200 cycles.
Accruing evidence suggests that the cognitive deficits in very early Alzheimer's Disease (AD) are not confined to episodic memory, with a number of studies documenting semantic memory deficits, especially for knowledge of people. To investigate whether this difficulty in naming famous people extends to other proper names based information, three naming tasks – the Graded Naming Test (GNT), which uses objects and animals, the Graded Faces Test (GFT) and the newly designed Graded Buildings Test (GBT) – were administered to 69 participants (32 patients in the early prodromal stage of AD, so-called Mild Cognitive Impairment (MCI), and 37 normal control participants). Patients were found to be impaired on all three tests compared to controls, although naming of objects was significantly better than naming of faces and buildings. Discriminant analysis successfully predicted group membership for 100% controls and 78.1% of patients. The results suggest that even in cases that do not yet fulfil criteria for AD naming of famous people and buildings is impaired, and that both these semantic domains show greater vulnerability than general semantic knowledge. A semantic deficit together with the hallmark episodic deficit may be common in MCI, and that the use of graded tasks tapping semantic memory may be useful for the early identification of patients with MCI.
In situ XRD and 6 Li MAS NMR spectroscopy have been carried out during the first charge process for the layered cathode material Li[Li1/9Ni3/9Mn5/9]O2. In situ XRD results showed that the c-parameters of the Li[Li1/9Ni3/9Mn5/9]O2 material increase only slightly at the end of charge. The Mn and Ni K-edge EXAFS results revealed that this compound contains localized clusters resembling the local environments found in Li2MnO3 and lithium nickel oxide. The 6 Li MAS NMR results showed the presence of Li in the Ni2+/Mn4+ layers, in addition to the expected sites for Li in the lithium layers. All the Li ions in the transition metal layers are removed on the first charge, leaving residual lithium ions in the lithium layers.
If a physical component or a device, employed in a process fails at a certain time instant T +, but due to an event unrelated to the evolution of the process, or its mechanism, the observed survival time is called censored. Since the true survival time T might have been found to be any time instant T > T +, had the process-independent event not occurred, analysis is different from purely uncensored-data analysis. The subject matter is numerically treated for an electrochemical system by estimating its survival function, and by two-sample observation sets of cathode failure in comparing tank-flow to tubular-flow electrolyzer performance.
Al-doped LiMn2O4 cathode materials synthesized by a newly developed wet-milling method and a dry process method using a conventional solid-state reaction were evaluated physicochemically and electrochemically. In the wet-milling method, a precursor was made from the raw materials atomized by a wet milling. A good cyclic performance was obtained for the LiMn2O4 samples prepared by the wet-milling method, achieved up to 99% of retention of capacity at 50°C at the 30th cycle. The precursor obtained by the wet-milling method was well homogenous and highly reactive due to their finely ground particles, giving good crystallinity to LiMn2O4 products.
Commercialized conductive slurry consisting of polyacrylamide (PAM) and two kinds of carbon black was coated on the surface of sulfur cathode. The hybrid PAM/C coating not only physically blocks but also chemically anchors polysulfides within the cathode, confining their out-diffusion and shuttle. Besides, the flexible and highly-conductive coating layer buffers volume change of the cathode during discharge-charge process and reduces charge transfer resistance. A specific capacity of as high as ∼900mAhg−1 after 300 cycles is demonstrated for the PAM/C coated cathode, which is a significant improvement of reversible capacity and cycle capability compared to uncoated or conventional PVDF/C coated cathode.
A high capacity Li2MnSiO4/C nanocomposite cathode material with good rate performance for lithium ion batteries through a solution route has been successfully prepared. The material is able to deliver a reversible capacity of 209mAhg−1 in the first cycle, i.e. more than one electron exchange can be reversible cycled in the materials. The highly dispersion of nanocrystalline Li2MnSiO4 which was surround by a thin film of carbon was attributed to the cause of excellent performance of the materials. Ex situ XRD and IR results show that poor cycling behavior of Li2MnSiO4 might be due to an amorphization process of the materials.
This work is focused on applying structural concepts and basic chemical principles to model two N-heterocyclic lithium salts, based on trifluoromethyl substituted pyrazolide anions. An easily upscalable preparation method without difficult purification steps was also developed. In a comparative study, the physicochemical properties of the two new lithium salts were investigated, particularly the effect of an additional BF3-group at the nitrogen atom. In comparison to non-substituted lithium pyrazolide, the BF3-addition led to a strong improvement of thermal and electrochemical stability, ionic conductivity, as well as better C-rate and cycling performance. Furthermore, the anodic stability of Al current collectors was investigated and compared to commercial lithium salts, namely LiPF6 and lithium bis((trifluoromethyl)sulfonyl)imide (LiTFSI). Possible mechanisms that lead to the presented improvements are discussed.
Location awareness is a key issue to improve the development of autonomous entities that are embedded into ubiquitous computing environments. GPS seems to be the best solution to develop outdoor location systems, but the performance of these systems is not good enough to locate objects or humans within indoor environments, mainly if accuracy and precision are required. In this article we propose the use of a cheap and reliable technology as RFID to develop a passive RFID-based indoor location system that is able to accurately locate autonomous entities, such as robots and people, within a defined surface. This system is applied to solve the robot tracking problem. We include the evaluation of the proposal by comparing our system technology performance with other alternatives built on different technologies (Wi-Fi, Bluetooth, IrDA, ultrasound, etc.). We have also performed a location awareness proof concept test to analyze the viability of the approach.
Poly(ethylene oxide) (PEO) is the gold standard matrix for polymer electrolytes used in actual all-solid lithium batteries. However, PEO solid polymer electrolytes show some limitations; such as relatively low ionic conductivity and lithium transference number resulting in the actual polymer-lithium batteries operating at 70 °C. In the last years, polycarbonates (PC) have been presented as an alternative polymer matrix with superior ionic conductivity for solid batteries which may work at room temperature. In this article we systematically investigated the properties of new polymers which combine varying composition of both ethylene oxide and carbonate groups. A series of poly(ethylene oxide carbonates) (PEO-PCs) have been synthesized by polycondensation between different ethylene oxide diols and dimethyl carbonate. As a result, eight new PEO-PCs with number of ethylene oxide units ranging from 2 to 45 between carbonate groups were synthesized and characterized in terms of physico-chemical properties (Tm and Tg). These PEO2-45-PC were formulated as solid polymer electrolytes (SPE) by adding different amounts of bis(trifluoromethane)sulfonimide lithium salt. The effect of the SPE composition (ethylene oxide/carbonate ratio, salt content) on the ionic conductivity and thermal properties (glass transition temperature and melting temperature) was investigated. The optimum SPEs showing the lowest glass transition temperature led to highest ionic conductivity value of 3.7·10−5 S cm−1 at room temperature. FTIR spectra revealed the coordination between the carbonate groups in the polymer chain and the lithium salt. 7Li-19F NMR analysis T1 relaxation and diffusion coefficients measurements indicated local dynamics that correlates with the general conductivity behaviour.
The high efficient antireflective down-conversion Y2O3:Bi, Yb films have been prepared successfully on Si(100) substrates by pulsed laser deposition (PLD) method, Upon excitation of ultraviolet photon varying from 300 to 400 nm, near-infrared emission of Yb3+ was observed for the film, can be efficiently absorbed by silicon (Si) solar cell. Most interestingly, there is a very low average reflectivity 1.46% for the incident light from 300 to 1100 nm. To the best of our knowledge, this is the lowest reflectance for the down-conversion thin films prepared by cost efficient method. The surface topography of the high efficient antireflective films can be controllably tuned through the substrate template regulation by optimizing process parameters. Besides, the results showed that there is a close relationship between luminescent property and morphology of the film. With the change of the surface morphology, the intensity of Bi3+ and Yb3+ emission peaks increase first and then decrease. The obtained results demonstrate that this film can enhance the Si solar cell efficiency through light trapping and spectrum shifting.
Thermochemical heat storage is a promising technology towards efficient use of renewable energy resources. Materials based on salts and their hydrates have a high potential for a good energy storage density and the benefit of long-term storage ability. However, the process has not yet been successfully implemented due to limitations in mass and heat transfer. This paper investigates how to improve the less desirable properties of CaCl2 and its hydrates such as low melting points, agglomeration, low cycle stability and low sorption rates. The optimization of CaCl2 properties was achieved by mixing with KCl and impregnation in carrier materials to obtain a composite material. The tests show at first that, with the admixtures of KCl, water uptake during hydration is 2 times higher than that of CaCl2. Water release during dehydration is 1.3 times higher than that of CaCl2. Secondly, the use of compacted expanded natural graphite (ENG) or activated carbon foam (ACF) increases the cycle stability, thermal conductivity and the water sorption performance. Due to their hydrophobic nature those matrices have no influence on the reaction scheme, thus the total amount of water molecules sorbed by the salt-in-matrix is close to the value of CaCl2. The degree of impregnation varies from 31to90wt% depending on the host matrix and the impregnating medium used. The water vapour uptake is up to 0.61gg−1 and the water released ranges from 0.12 to 0.72gg−1. The thermal conductivity of CaCl2-in-matrixis is 3 times higher than that of sole CaCl2.
Identification of synthetic agonists and antagonists at orphan receptors represents an important step for understanding their physiological function and therapeutic potential. Accordingly, we have recently described a non-peptide agonist at the opioid receptor like (ORL1) receptor (1S,3aS)-8-(2,3,3a,4,5,6-hexahydro-1H-phenalen-1-yl)-1-phenyl-1,3,8-triazaspiro[4.5]decan-4-one (Ro64-6198; Jenck et al., PNAS 94 (2000) 4938; Wichmann et al., Eur. J. Med. Chem. 35 (2000) 839). We have investigated the effects of this compound in various tests of rodent neurological function, utilising ORL1 knockout mice to examine the pharmacological specificity of Ro64-6198. In male C57BL/6J mice, effects on balance and motor co-ordination were detected following low doses (0.3–1mg/kg IP) of Ro64-6198. At higher doses (1–3mg/kg IP), effects on swim behaviour and hypothermia was observed. At 10mg/kg, each effect became more profound and a severe neurological disturbance appeared, including loss of righting reflex. These effects of Ro64-6198 (10mg/kg IP) were absent in ORL1 receptor knockout mice. In male, hooded Lister rats, Ro64-6198 (6–10mg/kg IP), produced some disturbance of neurological function, including hypoactivity, rotarod performance, grip strength and mild hypothermia. An impairment of food responding under a variable interval (VI) 20s schedule of reinforcement was noted at 3mg/kg. These results confirm Ro64-6198 to be a highly selective pharmacological tool to investigate ORL1 receptor function in vivo and, furthermore, that activation of this receptor is accompanied by a variety of effects on neurological function.
Cobalt (oxy)-hydroxide (CoOOH) has recently been identified as a realistic active species under operando conditions for the electrocatalytic oxygen evolution reaction (OER), which plays a pivotal role in multiple energy conversion technologies. Therefore, searching for a high-yield method to fabricate advanced nanostructures and understanding their reactivity are challenging but urgent tasks. Here, rather than conventional liquid exfoliation, we report an electrochemical route for potentially large-scale production of ultrathin CoOOH nanosheets, which deliver exceptionally high OER activity. This “nearly-all-surface” material provides an excellent platform to study the surface chemistry for electrocatalytic activity. Combining operando X-ray spectroscopy and theoretical calculations demonstrated a potential-dependent deprotonation reaction, i.e., Co3+OOH is transformed into an active Co3+/4+OOH1−x phase for water oxidation under the applied potential. Comprehensive analysis suggested that reducing the deprotonation energy is the key to enhance the OER activity, and oxidized oxygen ions might act as electrophilic centers for the OER.
We report the preparation of copper sulphide nanoparticles from copper(II) piperidine dithiocarbamate. Powder XRD patterns confirmed covellite copper sulphide (CuS) for nanoparticles obtained at 120 °C while nanoparticles prepared at 180 and 220 °C exist in digenite copper sulphide (Cu9S5) crystalline phases. TEM micrographs showed CuS obtained at 120 °C have mixture of hexagonal, triangular, and spherical shapes with no agglomeration with crystallite sizes in the range 4.9–51.4 nm. Copper sulphide obtained at 180 °C have particle sizes in the range 31.3–44.0 nm while agglomerated particles were obtained at 220 °C with particle sizes of 74.4–125.4 nm. The results confirmed that the particle sizes of the as-prepared copper sulphide nanoparticles are temperature dependent. Optical studies of the copper sulphide nanoparticles indicates the absorption band edges are blue shifted due to decreased crystallite sizes of the nanoparticles compared to bulk copper sulphide.
This works reports the effect of operation conditions on the performance of a 25 cm2 vanadium redox flow cell (VRFC) featuring commercial carbon felt (CF) as electrode and different commercial membranes, namely electrolyte flow rate and charge-discharge current density. The effect of electrode compression and thermal treatment was also assessed. The battery performance was evaluated based on the charge-discharge curves and average efficiencies during 20 charge-discharge cycles; the capacity fading was evaluated after 20 cycles. The limiting current was obtained through polarization curves and the ohmic resistance of the battery was obtained by electrochemical impedance spectroscopy (EIS). The electrodes yielding the highest energy efficiency (EE), ca. 85%, at 40 mA cm−2 current density were thermally treated at 390 °C or 415 °C during 12 h under air. This result represents an improvement of more than 50% compared with the as-received electrodes. Additionally, energy efficiency increased ca. 10% when electrode compression rose from 8% to 25%. Increasing the flow rate from 37.5 cm3 min−1 to 150 cm3 min−1 EE was also enhanced from 76% to 84% at 40 mA cm−2. The type of membrane affects the performance: a comparison between a commercial anion exchange membrane (AEM) and Nafion® series cation exchange membranes (CEM) showed that AEM, generally, yields higher EE than all Nafion® membranes tested; however, the capacity fading of AEM is much higher than CEM. The information provided in this work shows that, by tuning operational conditions and using suitable components, it is possible to increase the performance of a VRFC without additional costs.
In the mainframe of a research contract, a feasibility pre-design study of a hydrogen-fuelled Laboratory-Village has been carried out: the goals are the design and the simulation of a demonstration plant based on hydrogen as primary fuel. The hydrogen is produced by electrolysis, from electric power produced by a mix of hydroelectric and solar photovoltaic plants. The plant will be located in a small remote village in Valle d’Aosta (Italy). This country has large water availability from glaciers and mountains, so electricity production from fluent water hydroelectric plants is abundant and cheap. Therefore, the production of hydrogen during the night (instead of selling the electricity to the grid at very low prices) could become a good economic choice, and hydrogen could be a competitive local fuel in term of costs, if compared to oil or gas. The H2 will be produced and stored, and used to feed a hydrogen vehicle and for thermal purposes (heating requirement of three buildings), allowing a real field test (Village-Laboratory). Due to the high level of pressure requested for H2 storage on-board in the vehicle, the choice has been the experimental test of a prototype laboratory-scale high-pressure PEM electrolyzer: a test laboratory has been designed, to investigate the energy savings related to this technology. In the paper, the description of the dynamic simulation of the plant (developed with TRNSYS) together with a detailed design and an economic analysis (proving the technical and economical feasibility of the installation) has been carried out. Moreover, the design of the high-pressure PEM electrolyzer is described.
An electrochemical supercapacitor in all solid configuration using perfluorosulfonate ionomer as polymer electrolyte has been successfully realized. Electrodes of supercapacitor have been prepared using activated carbon material and Nafion ionomer. This latter had the double function of binder and electrolyte. Nafion 115 membrane has been used as electrolyte separator in the preparation of small scale supercapacitors. The capacitance performance of these devices is comparable or better than traditional systems, which use sulfuric acid as electrolyte. The electrochemical evaluation of studied supercapacitor has been carried out by cyclic voltammetry, dc charge/discharge measurements and electrochemical impedance spectroscopy. A capacitance of 90F/g (referred to the weight of active carbon material in the electrode) has been obtained with carbon having surface area (SA) of about 1000m2/g and, a capacitance of 130F/g with activated carbon having SA of 1500m2/g. These interesting results have been tentatively explained with an optimal configuration of electrodes and with the concomitant beneficial effects on the carbon pores of adsorbed water and Nafion distribution, which produce low distribute resistance in the carbon composite electrodes.
Unique hierarchically porous carbon microcubes (CMCs) consists of irregular bubbles derived from metal organic frameworks (MOFs) have been prepared via simple hydrothermal synthesis method and carbonization treatment. Selenium nanoparticles are uniformly dispersed in the hierarchical porous structure of CMCs by a typical melt-diffusion process, and the yielding Se/CMCs composite is enabled as a cathode material for lithium-selenium rechargeable batteries. In the carbonate-based electrolyte, with Se loading of nearly ∼50 wt%, the Se/CMCs composite exhibits an ultrahigh initial discharge specific capacity of 780.4 mAh g−1 and still retains a reversible capacity of 425.2 mAh g−1 after 100 cycles at 0.2 C. Specially, these hollow structure CMCs with high conductivity contribute to the outstanding electrochemical properties by effectively decreasing the charge transfer resistance and suppressing polyselenides dissolution in carbonate electrolyte.
The effects of dopant on the electrochemical properties of spinel-type Li3.95M0.15Ti4.9O12 (M=Al, Ga, Co) and Li3.9Mg0.1Al0.15Ti4.85O12 were systematically investigated. Charge–discharge cycling were performed at a constant current density of 0.15mAcm−2 between the cut-off voltages of 2.3 and 0.5V, the experimental results showed that Al3+ dopant greatly improved the reversible capacity and cycling stability over the pristine Li4Ti5O12. The substitution of the Ga3+ slightly increased the capacity of the Li4Ti5O12, but did not essentially alleviate the degradation of cycling stability. Dopants such as Co3+ and Mg2+ to some extent worsened the electrochemical performance of the Li4Ti5O12.
Large swaths of the public lack a basic understanding of energy issues. This fact, coupled with a desire for a miracle that will mitigate energy and environmental concerns, makes clean energy an area ripe for hype. Many technologies are described that are possible, yet will never be practical. As scientists and engineers we must do better job explaining the difference. Practical limitations were ignored as the development of cellulosic ethanol rode a wave of optimism and hype earlier in this decade. It is now clear that cellulosic ethanol is not delivering on the promises made. Scientists and engineers will continue to show us what is possible. We must focus our efforts in energy on those technologies that can also be practical.
Surface engineering is highly desirable but still challenging for developing high-rate and long-term life energy storage materials. Herein, Prussian blue@polyaniline nanocube is synthesized by an aqueous precipitation method and the following polymerization process of aniline. Benefiting from the coordinating role of polyvinyl pyrrolidone between Prussian blue and polyaniline, Prussian blue@polyaniline nanocube presents a core-shell structure with a diameter of about 600 nm and the uniform polyaniline coating layer is averagely 20 nm in thickness. The incorporation of polyaniline on Prussian blue is efficient to enhance the electrical conductivity and the kinetics of Na+ transmission during cycling, leading to the higher specific capacity and better rate performance. The sodium storage properties of the cathode are also investigated in different voltage ranges. Owing to the core-shell structure and the optimized voltage range, Prussian blue@polyaniline electrode delivers a specific capacity of 108.3 mAh g−1 at 100 mA g−1 with a capacity retention of 93.4% after 500 cycles and maintains a considerable specific capacity of 90.3 mAh g−1 even at 2 A g−1 in the voltage range of 2.0–3.6 V. The strategy of polyvinyl pyrrolidone assisted polymerization of polyaniline layer on Prussian blue nanoparticles can be extended to surface modification for other electrode materials.