batterydata/paper-abstracts huggingface dataset:
Lithium metal electrode is pretreated with 1,3-dioxolane or 1,4-dioxane to improve its properties. The components and morphology of the surface films formed in the above two pretreatment liquids are studied using FTIR and SEM respectively. Li–LiCoO2 coin cells are then fabricated and their cycle and discharge performance are tested. It is found that the battery performance is greatly improved by such pretreatment. Interestingly, the 1,4-dioxane pretreatment is more effective than 1,3-dioxolane in improving the lithium metal electrode performance. To explore the mechanism(s) behind, the electrochemical impedance spectroscopy (EIS) is employed and an equivalent circuit model is designed for EIS analysis. The fitting curves are aligned well with the experimental curves, suggesting that the proposed equivalent circuit model is an ideal model for lithium battery. Next, the corresponding relationship between the impedance components and every individual semicircle in the Nyquist curves is inferred theoretically and the result is satisfying. Based on the analysis using this model, we conclude that the structural stability of SEI film is increased and the interfacial compatibility between the lithium substrate and the SEI film is improved by 1,3-dioxolane or 1,4-dioxane pretreatment.
The Hawaiian Electric Company intends to procure grid-scale Battery Energy Storage System (“BESS”) capacity. The purpose of this study is to determine whether providing contingency reserve or time-of-day shifting is of more benefit to the Oahu grid, and to better understand the relationship between BESS size and level of benefit. This is an independent study by Sandia, and is not being used to support the regulatory case for BESS capacity by Hawaiian Electric. The study team created a production cost model of the Oahu grid using data primarily from the Hawaiian Electric Company. The proposed BESS supplied contingency reserve in one set of runs and time-of-day shifting in another. Supplying contingency reserve led to larger savings than time-of-day energy shifting. Assuming a renewable reserve and a quick-start reserve, and $15/MMBtu for Low-Sulphur Fuel Oil, the 50-MW/25-MWh, 100-MW/50-MWh, and 150-MW/75-MWh systems supplying contingency reserve provided, respectively, savings of 9.6, 15.6, and 18.3 million USD over system year 2018. Over the range of fuel prices tested, these cost savings were found to be directly proportional to the cost of fuel. As the focus is the operational benefit of BESS capacity, the capacity value of the BESS was not included in benefit calculations.
Objective To determine factors that contribute to living well with aphasia in the first 12 months poststroke. Design Prospective longitudinal cohort study. Setting Hospitalized care, ambulatory care, and general community. Participants A referred sample of people (N=58) with a first incidence of aphasia after stroke was assessed at 3, 6, 9, and 12 months postonset. Participants were recruited through speech-language pathologists in 2 capital cities in Australia. Presence of aphasia was determined through the Western Aphasia Battery-Revised by an experienced speech-language pathologist. Interventions Not applicable. Main Outcome Measures The main outcomes were the 5 domains of the Assessment for Living with Aphasia at 3, 6, 9, and 12 months poststroke. The independent variables included demographics, physical functioning, social network, mood, aphasia severity, and a self-rating of successfully living with aphasia at the same time points. Mixed effects modeling was used to determine which factors contributed to the trajectory of each of the 5 domains of participation, impairment, environment, personal factors, and life with aphasia. Results Higher household income, larger social network size, being a woman, and having milder aphasia were positively associated with the participation domain. Graduate or postgraduate educational levels, low mood, and poor physical functioning were negatively associated with the participation domain. Factors positively associated with other domains included higher income, self-ratings of successfully living with aphasia, and aphasia severity. Low mood was consistently negatively associated with all of the domains. Conclusions Psychosocial determinants were the most significant predictors of living well with aphasia in the first 12 months postonset. Aphasia rehabilitation needs to attend more to these factors to optimize outcomes.
We investigated whether the morphology of microglia in the molecular layer of the dentate gyrus (DG-Mol) or in the lacunosum molecular layer of CA1 (CA1-LMol) was correlated with spatial learning and memory in the capuchin monkey (Cebus apella). Learning and memory was tested in 4 monkeys with visuo-spatial, paired associated learning (PAL) tasks from the Cambridge battery of neuropsychological tests. After testing, monkeys were sacrificed, and hippocampi were sectioned. We specifically immunolabeled microglia with an antibody against the adapter binding, ionized calcium protein. Microglia were selected from the middle and outer thirds of the DG-Mol (n =268) and the CA1-LMol (n =185) for three-dimensional reconstructions created with Neurolucida and Neuroexplorer software. Cluster and discriminant analyses, based on microglial morphometric parameters, identified two major morphological microglia phenotypes (types I and II) found in both the CA1-LMol and DG-Mol of all individuals. Compared to type II, type I microglia were significantly smaller, thinner, more tortuous and ramified, and less complex (lower fractal dimensions). PAL performance was both linearly and non-linearly correlated with type I microglial morphological features from the rostral and caudal DG-Mol, but not with microglia from the CA1-LMol. These differences in microglial morphology and correlations with PAL performance were consistent with previous proposals of hippocampal regional contributions for spatial learning and memory. Our results suggested that at least two morphological microglial phenotypes provided distinct physiological roles to learning-associated activity in the rostral and caudal DG-Mol of the monkey brain.
High penetration of renewable energy poses a significant challenge in operation of power system. A potential solution for this problem is utilizing Battery Energy Storage System (BESS). The purpose of this paper is to analyze the effectiveness of BESS ability to peak shave and smooth the load curve of an actual circuit on the island of Maui in Hawaii. The distribution circuit has about 850 kW of installed rooftop Photo-Voltaic (PV) generation. Higher penetration of PV increases the concern about the potential impacts on the transmission system. At first, we will present two different methods for load forecasting. Reliable forecasting of daily load is required to effectively utilize the BESS system. We have employed two different methods for load forecasting in order to achieve two main purposes including peak shaving and smoothing. For reaching these goals, two approaches are analyzed. The first approach is utilizing a nonlinear programming method in terms of load shifting and smoothing. The second approach includes a real time control strategy to have smoothing and peak shaving at the same time. As a real case study, these proposed methods have been applied within 108-day data collection period and pros and cons of these methods will be discussed.
A comparative study of ex-situ and operando X-ray diffraction techniques using the fast lithium ion conductor Li0.18Sr0.66Ti0.5Nb0.5O3 is presented. Ex-situ analysis of synchrotron X-ray diffraction data suggests that a single phase material exists for all discharges to as low as 0.422 V. For samples discharged to 1 V or lower, i.e. with higher lithium content, it is possible to determine the lithium position from the X-ray data. However, operando X-ray diffraction from a coin cell reveals that a kinetically driven two phase region occurs during battery cycling below 1 V. Through monitoring the change in unit cell dimension during electrochemical cycling the dynamics of lithium insertion are explored. A reduction in the rate of unit cell expansion of 22(2)% part way through the first discharge and 13(1)% during the second discharge is observed. This reduction may be caused by a drop in lithium diffusion into the bulk material for higher lithium contents. A more significant change is a jump in the unit cell expansion by 60(2)% once the lithium content exceeds one lithium ion per vacant site. It is suggested that this jump is caused by damping of octahedral rotations, thus establishing a link between lithium content and octahedral rotations.
Solid oxide fuel cells (SOFCs) offer great promise for the most efficient and cost-effective conversion to electricity of a wide variety of fuels such as hydrocarbons, coal gas, and gasified carbonaceous solids. However, the conventional Ni-YSZ (yttria-stabilized zirconia) anode is highly susceptible to deactivation (poisoning) by contaminants commonly encountered in readily available fuels, especially sulfur-containing compounds. Thus, one of the critical challenges facing the realization of fuel-flexible and cost-effective SOFC systems is the development of sulfur-tolerant anode materials. This perspective article aims at providing a comprehensive review of materials that have been studied as anodes for SOFCs, the electrochemical behavior of various anode materials in H2S-contaminated fuels, experimental methods for ex situ and in situ characterizations of species and phases formed on anode surfaces upon exposure to H2S-containing fuels, mechanisms for the interactions between H2S and anode surfaces as predicted from density functional theory (DFT) calculations, and possible strategies of minimizing or eliminating the effect of sulfur poisoning. While significant progress has been made in developing alternative anode materials with better sulfur tolerance, in probing and mapping electrode surface species relevant to sulfur poisoning, and in unraveling the mechanisms of H2S–anode interactions using both computational and experimental approaches, many challenges still remain to bridge the gaps between models at different scales or between theoretical predictions and experimental observations. An important new direction for future research is to develop a predictive multi-scale (from DFT to continuum) computational framework, through a rigorous validation at each scale by carefully-designed experiments performed under in situ conditions, for rational design of better sulfur-tolerant anode materials and structures for a new generation of SOFCs to be powered by readily available fuels.
Abstract The highly attractive properties of polymer–clay nanocomposite (PCNs), such as high dimensional stability, heat deflection temperature, gas barrier performance, reduced gas permeability, optical clarity, flame retardancy, recommend for several different applications such as food packing, biomedical applications, wastewater pretreatment, electricals/electronics, optoelectronics, sensors, and automobiles. This chapter presents a review of the recent advances in PCNs research study including their different industrial and technological applications. We will not attempt to cover in detail all of these PCNs and their applications but will explain the main applications of them as a whole with their numerous practical examples. The different techniques used to prepare PCNs and their characterizations are also reviewed.
The practical applications of high capacity metallic Li electrodes is severely hindered by the uncontrollable Li nucleation and growth that lead to poor cycle life and growth of unsafe dendrites. Here we demonstrate the design of porous but robust sponges with Cu nanoparticles and graphene and their applications for enabling Li electrodes with stable cycling under high capacity and high current conditions. We discovered that the Cu nanoparticles decorated on graphene effectively direct the heterogeneous nucleation of Li whereas the graphene frameworks provide ample spaces for confining Li growth. These sponges are able to host at least 60 mAh cm−2 Li without forming dendrites and allow stable Li plating/stripping with low overpotentials for hundreds of cycles even at a high current of 7 mA cm−2. The sponges have remarkable mechanical strengths and exhibited minimal structural deformation after aggressive plating/stripping cycles. These superior properties enable Li metal batteries with substantially improved high current cyclic stability and rate performance, as demonstrated with both LiNi0.4Co0.2Mn0.4O2 and LiFePO4 cathodes.
The electrochemical properties of 2,5-dimercapto-1,3,4-thiadiazole (DMcT)–polyaniline (PAn) composite films containing Ag nanoparticles (Ag-NPs; Ø 17nm) were investigated. Adding the nanoparticles to DMcT–PAn composites, charge–discharge performance of the composite was enhanced due to electrocatalytic activation of DMcT by the nanoparticles. Optimum content of the Ag-NPs was 5wt.%. The observed current enhancement was ascribed to the improve efficiency of DMcT utilization in the composites due to electrocatalytic activation of the DMcT redox reactions in the presence of Ag-NPs.
In this work, we investigated the anodic stability and decomposition mechanism of sulfolane (SL). The anodic stability of SL-based electrolyte with different lithium salts on Pt and LiNi0.5Mn1.5O4 electrodes was found to decrease as follows: LiPF6/SL>LiBF4/SL>LiClO4/SL. The oxidation potential of 1M LiPF6/SL electrolyte on both Pt and electrodes is about 5.0V vs Li/Li+. The presence of PF6 - and another SL solvent dramatically alters the decomposition mechanism of SL. Oxidation decomposition of SL-SL cluster is the most favorable reaction in LiPF6/SL electrolyte. The dimer products with S-O-R group were detected by IR spectra on the charged LiNi0.5Mn1.5O4 electrode surface and in the electrolyte near the electrode surface, and were found to increase the interfacial reaction resistance of the LiNi0.5Mn1.5O4 electrode.
Li2MSiO4 (M – transition metal) is a promising class of materials for lithium-ion batteries due to the possibility of reversible extraction of two lithium ions per formula unit (theoretical capacity 333 mAh g−1). Here, we report a combined approach of synthesizing Li2FeSiO4 (LFS) by polyol method and doping multi-walled carbon nanotubes (MWCNTs) to create an inter-particle conductive network. The prepared Li2FeSiO4 is of orthorhombic phase (space group Pmn21), with no substantial change on adding MWCNTs. An average particle size of 120 nm and the presence of an inter-particle conducting network are observed in the LFS-CNT sample. Electrochemical performance of the LFS materials was evaluated by assembling CR2032 coin cells with Li anode and 0.2 m BMPyTFSI-LiTFSI ionic liquid electrolyte at room temperature. Pure LFS delivered a discharge capacity of 165 mAh g−1 while LFS-CNT delivered 270 mAh g−1 at C/20 rate. LFS-CNT has a superior rate capability and a lower charge-transfer resistance (RCT = 10 Ω) than pure LFS (RCT = 53 Ω). The MWCNTs also serve as active lithium sites, significantly improving the Li+ diffusion kinetics during cycling. Our results demonstrate that the polyol method enables particle size-reduction, and facilitates in-situ carbon-coating of individual particles to improve their electronic conduction.
This study applied two in operando techniques to reveal the reaction kinetics of solid electrolyte interphase formation on electrolyte and benzimidazole salt additives. The results obtained from studying interface effects reveal changes in solid electrolyte interphase mass, reflection angle, and reflection intensity within the electrolyte additives in accordance with electron-withdrawing and electron-donating substitutions. Surface plasma resonance results reveal that the electrolyte containing the electron-withdrawing salt additive exhibited the highest rate constant (774 s−1) of the binding reaction between the benzimidazole additive and Au surface, indicating the strong reaction effects on Au. The electrolyte containing the electron-withdrawing salt additive accelerates and facilitates the dissociation reaction of the ethylene carbonate–lithium ion (EC–Li+) ionic cluster. From the quartz crystal microbalance results, the electrolyte containing the electron-withdrawing salt additive shows the greatest solid electrolyte interphase mass (14.84 μg cm−2), representing the intense dissociation reactions of the EC–Li+ ionic cluster as well as solid electrolyte interphase formation and recombination. In this study, selecting a high rate constant and high binding strength of the EC–Li+ ionic cluster on the electrode surface enhance solid electrolyte interphase formation and battery performance.
Ultrafine core-shell NiO@SiO2 nanopowders with various shell thicknesses were prepared by one-pot flame spray pyrolysis. The mean diameters of the NiO nanoparticles with 0, 2, and 5 wt% SiO2 were 13, 10, and 9nm, respectively. The coating of the NiO nanopowders with amorphous SiO2 was confirmed by transmission electron microscopy, zeta potential analysis, and X-ray photoelectron spectroscopy. The initial discharge capacities of the NiO nanopowders with 0, 2, and 5 wt% SiO2 at a current density of 1Ag−1 were 1123, 1165, and 1145mAhg−1, with corresponding initial Coulombic efficiencies of 66, 63, and 69%, respectively. The discharge capacities of the NiO nanopowders with 0, 2, and 5 wt% SiO2 after 150 cycles were 440, 669, and 554mAhg−1, with capacity retentions from the second cycle of 58, 74, and 68%, respectively. The structural stability of the core-shell NiO@SiO2 nanoparticles during repeated Li charging and discharging improved the cycling and rate performances of the electrodes as compared with those containing bare NiO nanopowders.
Instrumentation and techniques utilized for both field and site inspections, as well as for laboratory examinations, are discussed. Key background information to be gathered during a site visit is reviewed. This chapter also discusses the features on a plastic part that allow for generic identification of the material, material manufacturer, processing, and relevant standards to which the product was manufactured. The use of photography and microscopy for obtaining detailed fracture information is also reviewed. The relevance of specific fracture related features such as crack opening displacement, crack branching, discoloration, and gross deformation is also discussed in the context of understanding the failure process(es). Various test methods available for laboratory testing of specific material properties, along with their application to failure analysis, are listed.
Thin and mechanically stable proton-exchange membranes with high V(IV) barrier properties and good proton conductivity have been fabricated by polymer blending of sulfonated poly(ether ether ketone) with polyaniline. V(IV) diffusion coefficient of blended membranes in a wt. ratio of 80/20 was 2.6 and 6 times lower than for pure sulfonated poly(ether ether ketone) and Nafion 112 membrane, respectively. This behaviour is assumed to be caused by a densified polymer matrix given by acid/base interactions between the two polymers. Blended membranes in a wt. ratio of 80/20 had a good proton conductivity of 54.15mScm−1 and ion exchange capacity of 1.44mmolg−1. The membranes were also characterized in all-vanadium redox flow battery, where only slightly higher efficiencies were achieved than for pure polymer. Slow PANI degradation determines a decrease in membrane performance, reaching values close to the starting polymer (SPEEK-E600). Therefore, the application of blended membranes in the all-vanadium redox flow battery is not advantageous. However, the improved barrier properties are likely to be beneficial for their application in vanadium/air-redox flow battery in order to reduce oxygen crossover. In the latter, no V(V) ions can oxidize the blend polymer.
The electrochemical synthesis of titanium dioxide nanotubes (TNTs) on titanium alloys depends on the electrolyte composition and process parameters. To gain insight of titanium oxidation on commercially pure titanium grade 2 (cpTi-2), the effects of individual electrolyte species have been investigated by cyclic voltammetry. At constant 60 V potential, different nanotubular structures were obtained by varying time. Under synergistic action of anionic species and electric field with increase in anodizing time, the field enhanced dissolution become dominant as validated from the increase in the inner tubes diameter and decrease in wall thickness. On the other hand, the dissolution of inter-tubular region was also observed which resulted in the separation of nanotubes at higher anodizing time. The electrochemical performance of anodized samples has been evaluated in 1 wt% NaCl. The lower corrosion current density and passive current density registered by 30 min anodized sample corresponded to the limited ingress of ionic species at the Ti/TNTs interface compared to 60, 90, 120 and 150 min samples which contained large inter-tubular spacing. The electrochemical impedance spectroscopy (EIS) analysis was in support to potentiodynamic results confirming the diffusion-controlled reactions at the Ti/TNTs interface.
Chemical lithiation with LiI in acetonitrile was performed for amorphous FePO4 synthesized from an equimolar aqueous suspension of iron powder and an aqueous solution of P2O5. An orthorhombic LiFePO4 olivine structure was obtained by annealing a chemically lithiated sample at 550°C for 5h in Ar atmosphere. The average particle size remained at approximately 250nm even after annealing. The lithium content in the sample was quantitatively confirmed by Li atomic absorption analysis and 57Fe Mössbauer spectroscopy. While an amorphous FePO4/carbon composite cathode has a monotonously decreasing charge–discharge profile with a reversible capacity of more than 140mAhg−1, the crystallized LiFePO4/carbon composite shows a 3.4V plateau corresponding to a two-phase reaction. This means that the lithium in the chemically lithiated sample is electrochemically active. Both amorphous FePO4 and the chemically lithiated and annealed crystalline LiFePO4 cathode materials showed good cyclability (more than 140mAhg−1 at the 40th cycle) and good discharge rate capability (more than 100mAhg−1 at 5.0mAcm−2). In addition, the fast-charge performance was found to be comparable to that with LiCoO2.
By an oxidative-coupling copolymerization with coumarin, the oxidation potential of polytriphenylamine was improved to 3.75V from 3.60V. The copolymer exhibited excellent electrochemical activity in redox cycling. The separator used in the experiment was prepared by roll pressing the copolymer powder with 30% (wt.) polytetrafluoroethylene into a ∼80μm thick sheet, which was incorporated into a LiFePO4–Li cell. Tests showed that when the cell was overcharged to 3.789V, the copolymer separator was oxidized and became electronically conducting, which caused short circuit formation and prevented the organic electrolyte from being oxidized. Although the cell was overcharged at 0.3C for 5h, the voltage was stable at 3.789V. When discharged, the cell released all its capacity at normal charge. The cell was overcharged seven times with identical results obtained for each cycle. Overcharging at different rates demonstrated that the separator could exhibit reversible, self-activating protection for LiFePO4-based batteries, even at 1.3mA/cm2 (3.2C to the cell).