batterydata/paper-abstracts huggingface dataset:
Metal dissolution from the positive electrode and redeposition on the negative electrode is one of the well-known failure processes in lithium-ion batteries (LIBs). And it is necessary to take effective measures to prevent this kind of issue from happening. This study examines the Mn tolerance of electrolytes based upon lithium bis(oxalato)borate (LiBOB) and LiPF6. Results show that compared with LiPF6-based cell, the one based on LiBOB is impacted less by dissolved Mn2+ ions. When Mn concentration in electrolyte is less than 50ppm, the adverse effect of additive Mn2+ ions is tolerable, due to the excellent film-forming properties of LiBOB itself. However, when Mn concentration in LiBOB-based electrolyte is higher than 50ppm, a small amount of Mn ions are detected on the graphite electrode. Subsequently, continuous decomposition products of the electrolyte induced by the deposited Mn compounds may hinder the intercalation of lithium into the graphite, thereby reducing the reversibility of the lithium intercalation. This study suggests that LiBOB-based electrolyte is an alternative electrolyte for relatively low-cost manganese-based electrodes by improving Mn tolerance to some extent.
The aim of this work was to compare the electrochemical behaviors and safety performance of graphite and the lithium titanate spinel Li1.33Ti1.67O4 with half-cells versus Li metal. Their electrochemical properties in 1M LiPF6/EC+DEC (1:1 w/w) or 1M LiPF6/PC+DEC (1:1 w/w) at room and elevated temperatures (30 and 60°C) have been studied using galvanostatic cycling. At 30°C graphite has higher reversible capacity than Li1.33Ti1.67O4 when using the LiPF6/EC+DEC as electrolyte. At 60°C graphite declines in cell capacity yet Li1.33Ti1.67O4 remains almost unchanged. In a propylene carbonate (PC) containing electrolyte, graphite electrode exfoliates and loses its mechanical integrity while Li1.33Ti1.67O4 electrode is very stable. An accelerating rate calorimeter (ARC) and microcalorimeter have been used to compare the thermal stability of lithiated lithium titanate spinel and graphite. Results show that Li1.33Ti1.67O4 may be used as an alternative anode material offering good battery performance and higher safety.
Several series of Li1±x Mn2−y O4±δ and Li1.05Al y Mn1.95−y O4±δ samples with different oxygen defect degree have been synthesized by controlling synthesis temperature and procedures. The cycle performance of spinel as cathode in lithium batteries has been correlated with oxygen deficiency. The structure change of spinel during charge has also been investigated with respect with oxygen deficiency.
A simple one-step and low-temperature synthesis approach has been developed to grow hierarchical NiCo2S4 ultrathin nanosheets (2–3 nm in thickness) on Ni foam. Owing to the unique nanoarchitecture, the NiCo2S4 nanosheets not only offer abundant electro-active sites for energy storage, but also have good electrical and mechanical connections to the conductive Ni foam for enhancing reaction kinetics and improving electrode integrity. When used as anodes for Li-ion batteries, the NiCo2S4 nanosheets demonstrate exceptional energy storage performance in terms of high specific capacity, excellent rate capability, and good cycling stability. The mild-solution synthesis of NiCo2S4 nanostructures and the outstanding electrochemical performance enable the novel electrodes to hold great potential for high-efficient energy storage systems.
Three-dimensional free-standing nanoarray electrodes with hierarchical structure grown on carbon cloth substrate have attracted great interest for flexible energy storage devices. However, the direct growth of active material with a large mass loading on carbon fibers is difficult because of the hydrophobic nature. Herein, “two-step” growth route is adopted to achieve high-loading Ni-Co carbonate hydroxide nanowire arrays, in which the effect of electrochemical pre-activation is discussed. A facile and novel process is used to boost the areal capacity by converting Ni-Co carbonate hydroxide nanowires to hydroxide nanowire-supported nanoplate arrays in an alkaline solution. The areal capacity of the as-soaked free-standing Ni-Co hydroxide nanoarrays electrode increases from 856mC·cm−2 (152C·g−1) to 1944mC·cm−2 (348C·g−1) and 3028mC·cm−2 (542C·g−1) at 2mA·cm−2 after soaking for 8h and 16h. The electrochemical pre-activation is important for achieving high mass loading as well as high rate capability. Moreover, the as-soaked electrode is employed as the positive electrode for hybrid supercapacitor. The device possesses a high areal capacitance of 1.47F·cm−2 at 1mA·cm−2, a large energy density of 6.7mWh·cm−3 at 11.6mW·cm−3. This work gives an insight for designing high-loading three-dimensional electrodes and paves a new way to construct binder-free film electrode for high-performance hybrid supercapacitor applications.
Implementation of polymer electrolyte fuel cells (PEMFCs) for stationary power applications requires the demonstration of reliable fuel cell stack life. One of the most critical components in the stack and that most likely to ultimately dictate stack life is the membrane electrode assembly (MEA). This publication reports the results of a 26,300h single cell life test operated with a commercial MEA at conditions relevant to stationary fuel cell applications. In this experiment, the ultimate MEA life was dictated by failure of the membrane. In addition, the performance degradation rate of the cell was determined to be between 4 and 6μVh−1, at the operating current density of 800mAcm−2. AC impedance analysis and DC electrochemical tests (cyclic voltammetry and polarization curves) were performed as diagnostics during and on completion the test, to understand materials changes occurring during the test. Post mortem analyses of the fuel cell components were also performed.
Exploring advanced electrocatalysts with unprecedented catalytic efficiency for oxygen evolution reaction (OER) of water splitting is of great importance in many energy conversion and storage systems. Based on our previous findings that short H-bonding on reconstructed βII-Li2CoSiO4 (LCS) nanocrystal surface to enhance OER activity by facilitating proton transfer/dissociation and an electronic push/pull effect of Co and Fe doping on OER performance of Ni-based hydroxides, here we report both combination of Fe-Co synergistic effect with charge transfer and short H-bonding on Li2CoxFe1-xSiO4 (LCxF1-xS, 0 < x < 1) nanocatalyst surface can further enhance OER performances of water splitting. Especially, LiC0.5F0.5S exhibits superior OER activity and super-long term stability (no fade after 10,000 CV cycles, high temperature of 80 ℃, and 100 h OER measurement at a low overpotential of 0.3 V with high current density of 80 mA cm−2). Insight of the ultrahigh OER performance of LC0.5F0.5S is suggested to attribute to the short H-bonding formed on the constructed surface and the synergistic coupling effect between Fe and Co with charge transfer, which leads to favorable electronic structure of TM active sites, promotes proton out of the oxygen on Co site and generates H2O on Fe site by proton transfer.
Polymer electrolytes were prepared using 1 M LiPF6 in ethylene carbonate–dimethyl carbonate 1:1 wt/wt (LP 30 SelectiLyte™: LP 30 henceforth), N-n-butyl-N-methylpyrrolidinium hexafluorophosphate ([Py14]PF6), and poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP). To determine adequate composition of liquid electrolyte, we investigated the effect of the ratio of [Py14]PF6 to LP 30, in terms of thermal stability, ionic conductivity and electrochemical stability. The solution, LP 30 with 30 wt% [Py14]PF6, gave better properties compared to pure LP 30 and other mixtures examined in this study. Then this was used for galvanostatic charge–discharge tests of a lithium cell. The cell, with the chosen electrolyte solution, demonstrated reversible capacity reaching the theoretical values, when Li metal was combined with LiFePO4 or Li4Ti5O12 electrode. A polymer membrane was prepared by combining the chosen solution with PVdF-HFP matrix. The ionic conductivity of this membrane was 4 × 10−4 S cm−1 at room temperature. Furthermore, the polymer electrolyte displayed reasonable thermal stability, reflecting the properties of [Py14]PF6 in improving the performance of the polymer electrolyte.
Composites of monoclinic Li3−x M′ x V2−y M″2y (PO4)3 (M′=K, M″=Sc, Mg+Ti) with carbon were synthesized by solid-state reaction using oxalic acid or 6% H2/Ar gas mixture as reducing agents at sintering temperature of 850°C. The samples were characterized by X-ray diffraction (XRD), voltammetry and electrochemical galvanostatic cycling. The capacity of Li3V2(PO4)3 synthesized using hydrogen as the reducing agent was 127mAhg−1 and decreased to 120mAhg−1 after 20 charge–discharge cycles. The substitution of lithium and vanadium for other ions did not result in the improvement of the electrochemical characteristics of the samples.
Individuals with schizophrenia demonstrate impairment in prospective memory (ProM), which describes the multifaceted ability to execute a future intention. Despite its clear implications for everyday functioning, the neuropsychological substrates and functional correlates of ProM impairment in schizophrenia remain poorly understood. In this study, the Memory for Intentions Screening Test (MIST), a standardized measure of ProM, was administered to 72 outpatients with schizophrenia or schizoaffective disorder as part of a comprehensive neuropsychological and psychiatric research evaluation. Results showed that ProM was positively correlated with standard clinical tests of attention, working memory, processing speed, learning, and executive functioning, but not delayed recall. In the context of multiple neuropsychological predictors, learning ability was the only domain that independently contributed to ProM. Importantly, better ProM was predictive of higher functional capacity (as measured by the UCSD Performance-Based Skills Assessment-Brief Version), above and beyond the variability explained by demographic and disease factors. Analysis of component processes revealed that event-based ProM, as well as no response (i.e., omission) and task substitution errors were the strongest predictors of everyday functioning. Overall, these findings suggest that ProM impairment in schizophrenia is associated with multiple cognitive substrates, particularly episodic learning deficits, and plays an important role in everyday living skills. Studies regarding the potential effectiveness of ProM-based remediation strategies to improve functional outcomes in schizophrenia are indicated.
Introduction.– Les cérébrolésés peuvent présenter des troubles du langage hors aphasie ayant un impact communicationnel. Ils seraient le résultat d’une altération d’autres fonctions cognitives. Leur évaluation n’est pas toujours adaptée. Objectifs.– Nous proposons une nouvelle analyse des fluences, du Dice Game et du Hayling Test afin de souligner la particularité de ces troubles. Des études de cas illustreront ces déficits langagiers. Méthodes.– Nous proposons une normalisation de trois tests alliant langage et fonctions exécutives : Fluences, Hayling Test, Dice Game à une population contrôle de 18–25ans et de 40–60ans répartie en six groupes. Nous entamons un début de validation en comparant des patients cérébrolésés non aphasiques à la norme calculée. Pour les fluences, nous utilisons une nouvelle cotation, avec proposition d’une analyse qualitative, visant à objectiver les stratégies de recherche active en mémoire. Résultats.– Aux fluences, certains patients présentant des scores normaux en quantitatif montrent des particularités en qualitatif. Au Hayling Test, les erreurs sont plus nombreuses et plus variées que chez les sujets témoins, et l’on note une fatigabilité. Au Dice Game, les patients omettent souvent des propositions essentielles à la compréhension de l’interlocuteur. Par ailleurs, les tests exécutifs langagiers sont toujours altérés lorsque l’équivalent non verbal est déficitaire ; cependant la réciproque n’est pas vraie. Discussion.– La proposition d’une nouvelle cotation pour les fluences nous permet d’analyser plus précisément les productions des patients souffrant de troubles exécutifs, en envisageant non plus l’aspect quantitatif seul, mais aussi l’aspect qualitatif des productions. Ces trois tests s’avèrent donc sensibles et pertinents dans l’évaluation des troubles exécutifs chez les patients cérébrolésés non aphasiques. Conclusion.– Ces trois tests, d’une durée de passation assez courte, permettent ainsi d’approfondir l’évaluation des capacités de communication en proposant des tests plus fins que nos batteries de langage habituelles.
Molybdenum doped layered Li[Ni1/3+x Co1/3Mn1/3−2x Mo x ]O2 materials were synthesized by an ultrasonic spray pyrolysis method. A single phase of Li[Ni1/3+x Co1/3Mn1/3−2x Mo x ]O2 could be prepared in 0≤ x ≤0.05 region. Structural and electrochemical properties of the Li[Ni1/3+x Co1/3Mn1/3−2x Mo x ]O2 were characterized by X-ray diffraction, Rietveld refinements and galvanostatic charge/discharge tests. The discharge capacity increased with the molybdenum doped, x in 0.01 sample is exhibited a higher discharge capacity of 175mAhg−1 with a good capacity retention.
To enhance the low cycle stability of LiCoPO4, the development of stable separators in batteries is required, since they are oxidized in the high-voltage system at around 5 V, affecting the cycle performance of high-voltage lithium-ion batteries. The performance of the batteries also depends on the porous structure of separators. Here we report improved coulombic efficiency and capacity retention of LiCoPO4 by using a three-dimensionally ordered macroporous polyimide (3DOM PI) separator, compared with a conventional polypropylene separator with heterogeneous pore structure. The enhanced cycle stability of the cell using 3DOM PI separator is attributed to its ordered macroporous structure and high anodic stability. The uniform current distribution created by the ordered macroporous structure results in the low overpotential during charge process, preventing the oxidation of electrolyte and the growth of the resistive film on the cathode surface during cycling. Furthermore, the high anodic stability of 3DOM PI separator maintains its chemical and macroporous structures after cycling at high potentials, leading to the superior stability of the cell.
Brackish water are any water sources with TDS between 1000 and 15000mg/L. Brackish water cannot be consumed by us directly due to its high salinity. According to World Health Organization (WHO), water with salinity below 500mg/L is acceptable as drinking water. There are quite a large number of research that had been done on BWRO. Each of them has agreed with a common design on optimum BWRO design with a slight modification in order to improve more and make a better BWRO system. BWRO systems which have been tested in real situation agree that the single stage system with module connected to reject water is the most optimum system both economically and environmentally. There is some improvement done to the design by using SWRO membrane at the second stage. This improvement increases recovery rate to about 83% and reduces boron concentration at the same time. Another design is by using hybrid combination of ultra-low and conventional RO membranes. Hybrid improves permeate quality. It is also possible to create a hybrid array by mixing membrane element types within a pressure vessel itself. Co-operating an efficient module arrangement into a complete BWRO system will reduce energy consumption. Energy-recovery device is a component that must be included in any small or large-scale systems. A small-scale RO system, without energy recovery, would typically consume two to three times more energy. This will be more for large-scale systems. While single stage system with module connected to reject water is preferred by researchers who have done real environment testing, simulation prefers to add another membrane to the reject water of the second module. This system is yet to be tested in real environment to prove its standing.
Lithium-rich spinels were obtained with the same structure but different surface area by two different synthesis routes, namely the “once-annealed” and the “twice-annealed” methods. The elevated temperature performance of Li/Li1+x Mn2O4 cell is significantly improved using a spinel cathode with a small surface area: the cell at 50°C lost 5% of the initial capacity over the first 100 cycles based on a spinel cathode with the small surface area of 1.2 m2/g compared to 8% based on a large one of 6.2 m2/g. Also the mechanism responsible for the reaction of LiMn2O4 with LiOH to form lithium-rich spinel has been investigated.
In this paper we report on recent results from our group, namely on the interface ionic liquid/electrode, plasma electrochemistry and electrodeposition of selenium and of macroporous structures. Ionic liquids show an interesting and liquid dependent surface chemistry: in some liquids the long range “herringbone” superstructure of Au(111) is visible, in others it is not. Glow discharge plasmas can be employed as a contact free electrode to make nanoparticles in solutions, e.g. nanoparticles of germanium. Selenium can be electrodeposited from ionic liquids under environmental conditions in an open cell and both the red and the grey phases of selenium are feasible. With the help of self organized opal structures of polystyrene spheres macroporous materials of Ag, Al and conducting polymers can be made. The prospects and limits of ionic liquids in surface electrochemistry and electrodeposition are shortly discussed.
Although hard carbon is deemed to be the most potential industrialized sodium-ion batteries anode material, there are still some problems need to be solved. In this study, a waste biomass of reed straw is pretreated by using a new strategy-hydrothermal treatment instead of pickling and successfully transformed to hard carbon materials through subsequent carbonization process. The reed straw carbonized at 1300 °C exhibits an impressively high reversible capacity of 372.0 mAh g−1 with excellent initial coulombic efficiency of 77.03% and outstanding cycling stability. Significantly, the sodium storage mechanism in our electrodes is mainly summarized into two models. Moreover, we find the interlayer spacing of graphite-like nanocrystal of obtained hard carbon influences the sodium ion diffusion ability, thereby affecting the rate performance. Our work offers a simple and eco-friendly way for converting biomass to highly capacity carbon as well as a towardly anode material for sodium-ion batteries, which will open up new avenues of other biomass carbon materials with promising applications.
Anode materials with long cycling life and rate capability have remained a great challenge for sodium-ion batteries. Herein, a vanadium-based orthophosphate, NaV3(PO4)3/C nanocomposite has been investigated as a novel anode material for Na-ion batteries. The electrochemical performance of NaV3(PO4)3/C nanocomposite is evaluated in Na-half cell, which delivers a reversible capacity of 146mAhg−1 at the charging/discharging rate of 1C, and remarkable rate capability. EIS, XPS and in-situ XRD are performed to give the insight into interfacial property of electrode and structural evolution of material during cycling. The excellent cycling stability could be attributed to stable interface at higher cutoff voltage and slight change of structure with intercalation/deintercalation of Na+. Moreover, we achieve a Na-ion full battery with long term cycle life based on NaV3(PO4)3/C anode and Na3V2(PO4)3/C cathode, retaining 80% of initial capacity after 1000 cycles at charging/discharging rate of 5C, suggesting the feasibility of the as-obtained materials applied as a promising candidate for anode of Na-ion batteries.
Power systems with photovoltaic (PV) arrays combined with battery backup storage are becoming increasingly used because of their capability of working in power island mode, especially during grid outages. The problem is to decide the optimal battery sizes for PV + battery systems with given solar array sizes, from both power supply reliability and economical perspectives. An optimization method based on the simulation of system operation during grid interruption is developed to investigate the effects of battery size on system output reliability level of meeting load demand with minimum cost. Case studies are conducted for validation according to actual solar irradiation data, load profiles and realistic power interruption statistics. Sensitivity analysis is also performed to explore how system total cost affects islanding capability of a PV + battery system to supply energy to facilities. The finding shows that the decline of battery price not only reduces the lowest system total cost but also improves islanded system generation reliability. The proposed methodology for optimizing battery capacity added to PV array systems can make them grid-outage resilient and economically viable, which can be utilized as a decision-making tool for future PV + battery system expansion.
Highly concentrated electrolytes containing carbonate solvents with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) have been investigated to determine the influence of eliminating bulk solvent (i.e., uncoordinated to a Li+ cation) on electrolyte properties. The phase behavior of ethylene carbonate (EC)–LiTFSI mixtures indicates that two crystalline solvates form—(EC)3:LiTFSI and (EC)1:LiTFSI. Crystal structures for these were determined to obtain insight into the ion and solvent coordination. Between these compositions, however, a crystallinity gap exists. A Raman spectroscopic analysis of the EC solvent bands for the 3–1 and 2–1 EC–LiTFSI liquid electrolytes indicates that ∼86 and 95%, respectively, of the solvent is coordinated to the Li+ cations. This extensive coordination results in significantly improved anodic oxidation and thermal stabilities as compared with more dilute (i.e., 1 M) electrolytes. Further, while dilute EC–LiTFSI electrolytes extensively corrode the Al current collector at high potential, the concentrated electrolytes do not. A new mechanism for electrolyte corrosion of Al in Li-ion batteries is proposed to explain this. Although the ionic conductivity of concentrated EC–LiTFSI electrolytes is somewhat low relative to the current state-of-the-art electrolyte formulations used in commercial Li-ion batteries, using an EC–diethyl carbonate (DEC) mixed solvent instead of pure EC markedly improves the conductivity.
The Er-doped LiMnPO4/C cathode materials were synthesized by a sol-assisted hydrothermal synthesis method followed by annealing at a low temperature using maleic acid as chelating agent and carbon source for the first time. The structure and electrochemical performances of the obtained samples were investigated systematically including XRD, SEM, EDS, galvanostatic charge and discharge tests, cycle voltammetry and electrochemical impedance spectroscopy. Results show that the doped materials especially LiMn0.97Er0.03PO4/C tend to grow in the orientation of rectangle with the uniform particle size. Among all the samples, LiMn0.97Er0.03PO4/C delivers the highest discharge capacity of 142.5mAhg−1 at 0.05C and a high capacity retention of 90.8% after 100cycles at 1C. Even with the high current density of 5C, its capacity remains at 105.6mAhg−1 in comparison with 46.3mAhg−1 of LiMnPO4/C. Compared with LiMnPO4/C, the Er-doped samples demonstrate significantly enhanced electrochemical performance for lithium-ion batteries. This is likely due to the fact that the large ionic radius of erbium ions could enlarge the volume of lattice and alleviate the effect of Jahn-Teller, which is beneficial to improve Li-ion diffusion coefficient and reduce the charge transfer impedance. This material shows promising potential for use in high-voltage cathodes for lithium-ion batteries.