batterydata/paper-abstracts huggingface dataset:
Design and synthesis of capable anode materials that can store the large size K+ is the key of development for potassium–ion batteries. The low–cost and commercial expanded graphite with large particles is a graphite–derived material with good conductivity and enlarged interlayer spaces to boost the potassium ion diffusion coefficient during charge/discharge process. Thus, we achieve excellent anode performance for potassium–ion batteries based on an expanded graphite. It can deliver a capacity of 263 mAh g−1 at the rate of 10 mA g−1 and the reversible capacity remains almost unchanged after 500 cycles at a high rate of 200 mA g−1 with a coulombic efficiency of around 100%. The potassium storage mechanism is investigated by the ex situ XRD technique. This excellent potassium storage performance will make the expanded graphite promising anode candidate for potassium ion batteries.
Heat is produced after interruption of the current because of relaxation of concentration gradients in electrochemical systems. This heat of relaxation is termed heat of mixing. Two methods, one computational and one analytic approximation, for computing the heat of mixing are presented. In general, the magnitude of the heat of mixing will be small in materials with transport properties sufficiently high to provide acceptable battery performance, with the possible exception of heat of mixing within the insertion particles if the particle radius is large. In insertion materials, such as lithium insertion electrodes, the entropy of reaction may vary substantially with state of charge. The entropy of reaction accounts for a reversible heat effect which may be of the same order of magnitude as the resistive heating. Measurements for the entropy of reaction as a function of state of charge in LiCoO2, LiNi0.8Co0.2O2, and LiC6 are presented.
In parallel cell circuits within Lithium ion home storage systems, both the components as well as the topological structure of the circuit have an enormous influence on the current distribution among the individual cells and as consequence on the battery lifetime. For large battery assemblies welding techniques are often used for which a weldable current collector is needed. Due to the high specific resistance of the commonly used materials, this resistance measurably influences the current distribution. In this paper the current distribution in battery modules with Li ion cells connected in parallel has been measured and modelled. The cell internal resistance, the current collector resistance and the topology of the circuitry have been varied in order to determine the influence of each of these parameters on the current distribution. Model calculations for the cycle lifetime of battery modules have been performed assuming realistic charge and discharge profiles matching the conditions to be found in commercially available home storage systems. From the experimental data and the modeling results the most important parameters determining the homogeneity of the current distribution and the cycle lifetime of the battery modules have been extracted. Finally, design recommendations for Li ion batteries with cells connected in parallel are derived.
The present work elucidates synthesis and electrocapacitive performance of cobaltites viz. Co3O4, NiCo2O4, ZnCo2O4 and MnCo2O4 nanostructured particles synthesized using template free urea assisted hydrothermal method. Morphology and size of the synthesized cobaltites were examined by using scanning electron microscopy. Hierarchical structures namely fibrous and urchin-like microsphere were observed for the cobaltites. Electrochemical measurements were performed using standard three electrode system with 3M KOH electrolyte via cyclic voltammetry and galvanostatic charge-discharge methods. Amongst the cobaltite studied, NiCo2O4 displayed high surface area (46.05m2/g), high specific capacitance (173F/g at 5mV/s) and energy density (7Wh/kg). The specific capacitance of all the cobaltites decreased with the increase in scan rate. Furthermore, the specific capacitance showed invariance with the current density up to 5A/g. The cyclic stability of NiCo2O4 was studied up to 5,000 cycles and about 76% retention in charge storage capacity was observed. Among all cobaltites, the EIS measurements confirm superior performance of NiCo2O4 as it displays minimum impedance at all frequency. Furthermore, specific capacitance was compared for two and three electrode cells with NiCo2O4 as an electrode material. The hybrid density functional theory (DFT) calculations of the electronic density of states of Co3O4, NiCo2O4, ZnCo2O4 and MnCo2O4 was performed. The DFT calculation predicted narrow band gap for NiCo2O4 (∼1.4eV) which is smallest among all cobaltites studied here in. The superior electrocapacitive behavior of the NiCo2O4 is attributed to high surface area urchin like structure and its high electrical conductivity due to its narrow band gap amongst studied cobaltites.
Ionic conductivity is a foremost transport property that is extensively used to characterize and screen electrolyte systems. Although bulk measurements are done on the macroscopic scale, electrolytic conductivity has its foundation on molecular-scale interactions between solvent and ionic species. Correct interpretations of these molecular interactions and related quantities enable a balanced, comprehensive understanding of conductivity behavior with respect to system conditions (solvent composition, salt concentration and temperature). This work introduces a new methodology that achieves accurate predictions of electrolyte conductivity for a wide range of conditions, based on molecular, physical, and chemical terms. The formalism is universal, making it valid for aqueous and non-aqueous systems alike. The immediate application of the resultant model is candidate electrolytes for lithium-ion and sodium-ion batteries, although many other applications abound for systems that utilize liquid electrolytes. Conductivity predictions are compared to experimental data for a number of electrolytes over a wide range of conditions, demonstrating that exceptional accuracy is attained because the robust model captures multiple salient contributions to conductivity behavior. Model accuracy is well maintained over multi-solvent systems and for extended salt concentrations.
The electrochemical behavior of magnesium perchlorate in an ionic liquid, 1,2-dimethyl-3-octylimidazolium bis(trifluoromethanesulfonyl)imide, is characterized using RuO2 as the cathode and Mg foil as the anode material. Electrochemical results indicated that the maximum Mg content intercalated into RuO2 resulted in Mg0.25RuO2, with an initial capacity of 101mAh/g. X-ray diffraction studies of the Mg-intercalated RuO2 indicated a large expansion of the unit cell and a decrease from cubic to monoclinic symmetry. X-ray diffraction studies and structural analysis suggest a similarity between the structure of Mg0.25RuO2 and Li2RuO3. Charge/discharge experiments at a C/3 rate were performed vs. Mg metal. Results indicated that the capacity decreased significantly with cycling, most likely due to the strong interaction of Mg2+ with the oxide lattice of RuO2.
In this study, triplite 3.9V-LiFeSO4F in single step solid-state reaction with various precursors was synthesized by understanding the reaction pathway that it forms. The loss of fluorine during a heat treatment can be a main problem because it can cause the formation of non-fluorine compounds such as Li2Fe(SO4)2 phase, which are undesirable impurity phases. An additional fluorine source was used to compensate the loss of fluorine and led to the formation of highly-pure triplite LiFeSO4F. Furthermore, additional supplementation with sucrose as a carbon source produced highly-pure LiFeSO4F nano-particles, coated with a carbon layer. This resulting material can achieve superior rate capability up to 20C rate (3min discharge), ∼73mAhg−1 and have excellent capacity retention for 350 cycles at 1C charge/1C discharge rate even though the structure of triplite LiFeSO4F does not have an apparent long Li diffusion pathway due to a disordered Li/Fe distribution. These results demonstrate that triplite LiFeSO4F is a promising cathode material with respect to energy density and scalable synthesis capability. Furthermore, this solid-state reaction with additional fluorine source will open novel ways to further engineer the material properties of LiFeSO4F or other fluorine containing compounds.
In this paper we present the findings of a qualitative investigation of change trends in urban freight deliveries. The empirical material was gathered with urban freight (courier) company managers and drivers in Aotearoa New Zealand. It presents personal accounts of the everyday lived experiences of those intimately involved in the delivery of goods within the urban environment. Twenty-five interviews were conducted across four urban centres between June and September 2015. We use the four elements of the Energy Cultures Framework to explore what urban freight managers and drivers ‘have’, ‘do’ and ‘think’, and the pressures of an external context. Four interrelated themes are presented. 1. Online shopping and home deliveries, 2. Tracking and transparency, 3. New technologies, and 4. Meeting (changing) expectations, with evidence provided by way of verbatim quotations. The ‘mobility cultures’ concept is used to explore the relationships between the four themes, and to identify the key change trends that may affect the ability of the freight industry to contribute to a low-carbon transport transition. We conclude by signalling some policy implications and future research directions.
We report a case of rapidly progressive frontotemporal dementia presenting at age 33 years. At autopsy there was severe atrophy of the frontal and temporal lobes. Tau-positive Pick bodies, which ultrastructurally were composed of straight filaments, were present, accompanied by severe neuronal loss and gliosis. RD3, a tau antibody specific for the three-repeat (3R) isoforms, labeled the Pick bodies. ET3, a four-repeat (4R) isoform-specific tau antibody, did not label Pick bodies, but highlighted rare astrocytes, and threads in white matter bundles in the corpus striatum. Analysis of the tau gene revealed an L266V mutation in exon 9. Analysis of brain tissue from this case revealed elevated levels of exon 10+ tau RNA and soluble 4R tau. However, both 3R and 4R isoforms were present in sarkosyl-insoluble tau fractions with a predominance of the shortest 3R isoform. The L266V mutation is associated with decreased rate and extent of tau-induced microtubule assembly, and a 3R isoform-specific increase in tau self assembly as measured by an in vitro assay. Combined, these data indicate that L266V is a pathogenic tau mutation that is associated with Pick-like pathology. In addition, the results of the RD3 and ET3 immunostains clearly explain for the first time the presence of both 3R and 4R tau isoforms in preparations of insoluble tau from some Pick's disease cases.
Christensen B, Colella B, Inness E, Hebert D, Monette G, Bayley M, Green RE. Recovery of cognitive function after traumatic brain injury: a multilevel modeling analysis of Canadian outcomes. Objective To ascertain patterns of cognitive recovery during the first year after traumatic brain injury (TBI). Specifically, differential recovery across cognitive domains was investigated. Design Prospective, longitudinal, naturalistic, 1-year follow-up study. Setting Large, urban inpatient neurorehabilitation program. Participants Patients (N=75) with moderate to severe TBI. Interventions Not applicable. Main Outcome Measures Patients with TBI were followed over the course of 1 year, during which participants' neuropsychological status was repeatedly evaluated at 3 time points (2, 5, and 12 months postinjury). Results Multilevel modeling results were consistent with previous research, demonstrating that recovery in the first year postinjury is asymptotic in nature, with more accelerated recovery occurring during the first 5 to 6 months. Importantly, results also suggest that recovery is not uniform across cognitive domains. From 2 to 5 months postinjury, steeper recovery curves were revealed for indices of memory, speeded executive function, verbal abstraction, and manual dexterity relative to untimed tests of executive function and word knowledge. Recovery trajectories did not significantly vary as a function of cognitive domain over the course of the last 5 to 12 months. Conclusions These results are the first to explore trajectories of recovery directly as a function of multiple cognitive domains. They are expected to have implications for rehabilitative efforts as well as our understanding of the architecture of natural recovery after TBI.
A load-leveling (LL) system is needed for the effective use of electric power to preserve the environment in Japan. Although the valve regulated lead-acid (VRLA) battery is considered to be one of the suitable candidates, high requirements of long cycle life such as 2000 cycles or a calendar life of 7years needed to be solved. We are currently developing a new VRLA battery for this application, and have succeeded in achieving over 2000 cycles with a 35Ah class VRLA battery. It was confirmed by the detailed investigation after a cycling test of the battery that this cycle performance was achieved by improving the charge acceptance of the negative plate, avoiding the grid corrosion by applying an optimized charge condition.
A distributed control method for residential battery energy storage (BES) units coupled with photovoltaic (PV) systems is presented. The objective is to utilize customer owned BES units for solving the over-voltage issues caused by high PV penetration without significantly affecting the BES owners local objectives. 24 h ahead active power set points of the BES unit are calculated by an optimization based scheduling algorithm. The objective function is locally decided and the optimization is performed at the local level. The BES units are charged from the excess energy from the PV systems mostly during the period the grid is under risk of over-voltage. If the set points that were calculated by the optimization, turn out not to be able to maintain the voltages within the statutory limits in real time operation, the active power set points are modified. Reactive power is also utilized when active power is not sufficient. The new set points are calculated by a central controller. The performance of the proposed method is validated in a simulation study. It is shown that the residential BES units can successfully be utilized for solving over-voltage issues without significantly affecting the primary needs of the BES owners.
This paper presents an assessment and evaluation of the costs of operation and maintenance (O&M) in a real PV rural electrification (PVRE) programme, with the aim of characterizing its costs structure. Based on the extracted data of the 5-years operational costs of a private operator, the programme has been analyzed to take out the most relevant costs involved in the O&M phase as well as the comparative appraisal between the 3 main activities: installation, O&M and management. Through this study we try to answer to the new challenge of decentralized rural electrification based on larger programmes (with tens of thousands of SHSs) and longer maintenance and operation periods (at least 10 years).
Impedance measurements of both electrodes of a flooded OEM SLI battery at various SOC and with various direct currents have been measured. For each part of the impedance spectra, an electrochemical process is proposed and implemented in a simulation model. By simulation of impedance spectroscopy, spectra of the model are obtained and compared with the measurement. In the first part, the focus was put on inductive semicircles, while in this second part, concentration limitation and its appearance in impedance spectra is investigated.
The present study demonstrated that the lower-extremity muscle performance in Chinese community-dwelling postmenopausal women with lower bone mineral density (BMD) was positively associated with hip BMD and negatively associated with estimated fracture risk.
Introducing diffusion-controlled battery materials to supercapacitors, can significantly enhance the energy density of supercapacitors, which however encounter depressed power density due to the intrinsic sluggish charge storage kinetics of battery materials. This problem can be efficiently solved by modifying the microstructure, and enable capacitive controlled charge storage mechanism in the battery materials. In this work, a novel interface-rich core-shell structure with (NH4)(Ni,Co)PO4·0.67 H2O nanosheets @ single crystal microplatelets (NH4)(Ni,Co)PO4·0.67 H2O (NCoNiP@NCoNiP) is constructed via a facile two-step hydrothermal method, taking advantage of etching induced Kirkendall effect and Ostwald ripening. This unique structure can enable the extrinsic pseudocapacitance by providing extra charges (e.g. holes, electrons or voids) on the interfaces, and realize synergy and fast charge storage. Specifically, a maximum specific capacity of 190.3 mAh g−1 and ultrahigh rate performance with capacity retention of 96.1% from 1 to 10 A g−1 in a three-electrode test. The kinetic analysis indicates that the electrochemical response of the hybrid battery-supercapacitor storage devices shows obvious characteristic of supercapacitor especially at high scanning rates. Simultaneously, the hybrid battery-supercapacitor devices based on NCoNiP@NCoNiP exhibits a high energy density of 44.5 Wh kg−1 at a power density of 150 W kg−1, which maintains 30 Wh kg−1 at high power density of 7.4 kW kg−1 with capacitance retention 77.5% after 7000 cycles. This work provides a novel strategy for the application of battery materials in high power devices, by enabling the capacitive charge storage mechanism of battery materials through nanostructure engineering.
This paper outlines the results of a survey which was carried out to identify Düzce University prep class students’ attitudes towards English language learning. 400 non-English major students who took English in preparatory classes before they studied in their department participated in the research. A five point Likert Scale based on Gardner's Attitude/Motivation Test Battery was administered to all students to find out what attitudes students had towards English language learning. Frequencies and t-test were used in analyzing the data. This study indicates that students are anxious when they speak in classroom, nonetheless, they are willing to learn English, and there is statistically significant difference between the anxiety level of female and male students towards learning English.
Background The Personal and Social Performance (PSP) scale is a widely used tool to evaluate adults with schizophrenia; however, more studies are needed regarding its usefulness in the assessment of adolescent patients, since the evaluation of their functioning could require adaptations according to development. Objective To examine construct validity, convergent validity, internal consistency and interrater reliability of the PSP in a sample of Mexican adolescents with schizophrenia. Methods A total of 40 patients with a DSM-IV diagnosis of schizophrenia or schizophreniform disorder were evaluated with PSP, CGAS, PANSS and the MATRICS battery. Construct and convergent validity were determined by the correlation between PSP with PANSS factors, MATRICS dimensions and CGAS. In addition, reliability was evaluated with Cronbach's alpha and intraclass correlation coefficients. Results PSP scores correlated with negative, excitement and cognitive factors of PANSS, CGAS as well as MATRICS domains. The PSP also showed high internal consistency and interrater reliability. Conclusions The PSP is a valid and reliable instrument for the assessment of adolescent patients.
A novel porous sulfur/polypyrrole/multiwalled carbon nanotube composite (S/PPy/MWNT) was synthesized via in situ polymerization of pyrrole monomer with nano-sulfur and MWNT aqueous suspension followed by a low temperature heat-treatment. Scanning electronic microscopy revealed the formation of a highly hierarchical mesoporous and macroporous structure. High resolution transmission electronic microscopy confirmed homogeneous dispersion of S, PPy and MWNT in the composite. In this composite, polypyrrole with its high adhesion ability to MWNT acts as a conductive binder to connect sulfur and MWNT matrix, as well as absorbs polysulfides into its porous structure positively affecting the composite performance as a cathode in a Li/S cell. The resulting S/PPy/MWNT composite cathode exhibited greatly enhanced cyclability and delivered a reversible discharge capacity of 751 mAh g−1 after 100 cycles at 0.2C.
Publisher Summary The chapter explores the physical medium of wireless local area networks (WLANs), and the ways in which it can and must be manipulated to have an effective WLAN. This coverage ranges from theory to practice while conducting site surveys in advance of WLAN setup. The most important part of WLAN implementation is deployment planning. A poorly planned deployment is much worse than no deployment at all. If appropriate planning is not done, wireless LAN deployment can be a complete failure because of its inability to function or its inability to properly serve user needs. Site surveys are critical to both the initial planning stages of Radio Frequency deployment and the ongoing maintenance of the WLAN. These are explored in detail in the chapter and a sample site survey form is provided to get one started. Interference detection and how this step of planning can help one to successfully deploy WLAN are also discussed in the chapter.
The mechanism of cobalt electrodeposition cobalt on glassy carbon from an aqueous sulphate solution has been studied using electrochemical techniques such as cyclic voltammetry, linear stripping voltammetry (LSV) and chronoamperometry, as well as contact mode atomic force microscopy (AFM) which has allowed the complementary determination of morphological detail of the resulting deposits. The influence of power ultrasound (20 kHz) was then studied. At suitably high overpotentials cobalt electrocrystallisation under silent conditions proceeds via a diffusion controlled mechanism and was analysed using the Scharifker and Hills model for potentiostatic growth: at low overpotentials (ca. −1.0 V vs. SCE) growth occurred under charge transfer control. Nucleation was found to be more ‘progressive’ in character at −1.0 V vs. SCE while at elevated overpotentials (more negative than −1.25 V) an ‘instantaneous’ nucleation behaviour was determined. Sonication favoured ‘instantaneous’ deposition and generally increased the rate of cobalt deposition, although ablation was dominant at small electrode—tip/horn separations. AFM images confirmed these findings, showing cobalt clusters of varying sizes at low overpotential and silent conditions, and more uniformly sized clusters at higher overpotentials, particularly when sonication was applied.
Lithium ion batteries (LIB) have achieved great success as energy supply systems in portable devices and in electrical vehicles. Identifying the local chemical structures of elemental lithium in lithium compounds is beneficial for improving understanding of battery components and performance. Herein, a library of Li K-edge X-ray absorption near edge structure (XANES) of lithium compounds relevant to Li-ion batteries is reported. Materials described include lithium metals (anode), Li-containing cathodes, electrolytes and solid electrolyte interphase (SEI). The results illustrate the characteristic spectral features stemming from the various electronic structures and chemical environment of lithium atoms for each and every possible battery component. XANES spectra of Sn based anode after discharging reveal the appearance of Li2CO3 on electrode surface. X-ray damage on sensitive lithium species is also assessed; the results reveal that more attention should be paid to irradiation effects to conduct XANES measurements for battery materials properly.