batterydata/paper-abstracts huggingface dataset:
Porous hollow structures have attracted tremendous interests due to their geometrical beauty, unique structural features and fascinating physicochemical properties. In the present work, we developed a general procedure for the synthesis of hollow nanostructured carbon-wrapped cerium oxide (CeO2/C) via a microwave hydrothermal process without any surfactants or hard templates. The electrochemical performances of CeO2/C specimen were tested as anode materials in lithium ion batteries. The results showed that CeO2/C hollow spheres exhibited an exceptional cyclic stability with a high reversible capacity of 313mA h g−1 after 500 cycles at a high current density of 1000mAg−1 without signs of further degradation and also presented an excellent rate performance from 1000 to 10000mAg−1. The improved performances were attributed to the homogeneous carbon with 3D network structure in hollow spheres and the Ce3+ in the oxygen-deficient fluorite-like CeO2-x on the surface of ceria nanoparticles, which enhanced the conductivity of CeO2 hollow spheres, suppressed the aggregation of active particles and reduced the apparent activation energy to facilitate the kinetics of Li+ insertion-extraction. The unique hollow structure of CeO2 wrapped by conductive carbon have made CeO2 a promising candidate for future applications in various metal oxide electrodes to mitigate the mechanical degradation and capacity fading, critical for developing advanced electrochemical energy storage systems with long-cycle life and high-rate performance.
This paper investigates the stochastic properties of the consumption–income ratio for a sample of 23 OECD countries over the period 1960–2005. For that purpose, we employ a battery of recently developed panel unit root and stationarity tests. Our findings from panel unit root tests which do not control for structural breaks appear in line with those from previous studies since they are clearly supportive of the unit root hypothesis. In stark contrast stand the results obtained from the application of a panel stationarity test with multiple breaks, which support the existence of regime-wise stationarity in OECD consumption–income ratios once we control for cross-sectional dependence through bootstrap methods. These findings are reinforced by the median-unbiased estimates of half-lives obtained from impulse-response functions which are found to be finite for the 23 OECD countries.
In this work, we are presenting both lithium and sodium ion capacitors (LIC and NIC) entirely based on electrodes designed from recycled olive pit bio-waste derived carbon materials. On the one hand, olive pits were pyrolized to obtain a low specific surface area semigraphitic hard carbon to be used as the ion intercalation (battery-type) negative electrode. On the other hand, the same hard carbon was chemically activated with KOH to obtain a high specific surface area activated carbon that was further used as the ion-adsorption (capacitor-type) positive electrode. Both electrodes were custom-made to be assembled in a hybrid cell to either build a LIC or NIC in the corresponding Li- and Na-based electrolytes. For comparison purposes, a symmetric EDLC supercapacitor cell using the same activated carbon in 1.5 M Et4NBF4/acetonitrile electrolyte was also built. Both LIC and NIC systems demonstrate remarkable energy and power density enhancement over its EDLC counterpart while showing good cycle life. This breakthrough offers the possibility to easily fabricate versatile hybrid ion capacitors, covering a wide variety of applications where different requirements are demanded.
Porous Mn3O4 nanoparticles with tunable microstructures are synthesized from Mn(AcO)2·4H2O with Pluronic F127 as a dispersant. The amount of copolymer served as the surfactant in the precursor solution is varied to change/tune the specific surface area/porosity of Mn3O4. The textural and electrochemical properties of porous Mn3O4 nanoparticle are systematically characterized by means of the N2 adsorption/desorption isotherms, scanning electron microscopic (SEM), transmission electron microscopic (TEM), X-ray diffraction (XRD), and voltammetric analyses. The interactions between manganese precursor and triblock copolymer can be used to control the microstructures of resultant oxides. Mn3O4 nanoparticles with tunable porosity and high surface area achieve the excellent capacitive performances (e.g., high-power characteristics and impressive capacitance retention) for next generation supercapacitors. The specific surface area indicating the electrochemically active sites for charge storage/delivery as well as the pore structure indexed by the BJH pore volume, which affects the ion transportation and electrolyte permeation, have been demonstrated to be the key factors determining the capacitive performances of Mn3O4 in the low-rate and high-rate processes, respectively.
Development of battery technology is making battery electric heavy duty trucks technically and commercially viable and several manufacturers have introduced battery electric trucks recently. However, the national and sectoral differences in freight transport operations affect the viability of electric trucks. The aim of this paper is to develop a methodology for estimating the potential of electric trucks and demonstrate the results in Switzerland and Finland. Commodity-level analysis of the continuous road freight survey data were carried out in both countries. As much as 71% of Swiss road freight transport tonne-kilometers may be electrified using battery electric trucks but Finland has very limited potential of 35%, due to the use of long and heavy truck-trailer combinations. Within both countries the electrification potential varies considerably between commodities, although in Finland more so than in Switzerland. Commodities which are constrained by payload volume rather than weight and are to large extent carried using medium duty or <26t rigid trucks trucks seem to provide high potential for electrification even with the current technology. Electric trucks increase the annual electricity consumption by only 1–3%, but truck charging is likely to have a large impact on local grids near logistics centres and rest stations along major roads. A spatial analysis by routing the trips reported in the datasets used in this study should be carried out. Future research should also include comparison between the alternate ways of electrifying road freight transport, i.e. batteries with charging, batteries with battery swapping and electrified road systems.
Research on the neural basis of working memory (WM) has generally focused on cortical regions, specifically frontal and parietal areas. Comparatively, evidence of a possible involvement of deep gray matter structures, that are parts of cortico-cortical circuits linking anterior and posterior cortical areas, is far less clear. The goal of the present study is to test the hypothesis that individual structural variations within deep gray matter structures may affect the cortical networks involved in WM. To this aim, a large sample (n=181) of healthy subjects underwent a high-resolution structural magnetic resonance imaging (MRI) and a diffusion tensor imaging (DTI) scan protocol. Data of micro- (mean diffusivity, MD) and macro- (volume) structural variations of six bilateral deep gray matter structures (thalamus, caudate nucleus, putamen, hippocampus, amygdala and pallidum) and lateral ventriculi volume were analyzed in association with score in a WM (the so-called n-back task) and other neuropsychological tasks. Results showed that increased MD of bilateral thalami was the only structural parameter that significantly correlated with reduced WM performance. In particular, a voxel-by-voxel analysis revealed that the greater percentage of voxels showing significant anticorrelation between WM score and MD values were localized in those thalamic nuclei projecting to prefrontal and posterior parietal cortices. Results highlight the specific involvement of thalamus microstructure, not volume, in modulating WM performance, possibly by regulating the connections among cortical areas that are recruited during WM tasks.
The nickel sulfide, Ni3S2, was examined as a potential cathode material of the all-solid-state-lithium-batteries using thio-LISICON, Li2S–GeS2–P2S5, as the solid-electrolyte. Ni3S2and Li2S–GeS2–P2S5 system, was synthesized with a new sintering system, which proceed under a flowing argon in the reusable quartz tube. The highest ionic conductivity 2.39 × 1 0 − 3 S cm−1 was observed for a sample prepared at 700 °C with 10% of excess P2S5, and bear comparison with the maximum conductivity reported for the thio-LISICON, Li3.35Ge0.35P0.65S4. An all-solid-state-lithium-battery based on, Ni3S2/Li3.35Ge0.35P0.65S4/Li–Al alloy, showed electrochemical capacities of greater than ∼ 300 mAh g−1 after 30 cycles. The cycling performances of the cells were found to be dependent on the Ni3S2/thio-LISICON compositions in the cathode mixture, with a cell containing 60 wt.% of Ni3S2 exhibiting the most stable reversible capacities. As the depth of the first discharge capacity also influences the cycling properties, Ni3S2 consumed during the discharge reaction may play an important role in the nickel reduction mechanism.
Herein, we report on Li3V2(PO4)3 (LVP)/reduced graphene oxide (rGO) multilayer composites prepared via a sequential adsorption method and subsequent heat treatment, and their use as cathodes for high-rate lithium-ion batteries. The sequential adsorption process includes adsorbing oppositely charged components of anionic inorganic species and cationic head of a surfactant adsorbed to graphite oxide sheets, which is a key step in the fabrication of the LVP/rGO multilayer composites. The multilayer structure has open channels between the highly conductive rGO layers while achieving a relatively high tap density, which could effectively improve the rate capability. Consequently, the LVP/rGO multilayer composites exhibit a high tap density (0.6 g cm−3) and good electrochemical properties. Specifically, in the voltage range of 3.0–4.3 V, the composite exhibits a specific capacity of 131 mAh g−1 at 0.1C, a good rate capabilities (88% capacity retention at 60C), and long cycling performance (97% capacity retention after 500 cycles at 10C). Moreover, in the extended voltage range of 3.0–4.8 V, it exhibits a high specific capacity of 185 mAh g−1 at 0.2C, a good rate capability (66% capacity retention at 30C), and stable cycling performance (96% capacity retention after 500 cycles at 10C).
Improving sulfur redox kinetics and cycling stability of lithium-sulfur (Li-S) batteries through controlling inherent dissolution of polysulfides and following shuttle effect is pivotal for further progress of this promising electrochemical system. In this work, three-dimensional porous microspheres composed of nanosized sulfur particles, nitrogen-doped oxygen-deficient TiO2-x nanorods and reduced graphene oxide (N-TiO2-x/RGO/S) were synthesized as sulfur host material for the first time in spray-drying process. The microspheres construction with void spaces mitigated volumetric expansion upon charge/discharge cycling and improved sulfur utilization. Furthermore, the N-TiO2-x nanorods enhanced the conductivity of the material and exhibited strong capability for adsorption and the migration of lithium polysulfides, which was demonstrated by the density functional theory (DFT) calculations. Due to such advantages, the N-TiO2-x/RGO/S cathode delivered excellent rate capability and stable cycle performance at 1.0 C over 300 cycles with a specific capacity about 700 mAh g-1. This novel design and preparation strategy also contributes to the materials engineering and structural design towards remarkable improvement of electrochemical performance of energy storage systems.
Tin oxide (SnO2) has received great attention as promising anode for lithium ion batteries because it offers a high theoretical capacity (ca. 782 mAh g−1 for Li4.4Sn) and a safe discharge potential versus Li/Li+ in comparison to commercialized graphite anodes, whereas it also suffer from the drawbacks of the huge volume change and low electronic conductivity during lithiation/delithiation processes. Herein, we have prepared a SnO2/C composite of ultrasmall SnO2 nanoparticles (∼6 nm and ∼59.4% by weight) embedded in carbon matrix (denoted as SnO2/C-59) by a facile hydrothermal and subsequent carbonization approach. In this peculiar architecture, uniform distribution of SnO2, and electronic conductivity of carbon matrix, which can effectively solve the problems of pulverization, loss of electrical contact and particle aggregation during cycling, therefore contributing to excellent lithium storage and cycling stability. A reversible capacity of 839.1 mAh g−1 is obtained at 200 mA g−1 after 217 cycles. More importantly, 712.8 mAh g−1 can be obtained at 800 mA g−1 even after 378 cycles.
Polyacrylonitrile/poly(methyl methacrylate) (PMMA) fibers containing graphene are prepared by the electrospinning method, and hierarchical porous carbon nanofibers (CNFs) are obtained after subsequent heat treatment. The hierarchical porous CNFs have an improved structure and properties because of the increased surface area, unique nanotexture and increased electrical conductivity due to the dispersion of graphene. The carbonized fiber exhibits a high surface area (over 500m2 g−1) as result of the narrow ultramicro- and mesopore size distributions (centered at approximately 0.7 and 3.7nm, respectively), and a broad mesopore size distribution ranging from 10 to 50nm. The hierarchical pore structures are introduced by the evolution of small gas molecules during the decomposition of the PMMA during heat treatment. The highest specific capacitance of the CNFs is 128Fg−1, and the energy densities are 16.0–21.4Whkg−1 in an aqueous solution and 75.0–58.2Whkg−1 in an organic electrolyte over a power density range of 400–20,000Wkg−1. Under constant current charging/discharging at 1mAcm−2 for 100 cycles, the stability of the CNFs in a 6M KOH aqueous electrolyte decreases by ∼17% compared with the initial specific capacitance value.
LiNO3 is selected as the additive to modify the electrolyte for lithium sulfur battery. The cycling efficiency (EFF) shows that LiNO3 additive is favorable for the lithium deposition and dissolution on the Cu foil. SEM and XPS are applied to analyze the surface changes of the lithium cycled in the electrolytes. The LiNO3 additive is conducive for the construction of protective film on the surface of the lithium anode. Lithium sulfur batteries are also cycled with the 0.4M LiNO3 modified electrolyte. The lithium sulfur battery tested shows improved cycling performance with the coulombic efficiency above 95% and highly stable reversible discharge capacity of ca. 527mAhg−1 after 50 cycles.
KEYWORDS Smart clothing, electrically conductive fibre, connection, accelerated reliability test, wearing comfort
Laboratory-scale electrochemical capacitor cells with bound activated carbon electrodes and acetonitrile-based electrolyte were aged at various elevated constant cell voltages between 2.75V and 4.0V. During the constant voltage tests, the cell capacitance as well as the capacitance and resistance of each electrode was determined. Following each aging experiment, the cells were analyzed by means of electrochemical impedance spectroscopy, and the individual electrodes were characterized by gas adsorption and X-ray photoelectron spectroscopy. At cell voltages above 3.0V, the positive electrode ages much faster than the negative. Both the capacitance loss and resistance increase of the cell could be totally attributed to the positive electrode. At cell voltages above 3.5V also the negative electrode aged significantly. X-ray photoelectron spectroscopy indicated the presence of degradation products on the electrode surface with a much thicker layer on the positive electrode. Simultaneously, a significant decrease in electrode porosity could be detected by gas adsorption.
Zinc powders containing Bi, In and either Mg or Al were analyzed to determine chemical and morphological differences. Morphology and chemistry may influence the reactivity of Zn powders in the basic environment found inside alkaline batteries. Increased reactivity leads to increased Zn corrosion, increased hydrogen gas evolution, and possibly leakage of the battery electrolyte. The surface chemistry of the powders was examined using Auger electron spectroscopy, X-ray photoelectron spectroscopy, and atomic absorption spectroscopy to check for surface ZnO. Powder chemistry was measured using an electron probe micro analyzer equipped with an energy dispersive X-ray analyzer. Inert gas fusion determined the bulk oxygen content. Morphology studies included powder sieving for size determination, examining loose powders with a scanning electron microscope (SEM), and determining surface areas via Brunauer, Emmet, and Teller (BET) analyses. SEM images showed differences in powder shapes and surface conditions between passed and failed powders. Powders exhibiting smooth surfaces and regular shapes were more likely to pass gas testing. However, pass/fail gas test results could not be correlated to powder chemistry, powder size, or surface area. Powder roughness and irregularity may indicate an increase in the number of active sites such as peaks and barbs versus particles with smooth surfaces.
In 2009, an estimated 585 million people had no access to electricity services in sub-Saharan Africa. Unlike many other regions of the world, under current assumptions, that figure is expected to rise significantly to about 652 million by 2030-an unsustainable and unacceptable situation. Knowing of the intrinsic linkages between access to energy services and development, national governments and regional organisations have identified the urgent need for accelerated electrification rates. Some of the established and emerging concepts, systems and technologies grouped under the term ‘Smart Grids’ may offer an important contribution to achieving universal access to electricity. We argue that these Smart Grid advances may enable sub-Saharan African countries to leapfrog elements of traditional power systems and accelerate and improve electrification efforts. We introduce the notion of Just Grids to reflect the need for power systems to contribute towards equitable and inclusive economic and social development without marginalising the poor. The paper reviews the literature, and identifies specific options that could be implemented in sub-Saharan Africa. After selecting criteria that focus on potential impact as well as requirements for their implementation, a qualitative first-pass assessment of the potential of these options is made. This paper provides support for policy development, and suggests areas for further, more detailed research.
In lithium-ion batteries, several electrical and physical parameters are responsible for the degradation of the electrode materials. Here the application of Kelvin probe microscopy (KPM) is demonstrated to measure the charge sustaining capability of the LiFePO4 cathode under aged and unaged conditions. The aged sample shows lower surface potential than the unaged sample, which can be attributed to changes in physical and chemical properties including particle size, phase of the surface layer and nanocrystalline deposits.
Novel polymeric gel electrolytes consisting of poly(ethylene oxide)–modified poly(methacrylate) (PEO–PMA) with magnesium imide (Mg[(CF3SO2)2N]2) as the electrolytic salt and mixed alkyl carbonates as the plasticizer have been prepared by photo-induced radical polymerization. The polymeric gel film was flexible and self-standing with proper mechanical strength. The ionic conductivity of the polymeric gel film was about 10−3 S cm−1 at room temperature. The ionic conductivity increased with the content of the plasticizer, ethylene carbonate (EC) and dimethyl carbonate (DMC), in the complex, while the mechanical strength of the gel film decreased with the increase in the plasticizer. The highest conductivity was obtained for the composition of 75 wt.% of the plasticizing component, EC+DMC dissolving Mg[(CF3SO2)2N]2 in the gel. The applicability of the present gel film to a rechargeable battery system was examined by a prototype cell consisting of Mg-doped V2O5 and V2O5 (or MnO2) as the negative and positive electrodes, respectively.
Piezoelectric polymer nanocomposites are prepared to improve the dielectric properties of polyvinylidene fluoride (PVDF) as micropower generators. Polyaniline (PANI) was chosen as a filler material to prepare the nanocomposites. PVDF-PANI nanocomposite films were prepared using the solvent cast method with different volume fractions of PANI varying from 0.04 to 0.06%. The films were then characterised for structural, mechanical and surface morphological properties using X-ray diffraction, differential scanning calorimeter, Raman spectra, Infrared spectra, tensile testing and scanning electron microscopy. X-ray diffraction analysis shows that the prepared PVDF-PANI films were in beta-phase. DSC scans indicate that the degree of crystallinity in PVDF-PANI has improved. Raman and Infrared spectrum further confirm the presence of beta-phase in PVDF-PANI film. Tensile properties of PVDF-PANI films show good mechanical properties. The surface feature shows that PANI is uniformly distributed in PVDF and also results in the disappearance of spherulites. The influence of volume fractions of PANI in PVDF on the dielectric properties were analysed. The results showed that the dielectric permittivity of PVDF-PANI (137.36) was much higher than that of PVDF (12). The sensitivity of these films were studied by the application of pressure, and it was observed that the voltage response of the film sensor is 12.4 V pk–pk, which is steady with the constant application of 1.85 kg weight. PVDF-PANI film sensor shows higher sensitivity with a longer period of time. These films were tested to use as micropower generators when coupled with supercapacitors.
LiNi0.91Co0.09O2 and LiNi0.86Co0.09Mg0.05O2 phases were comparatively cycled in 4/5 ‘A’-size lithium-ion cells (500 cycles, 60°C, C rate, 2h floating at 4.1V at each charge). The MgCo substituted positive electrodes exhibit a very small capacity fading versus the Co substituted one. Comparative Rietveld refinements of the XRD patterns before and after cycling show unambiguously that an irreversible migration of Mg2+ ions from the slabs to the interslab spaces occurs upon cycling. The variation of the cell parameters of the Li x Ni0.86Co0.09Mg0.05O2 deintercalated phases, obtained during the 1st and the 501st charges, were determined. The smaller changes observed after the Mg-migration suggest that the mechanical constraints typically observed during lithium intercalation–deintercalation are reduced by the simultaneous presence of magnesium ions in the lithium sites and of vacancies in the slabs, leading to a smaller capacity fading.
When I completed my Neuropsychology “post doc” in 1977, I never thought I would need this type of reference as I attended to the needs of persons with traumatic brain injury, cerebrovascular accidents and spinal cord injury. However as society has “advanced” towards more entitlements, financial awards for liability claims and a desire for unrealistic financial gain in business and finance, it is no wonder that individual clients may choose to mask genuine effort or exaggerate symptoms in an attempt to achieve maximum benefits.
The paper reviews properties of room temperature ionic liquids (RTILs) as electrolytes for lithium and lithium-ion batteries. It has been shown that the formation of the solid electrolyte interface (SEI) on the anode surface is critical to the correct operation of secondary lithium-ion batteries, including those working with ionic liquids as electrolytes. The SEI layer may be formed by electrochemical transformation of (i) a molecular additive, (ii) RTIL cations or (iii) RTIL anions. Such properties of RTIL electrolytes as viscosity, conductivity, vapour pressure and lithium-ion transport numbers are also discussed from the point of view of their influence on battery performance.