batterydata/paper-abstracts huggingface dataset:
Development of supercapacitors with high energy density and long cycle life using sustainable materials for next-generation applications is of paramount importance. The ongoing challenge is to elevate the energy density of supercapacitors on par with batteries, while upholding the power and cyclability. In addition, attaining such superior performance with green and sustainable bio-mass derived compounds is very crucial to address the rising environmental concerns. Herein, we demonstrate the use of watermelon rind, a bio-waste from watermelons, towards high energy, and ultra-stable high temperature green supercapacitors with a high-voltage ionic liquid electrolyte. Supercapacitors assembled with ultra-high surface area, hierarchically porous carbon exhibits a remarkable performance both at room temperature and at high temperature (60 °C) with maximum energy densities of ∼174 Wh kg−1 (25 °C), and 177 Wh kg−1 (60 °C) – based on active mass of both electrodes. Furthermore, an ultra-high specific power of ∼20 kW kg−1 along with an ultra-stable cycling performance with 90% retention over 150,000 cycles has been achieved even at 60 °C, outperforming supercapacitors assembled with other carbon based materials. These results demonstrate the potential to develop high-performing, green energy storage devices using eco-friendly materials for next generation electric vehicles and other advanced energy storage systems.
The high voltage spinel LiNi0.5Mn1.5O4−δ films were obtained by pulsed laser deposition. The effects of oxygen deficiency, annealing treatment, and film thickness on microstructure, morphology and electrochemical properties were investigated. We showed that tuning the oxygen pressure and annealing treatment allows modifying the oxygen film stoichiometry. Trying to determine the oxygen stoichiometry in thin films, a series of oxygen-deficient spinel “LiNi0.5Mn1.5O4−δ ” powder samples by quench steps from different temperatures were prepared. It is demonstrated that powders and thin films presenting similar cell parameters, namely related to the oxygen stoichiometry, show similar electrochemical profiles. Meanwhile, the compatibility of electrolyte with substrate and the stability of the target were also investigated.
Nickel vanadate (Ni3V2O8, NVO) nanoparticles (NPs) with a typical size of 30nm were prepared through a zeolitic imidazolate framework (ZIF) intermediate precipitation method using water as a solvent. The intermediate and the NVO obtained after annealing the intermediate were systematically characterized using various techniques. When tested as an anode for Li-ion batteries (LIBs), the electrode displayed stable specific capacities of 940 and 305mAhg−1 at 1 and 5Ag−1, respectively, after 400 and 1000cycles. Additionally, a very high reversible capacity of 1024mAhg−1 was observed after 525cycles, during which high current densities of 2 and 0.5Ag−1 alternated every 100cycles. The long cycling rate capability with repeated sets, confirm the structural stability of the material, which was prepared through a facile and eco-friendly procedure.
Liquid metals (LM) and alloys that feature inherent deformability, high electronic conductivity, and superior electrochemical properties have attracted considerable research attention, especially in the energy storage research field for both portable devices and grid scale applications. Compared with high temperature LM systems requiring rigorous thermal management and sophisticated cell sealing, room temperature LMs, which can maintain the advantageous features of liquids without external energy input, are emerging as promising alternatives to build advanced energy storage devices. Moreover, compared with high-temperature liquid metal alternatives, RT-LMs are free of thermal management, corrosion, and sealing issues. In this perspective, we summarize recent advances, analyze current challenges, and provide prospects of the RT-LM systems as electrodes for rechargeable batteries. Starting with an introduction of LM systems and their features, we present the status of the development of liquid metal anodes. Theoretical and experimental explorations of mechanisms including phase equilibria, wetting behavior, and alloy deposition behavior in a battery using liquid metal electrodes (LME) are provided to guide the battery design. Taking Na–K alkali metal alloys and Ga-based fusible alloys as two model LME systems, different battery designs are presented along with mechanistic discussions on cathode dependence, interfacial chemistry, and the multi-cation effect. In addition, other possible battery designs, major challenges, and possible opportunities for further developments of the RT LM-based energy storage systems are also discussed in the end.
Electrolyte optimization for both best performance and low use of materials is described in this paper. Electrochemical performance and material utility are reported to achieve the goal of optimal combinations of salt concentration and solvent ratios for several solvent mixtures. A lithium 4,5-dicyano-2-trifluoromethanoimidazolide (LiTDI) salt was used for its thermal stability, ease of handling (stable in the presence of air and moisture) and high ionic conductivity at low concentration in solvents. Solvent mixtures were chosen based on industrial practice and performance at low temperature. The conductivity dependence of salt concentration is reported. In all systems, low concentration onset and a broad range of high conductivity was observed. Lithium cation transference numbers were measured for highly conductive samples and used as the secondary parameter in the optimization procedure. Both high ionic conductivity and transference number values were recorded, even for samples with low salt content: 0.3molkg−1 LiTDI in 1EC:2EMC (σ=4.18mScm−1, TLi+ =0.544) and 0.4molkg−1 LiTDI in EC:DMC:EMC (σ=4.69mScm−1, TLi+ =0.455). Cycling with anodic material was also carried out, showing good capacity for retention of the mixtures chosen containing average salt concentrations. Hence, material savings in comparison to other commercially available lithium salts is possible.
Direct volume rendering has been an active area of research for over two decades. Transfer function design remains a difficult task since current methods, such as traditional 1D and 2D transfer functions, are not always effective for all data sets. Various 1D or 2D transfer function spaces have been proposed to improve classification exploiting different aspects, such as using the gradient magnitude for boundary location and statistical, occlusion, or size metrics. In this paper, we present a novel transfer function method which can provide more specificity for data classification by combining different transfer function spaces. In this work, a 2D transfer function can be combined with 1D transfer functions which improve the classification. Specifically, we use the traditional 2D scalar/gradient magnitude, 2D statistical, and 2D occlusion spectrum transfer functions and combine these with occlusion and/or size-based transfer functions to provide better specificity. We demonstrate the usefulness of the new method by comparing to the following previous techniques: 2D gradient magnitude, 2D occlusion spectrum, 2D statistical transfer functions and 2D size based transfer functions.
It is well known that people movement exhibits a high degree of repetition since people visit regular places and make regular contacts for their daily activities. This paper 1 1 This work is supported by Boeing Trusted Software Center at the Information Trust Institute, University of Illinois. presents a novel framework named Jyotish, 2 2 In Sanskrit, Jyotish (Ji-o-tish) is the person who predicts future events. which constructs a predictive model by exploiting the regularity of people movement found in the real joint Wifi/Bluetooth trace. The constructed model is able to answer three fundamental questions: (1) where the person will stay, (2) how long she will stay at the location, and (3) who she will meet. In order to construct the predictive model, Jyotish includes an efficient clustering algorithm to cluster Wifi access point information in the Wifi trace into locations. Then, we construct a Naive Bayesian classifier to assign these locations to records in the Bluetooth trace and obtain a fine granularity of people movement. Next, the fine grain movement trace is used to construct the predictive model including location predictor, stay duration predictor, and contact predictor to provide answers for three questions above. Finally, we evaluate the constructed predictive model over the real Wifi/Bluetooth trace collected by 50 participants in University of Illinois campus from March to August 2010. Evaluation results show that Jyotish successfully constructs a predictive model, which provides a considerably high prediction accuracy of people movement.
The effect of tensile stretching on pure PEO and P(EO) x LiCF3SO3 (x =10 and 20) films was studied using polarized FTIR spectroscopy, wide angle scattering X-ray scattering (WAXS) and small angle X-ray scattering (SAXS). The polarization effects observed in the spectra are readily explained by the selection rules governing IR transitions and symmetry-based vibrational mode assignments of PEO and the 3:1 compound, P(EO)3LiTf. The degree of polymer chain orientation in the stretched samples as measured by the average of the second Legendre polynomial was calculated from the dichroic ratio for the PEO helices in both pure PEO and the 20:1 film. The degree of chain orientation was markedly higher in the 20:1 film than in the pure PEO film; however it was difficult to calculate the degree of orientation in the 10:1 film. The addition of LiTf causes a slight increase in the fractional crystallinity of the samples as determined from the WAXS data. Orientation of the films did not significantly affect the fractional crystallinity for the 10:1 and 20:1 samples, whereas a slight decrease in the fractional crystallinity was noted for pure PEO upon stretching. The SAXS data suggested that the average crystal size becomes smaller with the addition of lithium triflate to PEO. The SAXS data also indicated that substantial morphological changes occur upon stretching, since the Bragg peak due to the crystalline–amorphous phase separation disappeared upon stretching. These data, taken together, suggest that in the 10:1 film, the tensile stress tends to form small, unoriented domains of the 3:1 compound.
Li2MnSiO4/C nanocomposites have been successfully prepared by a two-step method to accurately control the formation of the orthorhombic Pmnb phase, and phosphate substitution is used to improve the electrochemical performance of this cathode material. The structure and electrochemical properties are investigated using X-ray diffraction, scanning electron microscope and electrochemical tests. The crystal structure of this material is confirmed to be Pmnb polymorph and the average grain size is about 80–100nm. The electrochemical tests indicate that Li2.1Mn0.9[PO4]0.1[SiO4]0.9/C nanocomposites deliver a discharge specific capacity of 216.9mAh·g−1 after initial activation and it shows much enhanced electrochemical performance compared with Li2MnSiO4/C nanocomposites. Furthermore, the XRD patterns, HRTEM images and Raman analysis reveal the crystal structural changes of the two samples during cycling. Thus, this material has shown potential for high power applications in Li-ion batteries.
Thin films of nanocomposites between carbon nanotubes (CNTs) and three different hexacyanometallates (HCMs) – Prussian blue, ruthenium purple (RP) and cobalt hexacyanoferrate (CoHCFe) - were synthesized with different cations: K+, Na+ and Li+. The effect of the cations in both the structure and properties of the HCMs was evaluated by several characterization techniques, showing that the nature of the cation is directly related to the size of the channels in the produced HCM structure, as well as to the defect content, the electrochemical behavior, the electrochemical stability and the strength of the interaction between the HCM and the CNTs. Due to the large hydrated radius, Li+ produced the more defective and less stable HCMs, while the HCM synthesized with Na+ had large porous and organized structure. All those factors deeply affect the performance of the different films when applied as cathodes for aqueous potassium-, sodium- and lithium-ion secondary battery, which depends on the relationship between the size of hydrated ion and the lattice of the HCM structure. The discharge profile and capacity for RP is reported by the first time. CoHCFe-based composites achieved capacities up to 150 mAh g−1 at 0.67 A g−1 rate, with retention of 90% after 2000 cycles.
This paper presents a study about an off-grid (stand-alone) photovoltaic (PV) system for electrification of a single residential household in the city of Faisalabad, Pakistan (31.42°N, 73.08°E, 184m). The system has been designed keeping in view the required household load and energy available from the sun. The complete model for the sizing of complete PV system has been presented to determine the required PV power rating, battery storage capacity, size of charge controller and inverter to fulfill the required load. Using this model, the peak power and area of PV modules, capacity of battery backup, size of charge controller and inverter was calculated to be 1928Wp and 12.85m2, 9640.5Wh, 56.65A and 1020W, respectively. The economics evaluation using life cycle cost (LCC) analysis of the complete system has also been carried out. The LCC of the system was found to be PKR. 457,306 whereas the annualized life cycle cost (ALCC) was determined to be PKR. 31,963yr−1, respectively. The unit electricity cost has also been calculated and was found to be PKR. 14.8kWh−1. The results show that unit cost of electricity produced using off-grid PV system is lower than the unit cost charged in case of conventional electric supply to the residential areas. It is concluded that off-PV electricity is technically and economically viable technology for the electrification of residential applications.
We calculated stem CO2 efflux (ES) of Pinus canariensis at a timberline site in Tenerife, Canary Islands, from March 7, 2008 and February 9, 2009. ES varied markedly throughout the year. Although ES generally followed the seasonal trends in temperature, we observed seasonal adjustment of ES in both ES normalized to temperature (ES10) and the temperature sensitivity (Q10) resulting in lower ES10 values during the warm and dry season as compared during the cold and wet season; the latter corresponding with the period of stem growth. The Q10 by contrast, was higher during the warm and dry summer than during the cold and wet season, an observation suggesting that climate extremes such as summer drought in the Mediterranean may override the observation that Q10 declines with increasing temperature. As concurrent measurements estimating the potential impact of sap flow on ES revealed no interaction in P. canariensis, the Q10 values were used along with ES10 and stem temperature records to predict annual total ES and for partitioning total ES into its maintenance (Em) and a growth (Eg) component.
Genetic variation may partially underlie complex personality and physiological traits—such as impulsivity, risk taking and stress responsivity—as well as a substantial proportion of vulnerability to addictive diseases. Furthermore, personality and physiological traits themselves may differentially affect the various stages of addiction, defined chronologically as initiation of drug use, regular drug use, addiction/dependence and potentially relapse. Here we focus on recent approaches to the study of genetic variation in these personality and physiological traits, and their influence on and interaction with addictive diseases.
Nitrogen-doped carbon coated Li4Ti5O12 (NC–LTO) nanocomposite as an anode material for lithium-ion batteries (LIBs) is prepared with acetyl glucosamine as carbon source by pre-coating process combined with ball milling. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy are used to characterize the NC–LTO materials. The results show that NC–LTO samples exhibit the obvious improvements in rate capability and cycling performance compared with the LTO samples coated by carbon (C–LTO) derived from sugar and pure LTO samples. The carbon pre-coating process could significantly decrease the agglomeration of TiO2 precursors and the uniformly coated nitrogen-doped carbon increase the interfacial stability and electric conductivity of LTO. At the charge–discharge rate of 0.2 C, 5.0 C and 10.0 C and 20.0 C, the discharge capacities of NC–LTO samples are 167.4, 146.3, 133.4 and 128.2 mAh g−1, respectively. After 1000 cycles at 1 C, its capacity retention is 95.9% with nearly ignored capacity fading.
In order to void environmental pollution and an energy shortage, the application of clean and renewable energy, such as solar, instead of fossil fuel is foreseen as a prospective issue. It is urgent and important to develop and optimize various energy storage and conversion technologies and materials aimed at utilization of different clean energy sources. Metal–organic frameworks (MOFs), a new class of porous crystalline materials, act as an outstanding candidate in this field based on their high surface areas, controllable structures and excellent electrochemical properties. Here, selected recent and significant advances in the development of MOFs for clean energy applications are reviewed, and special emphases are shown to the applications of MOFs as platforms for hydrogen production and storage, fuel cells, Li-ion rechargeable batteries, supercapacitors and solar cells.
Solar energy offers a viable solution to our growing energy need. While adoption of conventional photovoltaics on rooftops and in solar farms has grown rapidly in the last decade, there is still plenty of opportunity for expansion. See-through solar technologies with partial light transmission developed over the past 30 years have initiated methods of integration not possible with conventional modules. The large-scale deployment necessary to offset global energy consumption could be further accelerated by developing fully invisible solar cells that selectively absorb ultraviolet and near-infrared light, allowing many of the surfaces of our built environment to be turned into solar harvesting arrays without impacting the function or aesthetics. Here, we review recent advances in photovoltaics with varying degrees of visible light transparency. We discuss the figures of merit necessary to characterize transparent photovoltaics, and outline the requirements to enable their widespread adoption in buildings, windows, electronic device displays, and automobiles.
Policy makers from around the world are trying to emulate successful innovation systems in order to support economic growth. At the same time, innovation governance systems are being put in place to ensure a better integration of stakeholder views into the research and development process. In Europe, one of the most prominent and newly emerging governance frameworks is called Responsible Research and Innovation (RRI). This article aims to substantiate the following points: (1) The concept of RRI and the concept of justice can be used to derive similar ethical positions on the nano-divide. (2) Given the ambitious policy aims of RRI (e.g. economic competitiveness enhancer), the concept may be better suited to push for ethical outcomes on access to nanotechnology and its products rather than debates based on justice issues alone. It may thus serve as a mediator concept between those who push solely for competitiveness considerations and those who push solely for justice considerations in nano-technology debates. (3) The descriptive, non-normative Systems of Innovation approaches (see below) should be linked into RRI debates to provide more evidence on whether the approach advocated to achieve responsible and ethical governance of research and innovation (R&I) can indeed deliver on competitiveness (in nano-technology and other fields).
Gelled electrolytes prepared from fumed silica for use in absorptive glass mat valve-regulated lead-acid (AGM VRLA) batteries and the effect of veratraldehyde addition on the electrochemical behavior and performance of AGM VRLA batteries are investigated. Cyclic voltammetry is used to investigate differences in the electrochemical behaviors of nongelled and gelled electrolytes and between gelled electrolytes with and without veratraldehyde. Battery performance is tested under 100% depth of discharge (100% DoD) conditions at both low- (0.1C) and high- (1C) rate discharges. The addition of silica or veratraldehyde does not affect the main reaction of the lead-acid batteries but tends to suppress the hydrogen evolution reaction. AGM VRLA batteries with gelled electrolytes have a higher discharge capacity and longer cycle life than the conventional nongel AGM VRLA batteries. The addition of 0.005% (w/v) veratraldehyde further improves battery performance, but higher (0.01%, w/v) veratraldehyde concentrations reduce it and correlate with the enhanced growth of lead sulfate crystals. The AGM VRLA battery prepared from a gelled electrolyte containing 0.005% (w/v) veratraldehyde provides the best battery performance in every operating temperature studied (0–60°C).
To design an inexpensive, non-toxic, practical replacement to the internal combustion engine, significant advances in battery technology are required. Germanium anodes offer more than four times larger capacity than presently used graphite anodes. Yet large volume changes during operation severely limit their lifetime. To understand the origin, dynamics, and failure mechanisms of these and other electrode materials, it is essential to image batteries under operating conditions. Using transmission X-ray microscopy the morphology and electron density changes in Ge anode particles are tracked during operation. We observe significant size dependence on the cycling characteristics of Ge particles. Only Ge particles with diameters larger than a few microns display cracks during cycling. Small Ge particles experience volume expansion and cracking before their larger counterparts, but rapidly lose electrical contact. With in situ nanotomography, we demonstrate unambiguously for the first time the fracturing of alloying anode materials into completely unconnected pieces. Moreover, we show that the density changes due to lithiation are consistent with partial transformation into a Li15Ge4-like phase. Our results demonstrate the significant value in linking electrochemical performance studies with morphological evolution to understand failure mechanisms and encourage more systematic searches for a viable high capacity anode material.
Developing rechargeable sodium ion batteries with high capacity and long cycle life is still a big challenge. Herein, we present P2-type concentration-gradient material with average composition of Na0.67Ni0.167Co0.167Mn0.67O2, which exhibits relatively high discharge capacity and excellent stability. The material delivers higher discharge capacity and better rate performance than that of the concentration-constant Na0.67Ni0.167Co0.167Mn0.67O2 during cycling. Also, the material exhibits excellent capacity retention of ∼87% after 100 cycles. The high discharge capacity is attributed to the Ni-rich core and the improvement in cycling stability is due to a gradual and continuous increase of Mn4+ in the concentration-gradient spherical particles. The primary particles on the Mn-rich surface have smaller size than that of the constant-concentration samples, leading to a preferential crystalline state, therefore they can facilitate excellent transport properties for Na ions insertion/extraction process. The P2-type concentration-gradient material provides a new way for the development of advanced sodium ion batteries with high capacity and long cycle life.