batterydata/paper-abstracts huggingface dataset:
Transition metal oxides (TMOs) have drawn great attention in applications towards negative electrodes for lithium-ion batteries (LIBs). TMOs undergo conversion reactions upon discharge/charge process, which involves volume changes that cause pulverization and further result in poor cycling performances. Thus, it is important to engineer the microstructure of TMOs to accommodate the volume expansion/contraction during discharge/charge process and to improve the charge-transfer process. Herein, we report nanostructured CuO nanoflake arrays with a highly open microstructure on a nanoporous Cu substrate as binder-free negative electordes for LIBs. Nanoporous Cu substrate was obtained by dealloying process. By oxidizing one single side of a nanoporous Cu substrate under mild conditions, the 2D self-supported CuO nanoflake arrays were fabricated and can provide fast ion diffusion paths and accommodate large volume changes in the process of discharge/charge. Due to the synergistic effects of the highly conductive substrate and the intrinsically stable microstructure, the as-prepared CuO electrodes deliver a high capacity with stable performance of ∼100% capacity retention (∼800 mAh·g−1) after 120 cycles, and good rate performances up to 10 C. Considering the enhanced charge-transfer process, notable structural stability, and low-cost fabrication, the as-prepared CuO negative electrodes hold great promise for advanced LIBs.
Hierarchical porous carbon derived from lignin (denoted as LHPC) was prepared via a facile method. In this method, KOH acts both as activating agent and template. The obtained LHPC was composed of unique 3D macroporous network with mesopores and micropores decorated on carbon walls. LHPC was further applied as the anode material of lithium ion battery and displayed a stable, high capacity of 470mAhg−1 after 400 galvanostatic charge-discharge cycles at a current density of 200mAg−1. Furthermore, LHPC displayed high cycling stability and perfect rate capability. This facile method for the preparation of LHPC offers a new route for the preparation of a series of hierarchical porous carbons for the application in supercapacitors, fuel cells, lithium ion batteries, etc.
The goal of the present study was to investigate whether spontaneous functional recovery following insult to the language-dominant hemisphere continues in the so-called “chronic stage,” and if so, to examine its neuro-functional correlates. We used a longitudinal functional magnetic resonance imaging (fMRI) block design, where each young patient served as his/her own control. Specifically, we examined whether language functions differed significantly in two monitoring sessions conducted years apart, both in the chronic stage, where almost no functional changes are expected. We focused on a unique cohort of young brain damaged patients with aphasiogenic lesions occurring after normal language acquisition, in order to maximize the potential of plasticity for language reorganization following brain damage. The most striking finding was that the linguistic recovery of our patients was significant not just relative to their linguistic scores on initial testing (T1), but also in absolute terms, relative to the respective age-matched normal population. Such improvement, therefore, cannot be simply attributed to the natural process of development. Overall, we found that right hemisphere (RH) activation was associated with better recovery in the chronic stage. Our longitudinal findings may challenge the view of recovery as ending within the first year following onset, suggesting that the RH may provide the substrate for ongoing plasticity in the damaged brain.
Polyacrylonitrile (PAN)-based carbon felts with different fibre properties were studied in terms of their suitability as porous flow-through electrode materials in all vanadium redox flow batteries. The crystallinity and their bulk hetero element content (in particular nitrogen) of the carbon fibres was shown to produce a significant effect on the electrocatalytical properties of the electrodes towards vanadium species. Similar effects were seen on the capacity losses associated with concomitant hydrogen evolution. Adjustments of fibre properties offer the potential of manufacturing improved electrode materials, potentially without additional steps such as surface activation or decoration with catalytically active species.
A novel ultrafine leady oxide has been prepared from a combustion–calcination process of lead citrate precursor (Pb3(C6H5O7)2·3H2O), by hydrometallurgical leaching of spent lead pastes firstly. The leady oxides are used to assemble lead acid battery which are subjected to cyclic voltammetry (CV) and battery testing. Various key properties of the new oxides, such as morphology, crystalline phases, degree of oxidation, apparent density and water and acid absorption value have been characterized by chemical analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that leady oxides synthesized at different calcination temperatures mainly comprise β-PbO, α-PbO and Pb. Unlike traditional leady oxide, the new oxide product prepared at 375 °C has a rod-like morphology with greater porous structure, and appears smaller density, lower value of acid absorption and larger propensity for water absorption. In battery testing, the 20 h rate and 1C rate discharge time have exceeded 26 h and 40 min, respectively. Results reveal that the leady oxide prepared at 375 °C exhibits excellent electrochemical performance and initial capacity as positive active material. While leady oxide obtained at 450 °C presents a relatively improved cycle life. Further work is to optimize the battery manufacturing process for better cycle performance.
Non-aqueous Li–air-batteries can provide potentially a very high energy density. The reaction at the positive electrode is the oxygen reduction reaction. Its products are lithium oxides (mainly Li2O2) that deposit as solid compound in the porous gas diffusion electrode (GDE). This can cause passivation of the electrode surface or clogging of gas diffusion pathway though the porous material. Here a new method is reported to measure in-situ the oxygen permeation though a GDE during the discharge process. It is based on the concepts of scanning electrochemical microscopy (SECM) in which a positionable microelectrode (ME) is used to detect the influx of oxygen in an deaerated electrolyte close to the outer surface of the GDE. However, no steady-state current for oxygen reduction at the ME can be obtained in Li-containing electrolytes because solid lithium oxides also deposit on the ME. Therefore, a pulsed potential program was developed that periodically removes deposits from the surface of the ME and eliminates the effect of surface passivation of the probe electrode. We validated this method by monitoring the oxygen reduction current at the ME as a result of oxygen permeating GDEs of different thickness.
Thermal management and energy crisis have been two major problems in this 21st century. The thermoelectric concept is seen as a perfect solution for the both issues provided its figure of merit is large enough to compete with the traditional techniques. Since the use of semiconductor materials for thermoelectric applications, there has been a huge quest for improving its figure of merits (ZT) to cross 3 in order to make it commercially viable. This review starts with thermoelectric concepts and explains briefly the challenges in enhancing the figure of merits. It also reports the various approaches adopted in bulk materials, complex structures and the recent nanostructures to circumvent the interdependency of parameters in achieving higher ZT. It ends with discussion of the future trends of nanocomposite materials and its underlying challenges of fabrication.
The novel ultrathin pre-lithiated V6O13 nanosheets are prepared through a low-temperature exfoliation in argon followed by a secondary hydrothermal lithiation. The smallest electrochemical devices based on nanosheet cathodes are fabricated to in situ probe the intrinsic advantages of pre-lithiated nanosheets. Pre-lithiated nanosheets show one order of magnitude higher in electrical conductivity compared with non-lithiated nanosheets. The conductance of ultrathin pre-lithiated V6O13 nanosheets still remains at the same level after discharge process while that of ultrathin non-lithiated nanosheets decreases over two orders of magnitude. The electrochemical performances of nanosheet cathodes before and after pre-lithiation are compared to further demonstrate the enhancement of the pre-lithiation. Ultrathin pre-lithiated V6O13 nanosheet cathodes exhibit a high discharge capacity of 301 mAh g−1 at the current density of 100 mA g−1. At a higher current density of 1000 mA g−1, the capacity retention after 150 cycles of ultrathin V6O13 nanosheet cathodes is greatly improved from 46% to 98% after pre-lithiation. The enhanced electrical conductance, excellent discharge capacities and cycling performance demonstrate the great potential of ultrathin pre-lithiated V6O13 nanosheets in next-generation high-performance energy storage applications.
A detailed analysis of the capacity fade of a battery/supercapacitor hybrid and a battery alone has been carried out at 55 °C by discharging them at three different pulse rates. The applied peak current amplitudes were 5C (7 A), 3C (4.2 A), and 1C (1.4 A), respectively. The results indicated that for hybrids the pulse discharge run time was extended for all pulse discharge rates. The ohmic resistances estimated as a function of the pulse discharge rates were smaller for hybrids when compared with those for batteries. The variation of the ohmic resistance under pulse discharge with cycling, irrespective of the pulse discharge rate was smaller for hybrids than that for the batteries. The batteries and hybrids cycled at the lowest pulse discharge rate (high pulse discharge time) have larger capacity fade when compared with the capacity fade of the batteries and the hybrids discharged using higher discharge rates (low pulse discharge time). Impedance, cyclic voltammogram, and the rate capability studies were carried out on batteries cycled alone and on batteries cycled as part of the hybrid. The battery showed larger increase in the interfacial impedance with cycling when compared with the hybrid system.
As the importance of applications depending on electrical energy storage devices (EESDs), including portable electronics, electric vehicles, and devices for renewable energy storage, has gradually increased, research has focused more and more on innovative energy systems for advanced EESDs in order to achieve enhanced performance. Over the past two decades, graphene-based materials have been considered as ideal electrode materials for lithium-ion, sodium-ion, and lithium/sulfur batteries, as well as supercapacitors, due to their promising applications for advanced electrodes. In this review, we will demonstrate the issues and challenges of each type of EESD, with an emphasis placed on the use of graphene-based electrodes. Recent trends related to research into graphene-based composite materials as electrodes in Korea will also be shown and a summary of the overall strategies and future perspectives will be given.
Fast charging stations are vital components for public acceptance of electric vehicle (EV). The stations are connected to the electric grid and can recharge an electric vehicle in less than 20min. Charging station development is highly influenced by the government policy in allocating station development costs. This paper presents a Mixed-Integer Non-Linear (MINLP) optimization approach for optimal placing and sizing of the fast charging stations. The station development cost, EV energy loss, electric gird loss as well as the location of electric substations and urban roads are among the factors included in the proposed approach. Geographic information has been used to determine EV energy loss and station electrification cost. The optimization problem is solved using genetic algorithm technique. Application of the proposed approach to analyze the impact of different station development policies has been discussed. The impact of electric grid reliability on charging station place and size has been evaluated using a proposed index to evaluate loss of charging cost. Results showed the robustness and efficacy of the proposed method to determine optimal place and size of the charging stations.
This article describes the approach to computing the version of the stochastic growth model with idiosyncratic and aggregate risk that relies on collapsing the aggregate state space down to a small number of moments used to forecast future prices. One innovation relative to most of the literature is the use of a non-stochastic simulation routine.
Particle signals are detected by two parallel measuring chains which consist of a detector and analog to digital converter. We have used OPT101 as photodiode and ADS7870 for A/D converter and the output signal from two parallel measuring chains is processed by on line correlation filter. This filter works as real time systems. A correlation algorithm has been applied for this work. The signal to noise ratio has been increased by applying correlation filter. The gain of the filter has been improved by introducing digital signal processing.
Fossil fuels possess very useful properties not shared by non-conventional energy sources that have made them popular during the last century but unfortunately they are not renewable. Since the oil crisis of 1973, considerable progress has been made in the search for alternative energy sources. Among the candidates, hydrogen holds a pre-eminent position because of its high energy content, environmental compatibility and ease of storage and distribution. Hydrogen can be produced in a variety of ways. Water electrolysis is one of the most utilized industrial processes for hydrogen production. This article discusses advantages and disadvantages of hydrogen energy. Besides, barriers and challenges to hydrogen economy have been summarized. The current energy situation in Pakistan is presented followed by a road map to hydrogen economy in Pakistan. It is concluded that a combination of fuel cells and a hydrogen infrastructure is a way forward to combat the long-term challenges of climate change and energy security for Pakistan. The hydrogen economy potentially offers the possibility to deliver a range of benefits for the country; however, significant challenges exist and these are unlikely to be overcome without serious efforts.
The paper uses household economic panel data from five countries—Australia, Britain, Germany, Hungary and The Netherlands—to provide a reassessment of the impact of economic well-being on happiness. The main conclusion is that happiness is considerably more affected by economic circumstances than previously believed. In all five countries wealth affects life satisfaction more than income. In the countries for which consumption data are available (Britain and Hungary), non-durable consumption expenditures also prove at least as important to happiness as income.
The present work integrates the active biomonitoring (ABM) concept in mussels Mytilus galloprovincialis from the South coast of Portugal transplanted during 28 days between two sites with different sources of contamination, and vice versa, in order to assess biological effects in these mussels. For that purpose a multibiomarker approach was used. The suit of biomarkers indicative of metal contamination were metallothioneins (MT) and the enzyme δ-aminolevulinic acid dehydratase (ALAD), for organic contamination mixed function oxidase system (MFO), glutathione-S-transferase (GST) and acetylcholinesterase (AChE), as oxidative stress biomarkers superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lipid peroxidation (LPO). These biomarkers were used to determine an index to evaluate the stress levels in these two sites. Site A is strongly influenced by metallic contamination, with higher Cu, Cr and Pb in M. galloprovinciallis, as well as higher MT levels, antioxidant enzymes activities and LPO concentrations, and lower ALAD activity. In site B organic compounds (PAHs) are prevalent and native mussels show higher activities of the MFO system components and GST. Transplanted mussels had significant alterations in some biomarkers that reflect the type of contaminants present in each site, which demonstrates the primary role of the environment in determining the physiological characteristics of resident mussels. Therefore the application of ABM using a battery of biomarkers turns out to be a useful approach in sites where usually complex mixtures of contaminants occurs. In this study the biomarkers that better differentiate the impact of different contaminants at each site were MT, CYP450, SOD and CAT.
Thin amorphous manganese oxide layers with a thickness of 3–5nm are electrodeposited on a carbon nanotube (CNT) film substrate that has a three-dimensional nanoporous structure (denoted as MnO2/CNT electrode). For the purpose of comparison, manganese oxide films are also electrodeposited on a flat Pt-coated Si wafer substrate (denoted as MnO2 film electrode). The pseudocapacitive properties of the MnO2 film and MnO2/CNT electrodes are examined in both aqueous electrolyte (1.0M KCl) and non-aqueous organic electrolyte (1.0M LiClO4 in propylene carbonate). While both types of electrode show pseudocapacitive behaviour in the aqueous electrolyte, only the MnO2/CNT electrode does so in the organic electrolyte, due to its high oxide/electrolyte interfacial area and improved electron conduction through the CNT substrate. Compared with the MnO2 film electrode, the MnO2/CNT electrode shows a much higher specific capacitance and better high-rate capability, regardless of the electrolyte used. Use of the organic electrolyte results in a ∼6 times higher specific energy compared with that obtained with the aqueous electrolyte, while maintaining a similar specific power. The construction of a three-dimensional nanoporous network structure consisting of a thin oxide layer on a CNT film substrate at the nm scale and the use of an organic electrolyte are promising approaches to improving the specific energy of supercapacitors.
Electrospinning has been employed to fabricate carbonaceous materials with larger surface areas for vanadium redox flow batteries. However, the woven carbon nanofibers prepared with conventional electrospinning methods are plagued by the low porosity and poor permeability, thereby causing a significant mass-transport resistance during the operation of batteries. To tackle this problem, we report a novel method by self-assembling porous carbon fibers into large bundles to form electrodes. This electrode is fabricated by electrospinning polyacrylonitrile and polystyrene binary solutions. Instead of forming single fibers, the individual fibers are self-assembled into fiber bundles by properly managing the viscosity of the precursor solution. The formation of large fiber bundles significantly enlarges the pore size while retaining large specific surface areas. The single cell with the as-prepared electrodes achieves an energy efficiency of 87.7% at a current density of 100 mA cm−2, which is 15.2% higher than that of the single cell with conventional electrospinning electrodes. The energy efficiency still maintains over 80% at 200 mA cm−2. More importantly, the discharge capacity and electrolyte utilization are nearly doubled. All these results demonstrate that this electrode preparation method is effective to improve the mass transport properties of traditional electrospun electrodes in vanadium redox flow batteries.
Various hybrid polymers composed of oligo(ethylene oxide) unit and butyrolactone unit, such as polymer blend, block copolymer and random copolymer, were synthesized by radical polymerization of poly(ethylene oxide) methyl ether methacrylate (PEOMA) and/or α-methylene-γ-butyrolactone (MBL), and the ionic conductivities and thermal properties of the solid polymer electrolytes using those hybrid polymers and LiN(SO2CF3)2 were investigated. The solid polymer electrolyte using homopolymer of PEOMA (poly(PEOMA)) showed higher ionic conductivity and larger temperature dependence of ionic conductivity than those of the solid polymer electrolyte using homopolymer of MBL (poly(MBL)). The ionic conductivities of the solid hybrid polymer electrolytes were improved at especially low temperature region compared with each homopolymer electrolyte. This result indicates that the decline in the ionic conductivity at low temperature, which is characteristic of PEOMA unit, has been effectively reduced by combining with MBL unit. The poly(PEOMA) and the block or random copolymer electrolytes showed the higher thermal stability than the poly(MBL) and the polymer blend electrolytes.
In 1990, the Space Department of the Defence Evaluation and Research Agency (DERA) initiated the Space Technology Research Vehicle (STRV) programme. The aim was to design, build, test and launch a relatively low-cost satellite weighing only 50kg and carrying a variety of experimental payloads derived primarily from MoD-sponsored research within the Department. What is the status of this programme 10 years later?
Lithium-air batteries using hydrophobic ionic liquid consisting of 1-alkyl-3-methyl imidazolium cation and perfluoroalkylsulfonyl imide anion were investigated. 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, which has high conductivity and prevents hydrolysis of the lithium anode, showed the best electrolyte performance. The cell worked for 56 days in air, and the cathode carbon materials showed high discharge capacity of 5360mAhg−1. In addition to hydrophobic ionic liquids for use as electrolytes, various carbon materials for use as high-capacity cathodes were investigated.
PV installations in buildings can utilize different on-site flexibility resources to balance mismatch in electricity production and demand. This paper studies cost-optimal and rule-based control for buildings with PV, employing a heat pump, thermal and electrical storage and shiftable loads as flexibility sources to increase the value of PV for the prosumer. The cost-optimal control minimizes variable electricity cost employing market data on electricity price and optionally constrains grid feed-in to zero; the rule-based control aims at maximizing PV self-consumption. The flexibility strategies are combined into a simulation model to analyze different system configurations over a full year. The applicability of the new model is demonstrated with a case study with empirical data from a real low-energy house in Southern Finland. Compared to inflexible reference control with a constant price for bought electricity, cost-optimal control employing hourly market price of electricity achieved 13–25% savings in the yearly electricity bill. Moreover, 8–88% decrease in electricity fed into the grid was obtained. The exact values depend on PV capacity and the flexibility options chosen. Limiting grid feed-in to zero led to less energy efficient control. The most effective flexibility measures in this case turned out to be thermal storage with a heat pump and a battery, whereas shiftable appliances showed only a marginal effect.