batterydata/paper-abstracts huggingface dataset:
We analyze shifts in the structure of China’s capital outflows over the past decade. The composition of gross outflows has shifted from accumulation of foreign exchange reserves by the central bank to non-official outflows. Unlocking the enormous pool of domestic savings could have a significant impact on global financial markets as China continues to open up its capital account and as domestic investors look abroad for returns and diversification. We analyze in detail the allocation patterns of Chinese institutional investors (IIs), which constitute the main channel for foreign portfolio investment outflows. We find that, relative to benchmarks based on market capitalization, Chinese IIs underweight developed countries and high-tech sectors, respectively, in their international portfolio allocations but overinvest in high-tech stocks in developed countries. To further examine Chinese IIs’ joint decisions on destination country–sector pairs, we construct continuous measures of revealed comparative advantage and disadvantage in a sector for a country based on trade patterns. We find that, in their foreign portfolio allocations, Chinese IIs overweight sectors in which China has a comparative disadvantage. Moreover, Chinese IIs concentrate such investments in countries that have higher comparative advantage in those sectors. Diversification and information advantages related to foreign imports to China seem to influence patterns of foreign portfolio allocations, while yield-seeking and learning motives do not.
Heteroatom doped carbon materials represent one of the most prominent families of materials that are used in energy related applications, such as fuel cells, batteries, hydrogen storage or supercapacitors. While doping carbons with nitrogen atoms has experienced great progress throughout the past decades and yielded promising material concepts, also other doping candidates have gained the researchers' interest in the last few years. Boron is already relatively widely studied, and as its electronic situation is contrary to the one of nitrogen, codoping carbons with both heteroatoms can probably create synergistic effects. Sulphur and phosphorus have just recently entered the world of carbon synthesis, but already the first studies published prove their potential, especially as electrocatalysts in the cathodic compartment of fuel cells. Due to their size and their electronegativity being lower than those of carbon, structural distortions and changes of the charge densities are induced in the carbon materials. This article is to give a state of the art update on the most recent developments concerning the advanced heteroatom doping of carbon that goes beyond nitrogen. Doped carbon materials and their applications in energy devices are discussed with respect to their boron-, sulphur- and phosphorus-doping.
Spinel metal oxide nanoparticles are promising alternative anode materials for Li-ion batteries showing enhanced cycling performances and specific theoretical capacity resulting from a combination of alloying and conversion reactions during dis-/charge. In this work, we study the effect of the initial lithium insertion into carbon-coated ZnFe2O4 anodes by X-ray absorption spectroscopy. We are able to closely monitor the structural changes and the electronic structure in-situ and in-operando. For low lithium uptake (up to 0.3 Li + per formula unit) the initial crystalline structure is not significantly modified. Further lithium insertion causes the migration of Zn atoms from tetrahedral 8a sites into vacant octahedral 16c sites, and Fe is gradually reduced from Fe 3 + to Fe 2 + upon lithium insertion. In the early stage of lithiation (up to 2 Li + per formula unit) we find no evidence of Zn reduction. Also, a gradual damping of EXAFS signals, linked to the increasing structural disorder, is observed.
Understanding the behavior of soluble intermediate lithium polysulfide species is vitally important for improving the electrochemical performances of lithium-sulfur batteries. Herein we explore a simple in-operando lithium-sulfur cell design to enable direct visualization of the formation of the soluble polysulfide species and their temporal and spatial distribution over the entire discharge/charge cycle under an optical microscope. Our results reveal detailed evidence of electrochemical degradation in lithium-sulfur batteries and help us to understand the improvements in electrochemical performances using advanced lithium-sulfur cell designs. As examples, we show that a cathode consisting of hollow sulfur nanoparticles with a conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) coating exhibits significantly reduced dissolution of polysulfides into the electrolyte, and thus superior electrochemical performance could be achieved. Moreover, the trapping of soluble polysulfide species in the cathode side was also confirmed in our designed in-operando lithium-sulfur cell with a Nafion modified separator.
Oxidative stress is closely related to the pathogenesis of neurodegenerative disorders such as Parkinson’s disease. Carvedilol, a nonselective β-adrenergic receptor blocker with pleiotropic activity has been shown to exert neuroprotective effect due to its antioxidant property. However, the neuroprotective mechanism of carvedilol is still not fully uncovered. The phosphotidylinositol 3-kinase (PI3K)/Akt signaling pathway plays key role in cell survival and the nuclear factor erythroid 2–related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway is the major cellular defense mechanism against oxidative stress. Here we investigated the effects of carvedilol on 6-hydroxydopamine (6-OHDA)-induced cell death as well as the Akt and Nrf2/ARE pathways in PC12 cells. We found that carvedilol significantly increased cell viability and decreased reactive oxygen species in PC12 cells exposed to 6-OHDA. Furthermore, carvedilol activated the Akt and Nrf2/ARE pathways in a concentration-dependent manner, and increased the protein levels of heme oxygenase-1(HO-1) and NAD(P)H quinone oxidoreductase-1(NQO-1), two downstream factors of the Nrf2/ARE pathway. In summary, our results indicate that carvedilol protects PC12 cells against 6-OHDA-induced neurotoxicity possibly through activating the Akt and Nrf2/ARE signaling pathways.
A new aqueous rechargeable battery combining an intercalation cathode with a metal (first order electrode) anode has been developed. The concept is demonstrated using LiMn2O4 and zinc metal electrodes in an aqueous electrolyte containing two electrochemically active ions (Li+ and Zn2+). The battery operates at about 2 V and preliminarily tests show excellent cycling performance, with about 90% initial capacity retention over 1000 charge–discharge cycles. Use of cation-doped LiMn2O4 cathode further improves the cyclability of the system, which reaches 95% capacity retention after 4000 cycles. The energy density for a prototype battery, estimated at 50–80 Wh kg−1, is comparable or superior to commercial 2 V rechargeable batteries. The combined performance attributes of this new rechargeable aqueous battery indicate that it constitutes a viable alternative to commercial lead-acid system and for large scale energy storage application.
Microbatteries with nanoscale features were made. Alumina filtration membranes having pores 200nm in diameter served as the “jackets” to hold a PEO–lithium triflate electrolyte. Graphite particles approximately 75μm in diameter were placed on the membrane covering numerous electrolyte-filled pores. The bottom of the pores were filled with V2O5 xerogel making cathode structures having a circular surface area with a diameter of 200nm. In some cases, the V2O5 xerogel was filled with 35% carbon nanotubes making a nanocomposite cathode material that exhibited better performance. In effect, microbatteries of numerous parallel nanocells were made. These microbatteries were charged and discharged and, though they had low capacities ranging from 3 to 18mAh/g, it was shown that these small lithium batteries could function in a viable manner.
A nanocrystalline Li4Ti5O12–TiO2 duplex phase has been synthesized by a simple basic molten salt process (BMSP) using an eutectic mixture of LiNO3–LiOH–Li2O2 at 400–500°C. The microstructure and morphology of the Li4Ti5O12–TiO2 product are characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The sample prepared by heat-treating at 300°C for 3h (S-1) reveals dense agglomerates of ultra-fine nanocrystalline Li4Ti5O12; with heat treatment at 400°C for 3h (S-2), there is a duplex crystallite size (fine<10nm, and coarse>20nm) of Li4Ti5O12–TiO2; at 500°C for 3h (S-3), a much coarser and less-dense distribution of lithium titanate (crystallite size ∼15–30nm) is observed. According to the results of electrochemical testing, the S-2 sample shows initial discharge capacities of 193mAhg−1 at 0.2C, 168mAhg−1 at 0.5C, 146mAhg−1 at 1C, 135mAhg−1 at 2C, and 117mAhg−1 at 5C. After 100 cycles, the discharge capacity is 138mAhg−1 at 1C with a capacity retention of 95%. The S-2 sample yields the best electrochemical performance in terms of charge–discharge capacity and rate capability compared with other samples. Its superior electrochemical performance can be mainly attributed to the duplex crystallite structure, composed of fine (<10nm) and coarse (>20) nm nanoparticles, where lithium ions can be stored within the grain boundary interfaces between the spinel Li4Ti5O12 and the anatase TiO2.
A cobalt oxide modified porous carbon has been synthesized via a solvothermal method followed by a simple thermal treatment process. Scanning electron microscopy and transmission electron microscopy images reveal that Co3O4 nanoparticles (NPs) with sizes of 20–40nm are uniformly anchored onto porous carbon (PC). As an anode material for Li-ion batteries (LIBs), the composite exhibits enhanced reversible capacity, excellent cyclic performance, high Coulombic efficiency and good rate capability, which could be attributed to the 3D hierarchical porous structure of PC as well as the small size of the Co3O4 NPs providing convenient and accessible routs for electrolyte diffusion and intercalation of Li ions. Moreover, the interconnective networks of PC could decrease the inner resistance of LIBs and maintain structural stability. Thus the Co3O4/PC composite could be a promising anode material for high-performance LIBs.
Na[FSA–C2C1im][FSA] (C2C1im+:1-ethyl-3-methylimidazolium and FSA−:bis(fluorosulfony)amide) ionic liquid was utilized as the aprotic electrolyte in hybrid sodium–air cells for the first time. The sodium–air cells were operated at relatively high temperatures up to 70°C to prove their excellent thermal stability. A large output power density was obtained by increasing the operation temperature because of the high Na+ diffusivity and high ionic conductivity of the ionic liquid. The cells exhibited an extremely large specific capacity of 835mAhg−1 at 50°C; this capacity corresponds to 99% of the theoretical capacity. In addition, maximum areal output power density of 27.6mWcm−2 was obtained at 50°C. The Na[FSA–C2C1im][FSA] ionic liquid was proved to be a promising aprotic electrolyte to enhance the electrochemical performance of hybrid sodium–air cells.
The practical application study of a time-integrated radon progeny monitor developed by the authors was carried out in and around a closed uranium mine site during several years. The validity of the monitoring with the monitor was confirmed by good agreement with the other monitoring results and our previous investigations. Radon progeny concentrations were almost at same level outside the site and were within the range of those at controls. The fact shows directly the effect of the mine site on the effective dose to people in outside region is negligible. The F value outdoors in rural area around Ningyo-toge is approximately 0.4 on the whole, while the lower values were observed on the site or near the site, and the higher values, closer to 0.6 in UNSCEAR reports, were observed in the large population areas.
Battery as an energy storage system is a key element in Microgrids (MGs). Therefore, determining the optimal size of battery energy storage systems (BESS) can reduce the operational costs of MGs. The goal of this paper is to calculate the optimal size of a BESS in an off-grid MG while minimizing the total cost using convex optimization methods. This paper proposes a new two-step cost-based method to determine the optimal size of a BESS in an MG. In the first step, in order to optimize the operation of the MG, a unit commitment (UC) problem is solved. In the next step, the optimal size of the BESS is determined using convex optimization considering several physical and operational constraints. The resulting problem is a non-convex non-linear problem. However, the problem can be transformed into a convex problem using convex relaxation methods. In the next step, the convexity and feasibility of the optimization problem is proved. The CVX toolbox package integrated with MATLAB is used to solve the problem. To assess the effects of BESS on operational and total costs of the MG, four scenarios are studied. Additionally, the results have been compared with PSO and GA algorithms and effectiveness of the proposed method has been shown.
Newly developed nickel–metal hydride (Ni/MH) micro cells that are capable of high rates, meet the requirements of main power sources for modern wireless telecommunication devices, like GSM hand phones, PDAs and others. Besides having the capability to give high continuous and pulse discharge currents, they also ensure the realisation of a device with slim design and low cost. For the back-up of the RTC function, a lithium-ion cell based on the carbon–manganese dioxide system provides high reliability by having a long cycle life and complete tolerance to deep discharge. For MBU (which require higher rates), a Ni/MH cell only 2mm thick is now being introduced. Other wireless devices, like headsets for comfortable use of mobiles whilst driving, wireless mice and keyboards and the upcoming “Bluetooth” technology will need suitable power sources. Besides the rather high currents, which exclude low-power lithium systems, miniaturisation is limiting the space available for the battery. Some concepts using Ni/MH micro batteries will be discussed in this paper.
The fascinating properties of graphene are attracting considerable attention in engineering fields such as electronics, optics, and energy engineering. These properties can be controlled by controlling graphene's structure, e.g., the number of layers and the sheet size. In this study, we synthesized nanosized graphene from a platelet-type carbon nanofiber. The thickness and size of nanographene oxide are around 1nm and 60nm and we obtained nanographene by hydrazine reduction of nanographene oxide. We applied the nanographene to an ionic-liquid electric double-layer capacitor (EDLC), which exhibited a much larger capacitance per specific surface area than an EDLC using conventional activated carbon. Furthermore, the capacitance increased significantly with increasing cycle time. After 30th cycle, the capacitance was achieved 130Fg−1, though the surface area was only 240m2 g−1. These results suggest that nanographene structure induce the capacitance enhancement.
The integration of two-dimensional (2D) reduced graphene oxide (rGO) and binary metal oxide in a single electrode for asymmetric supercapacitors (ASC) is promising for overcoming the challenges driven by increasing energy-storage demands. In present work, we proposed a novel rGO/FeCo2O4 hybrid electrode as a negative electrode for asymmetric supercapacitors (ASC). Briefly, we engineered 3-dimensional nanocomposite materials by decorating FeCo2O4 nanoparticles on rGO nanosheets using facile strategy. Owing to the strong chemical bonding between the FeCo2O4 nanoparticles and rGO nanosheets, as-prepared rGO/FeCo2O4 hybrid electrode shows an ultrahigh specific capacitance of 1710 F/g on the negative potential side. Later, asymmetric supercapacitor was assembled using MnO2 nanowires as positive electrode and rGO/FeCo2O4 hybrid as negative electrode, respectively. The proposed device achieved a maximum specific capacitance of 260 F/g with a specific energy of 67.5 Wh/kg and exhibited excellent cycling performance (96.02% capacity retention after 5000 cycles). Thus, the proposed design of the high-energy ASC is promising for next-generation energy-storage devices being developed for modern consumer applications.
A mesoporous carbon sphere with the uniform channels (OMC) is employed as the conductive matrix in the sulfur cathode for the lithium sulfur battery based on all-solid-state PEO18Li(CF3SO2)2N–10wt%SiO2 electrolyte. Cyclic voltammograms (CV) and electrochemical impedance spectrum (EIS) suggest that the electrochemical stability of the S-OMCs is obviously superior to the pristine sulfur cathode. The S-OMCs composite shows excellent cycling performance with a reversible discharge capacity of about 800mAhg−1 after 25 cycles. This would be attributed to an appropriate conductive structure in which the active sulfur is highly dispersed in and contacted with the OMCs matrix.
Redox flow batteries (RFBs) are one of the most promising scalable electricity-storage systems to address the intermittency issues of renewable energy sources such as wind and solar. The prerequisite for RFBs to be economically viable and widely employed is their low cost. Here we present a new zinc–iron (Zn–Fe) RFB based on double-membrane triple-electrolyte design that is estimated to have under $100 per kW h system capital cost. Such a low cost is achieved by a combination of inexpensive redox materials (i.e., zinc and iron) and high cell performance (e.g., 676 mW cm−2 power density). Engineering of the cell structure is found to be critical to enable the high power density. Our cost model shows that a Zn–Fe RFB demonstrates the lowest cost among some notable RFBs and could reach the 2023 cost target set by the U.S. Department of Energy ($150 per kW h).
A micro-sized particle Li4Ti5−x La x O12 (0 ≤ x ≤ 0.2) material has been synthesized by a simple solid-state method at air. The obtained Li4Ti5−x La x O12 materials are Li3x La2/3−x TiO3 (LLTO)–Li4Ti5O12 (LTO) solid solution, and well crystallized with a particle size in the range of 1–2 μm. The electronic conductivity and lithium diffusion coefficient of La-modified LTO (Li4Ti4.95La0.05O12) are improved because LLTO exhibits a high ionic conductivity during Li+ extraction. Li4Ti4.95La0.05O12 material shows discharge capacities of more than 206 and 197 mAh g−1 after 100 cycles at 1 C and 3 C charge–discharge rates, respectively. Especially, in rate performance, the Li4Ti5−x La x O12 (x = 0.1, 0.2) samples maintain capacity of about 181 mAh g−1 until 5 C rates after 200 cycles, while the pure LTO sample shows a severe capacity decline at corresponding rate. These results suggest that La modifying is an effective way to improve the chemical stability of the electrode in contact with the electrolyte and improve their cyclability and rate capability during long term cycling. Since high rate performance is an important factor that needs to be considered in fabricating power batteries in industry, the La-modified LTO moves closer to real and large-scale applications.
The sealed Ni/MH batteries with carbon nanotubes (CNTs) in the positive electrodes were assembled. The overall characteristics of Ni/MH batteries were investigated at different charge–discharge cycles at room temperature. The high-rate discharge performance of the Ni/MH battery was improved by the addition of CNTs in the positive electrode. Under high-rate discharge conditions, the batteries with CNTs added in the positive electrodes exhibited much better cycling stability, higher discharge voltage, and high-rate capability. The increase in internal resistance of the batteries with CNTs was lower than that of the batteries without CNTs during charge–discharge cycles. The addition of 0.5wt.% CNTs was proved a desired amount to modify the batteries performance at the high discharge rates. Too much CNTs contributed no effect in the improvement of overall performance of the batteries.
Identifying cerebral vulnerability in late life is of paramount importance to prevent pathological trajectories of aging before the onset of symptoms. Considerable evidence suggests that impaired antioxidant mechanisms are a fingerprint of aging-related conditions, but there is a lack of human research linking total antioxidant capacity (TAC) measured in peripheral blood to in vivo brain changes and other factors featuring accelerated aging. To address this issue, we have assessed in cognitively normal elderly subjects (N = 100) correlations between serum TAC, using the oxygen radical absorbance capacity assay, surface-based cortical thickness, surface-based 18F-fluorodeoxyglucose positron emission tomography cortical uptake, and different factors associated with accelerated aging [i.e., serum homocysteine (HCY), self-reported memory problems, and self-reported patterns of physical activity]. While no relationship was observed between serum TAC and variations in cortical thickness, decreased TAC level was significantly associated with lower FDG uptake in temporal lobes bilaterally. Remarkably, decreased TAC level was linked to increased HCY concentrations, more subjective memory complaints, and lower frequency of physical activity. Overall, our results suggest that decreased serum TAC level may be helpful to detect vulnerable trajectories of aging.
Thermal methods, differential scanning calorimetry (DSC) and thermogravimetry (TG), are highly sensitive analytical techniques that can be used for quality control of the materials and the technological processes during battery manufacture. This paper presents the results of our investigation aimed to estimate the efficiency of the two thermal methods, differential scanning calorimetry and thermogravimetry, for analysis and control of the processes taking place during battery production and operation.
Despite the increased attention on the impacts of globalisation, there has been little empirical investigation into the impact of multinational firms on the domestic labour market and in particular wage inequality, this is in spite of a rapid increase in foreign direct investment (FDI) at around the same time of rising inequality. Using UK panel data, this paper tests whether inward flows of FDI have contributed to increasing wage inequality. Even after controlling for the two most common explanations of wage inequality, technology and trade, we find that FDI has a significant effect upon wage inequality, with the overall impact of FDI explaining on average 11% of wage inequality.
An overview on processes that are relevant in light-induced fuel generation, such as water photoelectrolysis or carbon dioxide reduction, is given. Considered processes encompass the photophysics of light absorption, excitation energy transfer to catalytically active sites and interfacial reactions at the catalyst/solution phase boundary. The two major routes envisaged for realization of photoelectrocatalytic systems, e.g. bio-inspired single photon catalysis and multiple photon inorganic or hybrid tandem cells, are outlined. For development of efficient tandem cell structures that are based on non-oxidic semiconductors, stabilization strategies are presented. Physical surface passivation is described using the recently introduced nanoemitter concept which is also applicable in photovoltaic (solid state or electrochemical) solar cells and first results with p-Si and p-InP thin films are presented. Solar-to-hydrogen efficiencies reach 12.1% for homoepitaxial InP thin films covered with Rh nanoislands. In the pursuit to develop biologically inspired systems, enzyme adsorption onto electrochemically nanostructured silicon surfaces is presented and tapping mode atomic force microscopy images of heterodimeric enzymes are shown. An outlook towards future envisaged systems is given.