batterydata/paper-abstracts huggingface dataset:
We synthesized nanocomposite anodes for lithium-ion batteries consisting of carbon enwrapped Si/SiOx core-shell nanoparticles in order to address the poor cycling performance of silicon and the low initial coulombic efficiency related to SiOx-based materials. In particular, we used varying carbon coating times to examine the effects of carbon growth on the amorphous SiOx layer that critically determines the nanocomposites’ electrochemical properties. Through careful microstructure analysis, three steps for carbon growth on SiOx are suggested. Furthermore, the effects of this stepwise carbon growth on the electrochemical properties of the nanocomposites are investigated. Finally, the optimum carbon coating condition for best electrochemical performance of the nanocomposites is proposed. The nanocomposite with optimal carbon layer thickness provides a high capacity (2167mAhg−1 at 0.5Ag−1) with a notably improved initial coulombic efficiency (76%), excellent cycling performance (84% capacity retention up to 50 cycles) and significantly reduced swelling. The novel nanocomposite synthesis is simple and cost-effective, and as a result a promising approach for future mass production of high-performance composite anode.
The estimation of battery remaining discharge capacity (Q RDC ) is essential for the remaining driving range prediction on pure electric vehicles. A traditional Q RDC estimation method is based on the determination of battery state of charge (SOC), in which the estimation accuracy could be affected by the variation in discharge conditions. In this research, a novel Q RDC estimation method through differential voltage (dV/dQ) analysis is introduced for lithium-ion batteries. Through analyzing the characteristics of terminal voltage variation, the present Q RDC could be estimated by the dV/dQ value, which is capable to provide an accurate estimation result under various discharge conditions. On a commercial lithium-ion battery, the dV/dQ method is implemented for Q RDC estimation under pulse discharge profiles and dynamic profiles. The result shows that the dV/dQ method could provide accurate Q RDC estimation results under various discharge profiles in the latter part of the discharge process, and the Q RDC estimation accuracy could hence be improved by combining the differential voltage analysis with the SOC-based method. Owing to the simple computation process, the dV/dQ-based estimation method is very competitive in onboard applications.
The aim of this study is to perform an economic and environmental feasibility study of switching the electrical power supply of a small building located in Dhahran, Saudi Arabia, from the electrical grid into renewable energy provided by solar photovoltaic (PV) modules. The PV power plant is evaluated based on the international Photovoltaic Project Model with the same power capability of 12kW. The feasibility study was based on the new electricity tariffs for the governmental and commercial sectors of 4.0 and 8.0cents/kWh, respectively. Three scenarios were considered for several cities of Saudi Arabia, taking into account the most recent prices for a PV system. The first two scenarios were evaluated with the same input parameters except for the electricity tariff (USD/kWh) for a complete switching from grid electricity to a solar PV system. The equity payback periods were found to be 14.1 and 8.2 years, respectively. The reduction in the equity payback period by doubling the electricity tariff is about 41%. Significant differences were not observed when the techno-economic data for the different cities were compared, most likely due to the similar climate of the cities. The resulting reduction in GHG emissions is about 70 tCO2. A third scenario with partial power switching was evaluated for Dhahran for comparison purposes. In this scenario, the power demand is met by both solar PV (27%) and grid electricity (73%). The equity payback period is significantly increased to 21.7, while the reduction in GHG emissions is a minimum at 23 tCO2.
It is commonly held that the various granzymes (lethal proteases produced by cytotoxic lymphocytes) utilize their different substrate preferences to bring about various forms of target cell death. Although a considerable body of evidence supports this view, it has now become clear that human granzyme H could have evolved a proteolytic specificity that both interferes directly with adenovirus replication and prevents the virus from blocking the potent pro-apoptotic activity of granzyme B.
Our recent studies showed that nanowire based DSSCs exhibited over 250 mV higher open circuit potentials (VOC) compared to those using nanoparticles. In this study, the electron transport and surface properties of nanowires and nanoparticles are investigated to understand the reasons for the observed higher photovoltages with NW based solar cells. It was seen that, in addition to slow recombination kinetics, the lower work function of SnO2nanowires compared to the nanoparticle counterparts also significantly contributes to the high VOC observed for the nanowire based DSSCs.
A highly reversible air electrode was designed based on the hydrophilic nano-PPy tubes with abundant gas diffusion channels and reaction space which greatly improved the cell capacity, cycling stability and especially the rate performance of the lithium–oxygen batteries.
Graphene-winged carbon nanotubes (G-CNTs) have been prepared by the well-controlled outer-wall peeling of the multi-walled carbon nanotubes (MWCNTs). The final hybrid structure features the few layers of graphene nanosheets attaching to the intact inner walls of CNTs. On one hand, the outer branched graphene nanosheets could suppress the aggregation of CNTs and introduce abundant defects and active-edges for easily accessible chemical interaction. On the other hand, the CNTs could bridge the graphene nanosheets for rapid electron transfer and mechanical robustness. As a result, the G-CNTs was used as the electrode materials exhibiting an extremely steady reversible capacity of 603 mAh g−1 over 2200 cycles at a current density of 1 A g−1 (the corresponding area capacity is 0.16 mAh cm−2 at a current density of 0.26 mA cm−2) and owning a high rate capability much superior to those of the pristine MWCNT-based counterparts. The hierarchical G-CNTs architecture provides a new material platform for development of advanced energy-storage devices.
Nanometer β-Ni(OH)2, showed by XRD, was prepared by our supersonic coordination–precipitation method, with an average grain size of about 50nm by TEM. Proton diffusion coefficient of nanometer Ni(OH)2 and spherical Ni(OH)2 were 1.93×10−11, and 5.50×10−13 cm2/s, respectively, with combination of chronocoulometry and cyclic voltammetry. Charge–discharge test of simulated batteries at 0.2°C showed that addition of 8mass% of our prepared nanometer Ni(OH)2 in nickel hydroxide electrodes led to increases in cathode discharge specific capacity (CDSC) by nearly 10% and the chargeability of the electrode by about 50mAh/g, and a decrease in polarization. Cycle life test of AA-type MH-Ni batteries discovered that effect of nanometer Ni(OH)2 in increasing CDSC was more apparent for the first 100 cycles and not much difference was found after 350 cycles. XAS demonstrated a higher oxidation state of Ni in fully charged nanometer Ni(OH)2 composite electrode (Nano-E) and a lower one in discharged Nano-E, compared with micrometer Ni(OH)2 spherical electrodes (Micro-E). A larger structure distortion was found in Nano-E, offering more vacancies for proton diffusion. Thus conversion between Ni2+ and Ni3+ was promoted during the charge–discharge process, which was assumed to be one explanation of increasing CDSC with the addition of nanometer Ni(OH)2.
Two kinds of nongraphitizable carbon were applied as active materials of negative electrodes in Li-ion batteries. The thermal properties of cycled electrodes mixed with or without commercial 1M LiPF6/EC–DMC electrolyte were investigated by TG–DSC from room temperature to 400°C at a heating rate of 5°C/min. Both kinds of lithiated electrodes showed exothermic peaks at about 310°C due to decomposition of SEI by lithiated carbon powder. For the mixture of delithiated electrodes and electrolytes, the heat generation was attributed mainly to thermal decomposition of the electrolyte at about 280°C. But for the mixture of lithiated electrodes and electrolytes, thermal risk mainly came from the reaction between original/secondary SEI and intercalated Li ions, which caused drastic heat generation at about 285°C. Moreover, the thermal behavior of the mixture of cycled electrodes and electrolytes was directly related to the ratio between electrodes and coexisting electrolytes. When the ratio between electrodes and electrolytes was suitable, an endothermic reaction between SEI and electrolytes became dominant and depressed other exothermic heat, which reduced the thermal risk of the mixture of electrodes and electrolytes at elevated temperature.
The Magnéli phase titanium oxide films prepared by cathodic electrodeposition on indium–tin-oxide coated glass substrates from saturated peroxo-titanium solution in acetonitrile. Electrodeposited brownish semi-conductor thin films were identified via X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy (SEM). The effects of different potentials and temperatures on the crystallinity of the thin films have been discussed. Ti3O5, Ti4O7 and Ti5O9 as the most favorable forms of the TinO2n−1 were electrodeposited on ITO electrode at electrochemical deposition potentials and different temperatures. The present investigation reveals that the electrochemical deposition of crystalline TinO2n−1 films by a simple one-step electrodeposition method (without any heat treatment) in acetonitrile solution is possible and very promising as a preparation method for electrochemical applications.
A 40Wh/kg Li-ion battery using a Li4Ti5O12 nanostructured anode and a composite activated carbon LiCoO2 cathode was built using plastic Li-ion processing based on PVDF-HFP binder and soft laminate packaging. The specific power of the device is similar to that of an electrochemical double-layer supercapacitor (4000W/kg). The high power is enabled by a combination of a nanostructured negative electrode, an acetonitrile based electrolyte and an activated carbon/LiCoO2 composite positive electrode. This enables very fast charging (full recharge in 3min). The effect of electrode formulation and matching ratio on energy, power and cycle-life are described. Optimization of these parameters led to a cycle-life of 20% capacity loss after 9000 cycles at full depth of discharge (DOD).
Recent estimates suggest that approximately 40% of global electricity demands can be met by capturing the potential energy contained in the mixing of seawater and freshwater at coasts. Several technologies are currently being explored to capture this energy and maximize the achievable electrical power density. Here we report a new method to capture this energy that yielded a peak power density of 12.6 ± 0.5 W m−2-membrane area (average = 3.8 ± 0.1 W m−2), which is the highest value reported to date for salinity gradient energy technologies fed with synthetic seawater (30 g L−1 NaCl) and freshwater (1 g L−1 NaCl). This unprecedentedly high power density was achieved in a concentration flow cell containing non-toxic copper hexacyanoferrate electrodes that developed electrode potentials based on Na+ activities and an anion-exchange membrane that developed a Donnan potential based on Cl− activities. The peak power density increased to 26.3 ± 1.3 W m−2 (average = 9.4 ± 0.9 W m−2) when using a highly saline synthetic brine (300 g L−1 NaCl) and freshwater (1 g L−1 NaCl). Stacking two flow cells in series doubled the total power while maintaining the same power per membrane area. Combining electrode and Donnan potentials in a concentration flow cell offers a new means to harvest salinity gradient energy that may lead to an economically viable technology.
A detailed and multi-technique study on the kinetics and mechanism of the electrodeposition of Prussian blue (PB) over iron filled-carbon nanotubes (CNTs) thin films is presented here. PB is electrochemically synthesized through a heterogeneous reaction between iron species encapsulated into CNTs and ferricyanide ion in aqueous solution. The reaction was followed by a combination of in-situ or ex-situ measurements through UV–Vis spectroscopy, cyclic voltammetry, Raman spectroscopy and scanning electron microscopy. The analysis of the evolution of a new parameter that we called coverage ratio as well as an innovative way to associate the data extracted from cyclic voltammetry with the electrochemical reaction, are introduced by the first time. Similar response vs. time profiles are obtained from absorbance, charge, current, band intensity in Raman spectra, particle size, and coverage ratio, yet providing different aspects of the growth mechanism. Electrochemical data demonstrates an initial mixed control process related to the iron releases from the CNTs cavities and nucleation, followed by a diffusion limited regime on the growth of PB. Spectroscopic data indicates pseudo-first order kinetics, dependent on ferricyanide concentration, and the rate limited by the iron releases from the CNTs. Both particle size of PB and coverage ratio show a progressive nucleation of PB corroborating the proposed mechanism. Raman data also confirm the PB growth rate over the CNTs walls and evidence of PB/CNT interactions during voltammetric cycles. This multi-technique approach gives insights on different aspects of PB electrodeposition and can be extended to a wide class of different materials.
The influence of the content of SiO2 (in the form of a soot) on the capacity and the self-discharge of lead–acid batteries, as well as on the structure of gelled-electrolyte, is studied in detail by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy and scanning electron microscopy. The content of SiO2 and the viscosity of the gelled-electrolyte are important factors which affect the capacity of batteries. A comparison of cyclic voltammograms indicates a change in the electrochemical behaviour of the lead electrode in the presence of SiO2. The reaction resistance increases as a function of the SiO2 content. The mechanism of the effect of the content of silica soot on electrode capacity and on the performance of gelled-electrolyte is discussed.
A layered potassium vanadate K0.23V2O5 has been successfully prepared by the hydrothermal method and evaluated as an anode material for lithium-ion and potassium-ion batteries. High structural stability is demonstrated by the ex situ X-ray diffraction (XRD) and ex situ scanning electron microscopy (SEM). When used as an anode material for lithium-ion batteries, the K0.23V2O5 exhibits a reversible capacity of 480.4 mAh g−1 at 20 mA g−1 after 100 cycles and 439.7 mAh g−1 at 200 mA g−1 after 300 cycles as well as good cycling stability. Even at a high current density of 800 mA g−1, a high reversible capacity of 202.5 mAh g−1 can be retained, indicating excellent rate performance. Whereas in potassium-ion batteries, it retains a capacity of 121.6 mAh g−1 after 150 cycles at 20 mA g−1 and 97.6 mAh g−1 at 100 mA g−1 after 100 cycles. Such superior electrochemical performance of K0.23V2O5 can be ascribed to the special flower-like morphology and structure. Overall, the results highlight the great potential of K0.23V2O5 as an anode material for both lithium-ion and potassium-ion batteries.
Catalysts for the oxygen reduction reaction (ORR) were prepared by the high-temperature pyrolysis of acetonitrile over Vulcan carbon XC-72, and Vulcan carbon impregnated with 2 wt% Fe or 2 wt% Ni in the form of an acetate salt. The catalysts were characterized by BET surface area analysis, BJH pore size distribution, electrical conductivity testing, transmission electron microscopy (TEM), temperature-programmed oxidation, thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and rotating disk electrode half-cell testing. The most active catalysts were formed when Fe was added to the support before the pyrolysis; however, samples in which Ni or no metal was added still showed increased activity for oxygen reduction compared with untreated carbon. The most active catalyst had a significantly higher amount of pyridinic nitrogen, as determined from XPS. A hypothesis has been proposed to explain this trend based on the formation of different nanostructures depending on which support material is used for the acetonitrile decomposition. According to this proposed explanation, nitrogen-containing carbon samples with nanostructures resulting in exposure of more edge planes (the plane in which pyridinic nitrogen is found) will be more active for the ORR. TEM images of the samples strongly support this hypothesis. Further research is needed to positively identify the active site for oxygen reduction; however, this site is likely located on carbon edge planes.
The state-of-energy of lithium-ion batteries is an important evaluation index for energy storage systems in electric vehicles and smart grids. To improve the battery state-of-energy estimation accuracy and reliability, an online model-based estimation approach is proposed against uncertain dynamic load currents and environment temperatures. Firstly, a three-dimensional response surface open-circuit-voltage model is built up to improve the battery state-of-energy estimation accuracy, taking various temperatures into account. Secondly, a total-available-energy-capacity model that involves temperatures and discharge rates is reconstructed to improve the accuracy of the battery model. An extended-Kalman-filter and particle-filter based dual filters algorithm is then developed to establish an online model-based estimator for the battery state-of-energy. The extended-Kalman-filter is employed to update parameters of the battery model using real-time battery current and voltage at each sampling interval, while the particle-filter is applied to estimate the battery state-of-energy. Finally, the proposed approach is verified by experiments conducted on a LiFePO4 lithium-ion battery under different operating currents and temperatures. Experimental results indicate that the battery model simulates battery dynamics robustly with high accuracy, and the estimates of the dual filters converge to the real state-of-energy within an error of ±4%.
Successions of lake ecosystems from clear-water, macrophyte-rich conditions into turbid states with abundant phytoplankton have taken place in many shallow lakes in China. However, little is know about the change of carbon fluxes in lakes during such processes. We conducted a case study in Lake Biandantang to investigate the change of carbon fluxes during such a regime shift. Dissolved aquatic carbon and gaseous carbon (methane (CH4) and carbon dioxide (CO2)) across air–water interface in three sites with different vegetation covers and compositions were studied and compared. CH4 emissions from three sites were 0.62±0.36, 0.70±0.36, and 1.31±0.57mgm−2 h−1, respectively. Correlation analysis showed that macrophytes, rather than phytoplankton, directly positively affected CH4 emission. CO2 fluxes of three sites in Lake Biandantang were significantly different, and the average values were 77.8±20.4, 52.2±14.1 and 3.6±26.8mgm−2 h−1, respectively. There were an evident trend that the larger macrophyte biomass, the lower CO2 emissions. Correlation analysis showed that in different sites, dominant plant controlled CO2 flux across air–water interface. In a year cycle, the percents of gaseous carbon release from lake accounting for net primary production were significantly different (from 39.3% to 2.8%), indicating that with the decline of macrophytes and regime shift, the lake will be a larger carbon source to the atmosphere.
Purpose We investigated whether duration of untreated psychosis (DUP) prior to first presentation was associated with cognitive function in first episode psychosis (FEP) subjects. We predicted that longer DUP would be associated with greater neurocognitive impairment. Method 180 subjects with schizophrenia (and 93 subjects with Other Psychoses) performed a neurocognitive battery assessing IQ, verbal learning, working memory, visual learning and speed of processing. DUP was defined as the number of days between first onset of psychotic symptoms and first contact with psychiatric services. Results Longer DUP was associated with impaired performance in verbal IQ (p =0.04), verbal learning (p =0.02), and verbal working memory (p =0.04) in FEP subjects with schizophrenia. These associations remained significant for verbal IQ when scores were corrected for age, gender, educational level and ethnicity. Conclusions Longer DUP is associated with poorer neurocognitive ability in schizophrenia subjects at time of first presentation. Since this was a cross-sectional study we can not tell whether longer DUP was a cause or a consequence of the poorer performance.
The comet assay has been recently validated as a sensitive and specific test system for the quantification of DNA damage. The objectives of this study are to investigate the utility of comet assay for detecting mutagens with 11 substances that demonstrated positive results in at least one test among four standard short-term genotoxicity tests, and to evaluate its ability to predict rodent carcinogenicity. Out of 11 test substances, positive comet results were obtained for colchicine, hydroxyurea and actinomycin D. No effect on DNA migration, determined as the tail moment, was found with theophylline or 2,4-dinitrophenol. Bisphenol A, vinblastine, paclitaxel and p-anisidine appeared cytotoxic clastogens because these induced tail moment at concentrations showing 60% or less cell survival. In addition, among three test substances showing the bimodal distribution of DNA damage, which is a characteristic of apoptosis, true apoptosis result was obtained for camptothecin and dexamethasone with the Annexin V affinity assay. With this limited data-set, an investigation into the predictive value of these short-term genotoxicity tests for determining the carcinogenicity showed that comet assay has relatively high sensitivity and superior specificity to other four short-term genotoxicity assay. Therefore, our data suggest that comet assay, especially in combination with apoptotic assay, would be a good predictive test to minimize false-positives in evaluation of the potential rodent carcinogenicity.
In this paper, a new kind of ceramic-coating separator for lithium-ion batteries is successfully prepared by forming a ceramic layer consisted of Al2O3 powder, carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) mix binder onto one side of pristine PE separator. During the preparation of the separator, water is used as solvent and a very small amount of SBR–CMC mixture is applied as binder to obtain better thermal stability. The effect of thickness of the ceramic-coating layer on its thermal stability, physical properties and electrochemical performance is also investigated. The results clearly showed that the ceramic-coating separator with SBR–CMC binder has wonderful thermal stability, good wettability and high uptake of liquid electrolyte. Pouch cell tests with the ceramic-coating separator also show excellent stable cycle performance.