batterydata/paper-abstracts huggingface dataset:
Thermodynamics and kinetics of intrinsic point defects in Na2Fe(SO4)2·2H2O, a high-voltage cathode for Na-ion batteries, are studied by means of first-principles density functional theory. Electronic structures of charged defects are calculated to study their influences towards electronic and electrochemical properties as well as to probe hole polaron formation. As defect formation energy strongly depends on atomic chemical potentials, we initiate a systematic approach to determine their valid ranges for the pentrary Na-Fe-S-O-H compound under thermodynamic equilibria and correlate them with approximated pH parameters in solution-based synthesis. Given chemical potential landscape and formation energy, we find that Fe Na 1 + , V Na 1 - , 0 and Na Fe 1 - , 0 are dominant and their concentrations could be manipulated through pH condition and oxygen content in the precursor solution. It is predicted that the channel blockage due to FeNa would appear under strong acidic growth condition but could be diminished under weak acidic condition (4.7 ≤ pH ≤ 5.6) where NaFe facilitates a faster migration between each diffusion channel. Our results do not only explain the origin of intercalation mechanism and improved electronic conduction, but also demonstrates the pH influence towards conductivities in the cathode material.
Solid electrolyte is one of the promising electrolytes to realize safe and high energy density rechargeable lithium metal battery. However, in view of the characteristics and defects of the solid inorganic and polymer electrolytes, the high-performance solid electrolyte is still a challenge for effective application in batteries. Herein, we report a novel inorganic-polymer flexible composite electrolyte prepared through synthetic of chelating copolymers. With synergistic coupling, the active filler-Li1.5Al0.5Ge1.5(PO4)3 can be uniformly distributed and maintains good composite with the polymer matrix. Thereby, this composite structure promotes the electrolyte with increased electrochemical stability and enhanced thermal stability. In our case, the larger volume fraction of continuous interface between the filler and gel polymer layer is helpful to increase ionic conductivity and Li+ ion transference number of composite electrolyte. Specifically, a large amount of fillers as a rigid part can block dendrites and provide effective pathways for lithium ion transfer, meanwhile, the uniform distribution of gel polymer layer on the surface of inorganic particles facilitates a soft contact to reduce the interface impedance and a substantial flexibility to adapt the volume change in electrode. For further illustration, the solid-state lithium battery of LiFePO4/Li using this composite electrolyte shows relatively satisfactory performance, indicating the considerable cycling performance and acceptable rate capability. Thus, owing to its easy processing and compelling characteristics, this type of electrolyte make promise to reshape the feasibility of the high safety, stable and high energy density rechargeable solid-state lithium metal batteries at room-temperature.
A Co3O4-C nanocomposite has been synthesized by a one-step hydrothermal method free of any template with an annealing process. The composite exhibits a flower-like, hollow, and porous skeleton with a large specific surface area of 272.3 m2g−1. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images reveal the hybrid nanostructure comprises ring-like Co3O4 nanocrystals of 20nm in diameter homogeneously embedded in the carbon matrix. Such integrated electrodes exhibit an ultrahigh specific capacity and excellent cycling stability even at a high charge/discharge current density. Cycle exceeds 400 times in half cells at a 5C (5 Ag−1) rate while retaining about 1000 mAhg−1 reversible capacities (where a 1C rate represents a one-hour complete charge or discharge). This study not only provides a simple synthesis method for lithium ion batteries, but also helps in designing novel and high performance electrode materials.
This study investigates the effects of generating inferences (or failure thereof) with incomplete advertising messages on consumer's belief formation. A factorial design is used to systematically investigate the roles of product knowledge, message structure, and inference prompting in this process. The results show that inference generation or failure affects not only the belief per se, but also the confidence in the belief and that strength of learned beliefs about the product tends to be congruent. Specifically, high knowledge consumers' inferred beliefs are stronger, held with higher confidence, and more congruent with their existing beliefs than those of low knowledge consumers. Interaction effects are also observed between product knowledge and message structure for low knowledge consumers. High knowledge consumers are not affected by message structure or inference prompting condition. Implications of these findings for inference-persuasion research, advertising effectiveness, and future research are discussed.
Although atomically dispersed Fe-N species as electrocatalysts often exhibit high activity for oxygen reduction reaction (ORR), the rational design and facile fabrication of single-atom Fe-N species-based catalysts remains a great challenge because of their easy aggregation. Herein, a new precursor of host-guest Fe-TPP⊂rho-ZIF (Fe-TPP = tetraphenylporphyrin iron; rho-ZIF = zeolitic imidazolate framework with the rho topology) for the first time was elaborately designed and readily prepared by one-pot mechanochemical method, and then was pyrolyzed into Fe-N/C catalysts with no need of solution-based steps and post-ammonia/acid treatments, which greatly simplified the preparation procedures. Owing to the host-guest confinement at the molecular level, the encapsulated Fe centers within interior cavities of rho-ZIF host matrice can be effectively isolated during pyrolysis to afford atomically dispersed Fe-N4 moieties anchored on the carbon matrice. Such a well-elaborated precursor not only endows the final product with the single-atom characteristic, but also with high Fe loading (up to 3.8 wt%) and specific surface area. Benefitting from the outstanding compositional and structural advantages, the resultant Fe-N/C exhibits highly efficient ORR activity with E1/2 of 0.895 V in 0.1 M KOH, ~ 50 mV more positive than that of the commercial Pt/C, which is among the top-level ORR electrocatalysts to date. It has excellent stability and displays a negligible change after a 10000-cycle accelerated durability test. Moreover, rechargeable Zn-air batteries were also assembled to demonstrate the practical application of the as-obtained Fe-N/C as air cathode catalyst. Our work may provide an insight into the facile and large-scale production of high-performance and durable non-precious metal catalysts with atomic-level dispersion.
Sponge-like mesoporous beta-manganese dioxide (β-MnO2) with a high specific surface area and narrow pore size distributions has been successfully synthesized at room temperature by a template-free approach. As a supercapacitor electrode, the as-prepared 3D network β-MnO2 exhibits greatly improved electrochemical performance: not only its specific capacitance enhances from ∼15 F g−1 (traditionally hydrothermal synthesized hollow β-MnO2 nanorods) to ∼180 F g−1 in 1 M Na2SO4 aqueous solutions, but also ∼99% of its initial specific capacitance can retain after charge/discharge for 10000 cycles. In addition, its rate retention can maintain at ∼65% as the scan rate increasing from 2 mV s−1 to 50 mV s−1. These results demonstrate that, through modification or improvement, β-MnO2 can also be a promising electrode material for supercapacitors.
Reducing energy consumption and increasing the use of renewable energy in the building sector are crucial to the mitigation of climate change. Wind power driven heat pumps have been considered as a sustainable measure to supply heat to the detached houses, especially those that even do not have access to the electricity grid. This work is to investigate the dynamic performance of a heat pump system driven by wind turbine through dynamic simulations. In order to understand the influence on the thermal comfort, which is the primary purpose of space heating, the variation of indoor temperature has been simulated in details. Results show that the wind turbine is not able to provide the electricity required by the heat pump during the heating season due to the intermittent characteristic of wind power. To improve the system performance, the influences of the capacity of wind turbine, the size of battery and the setpoint of indoor temperature were assessed. It is found that increasing the capacity of wind turbines is not necessary to reduce the loss of load probability; while on the contrary, increasing the size of battery can always reduce the loss of load probability. The setpoint temperature clearly affects the loss of load probability. A higher setpoint temperature results in a higher loss of thermal comfort probability. In addition, it is also found that the time interval used in the dynamic simulation has significant influence on the result. In order to have more accurate results, it is of great importance to choose a high resolution time step to capture the dynamic behaviour of the heat supply and its effect on the indoor temperature.
The conductive properties of butadiene polymer (BR) and styrene-butadiene polymer (SBR) with sodium chlorate (VII) can be used at industrial scale as miniature batteries. Polymer material modified with sodium chlorate (VII) was used to produce sodium polybutadiene and poly(styrene-butadiene) batteries. The conductivity of such polymer composites for temperatures ranging 243–313K is at a similar level and amounts to 10−4 Scm−1 for butadiene polymer and to 10−3 Scm−1 for styrene-butadiene polymer at 100kHz. The conductive battery made of butadiene polymer shows a open circuit voltage of 0.9V with a short-circuit current of 40mA, whereas that made of styrene-butadiene polymer shows a open circuit voltage of 1.2V with a short-circuit current of 38mA. The lightness, commonly found material (sodium), and environment-friendly energy are main advantages of sodium polybutadiene and poly(styrene-butadiene) batteries.
The ionic conductivity of the organic electrolyte in Li-ion batteries has been modelled. The classical one-dimensional Nernst–Planck approach results in a system of two non-linear parabolic second-order partial differential equations. It is shown that under electro-neutrality conditions this complex system of equations can be reduced to simple diffusion equations with modified diffusion coefficient, facilitating the efficient use of numerical methods. As a result, detailed information about transient and steady-state behaviour of the electrolyte is revealed, including potential gradients and the diffusion and migration fluxes for both Li+ and P F 6 − ions. Furthermore, an extension of the basic model is presented, taking into account salt dissociation in the electrolyte. The most characteristics of ionic transportation are illustrated with realistic examples of constant-current (dis)charging Li-ion batteries. Some of the numerical simulations are compared with recently reported experimental results.
Morphology-controlled LiMn0.9Fe0.1PO4 nanoplatelets as high performance cathode material for lithium ion batteries have been synthesized via a simple ascorbic acid-assisted solvothermal process in water-ethanol solvent. The phase structure and morphology of the products were characterized by XRD, SEM and TEM. The results reveal that decreasing the crystallite size along b-axis direction and increasing the surface area of (010) plane can shorten Li+ diffusion path and increase the electrode reaction activity. The LiMn0.9Fe0.1PO4 nanoplatelet holds the high capacity of 145 mA h g−1, 134 mA h g−1, 119 mA h g−1, 97 mA h g−1 and 68 mA h g−1 at 0.1 C, 0.5 C, 1 C, 5 C and 10 C respectively, and it can retain 75% of the initial reversible capacity even after 100 cycles at 10 C rate.
Seasonal variations of DNA-adduct levels in peripheral blood cells were evaluated in open field farmers (n =26) by use of the 32P-postlabelling assay. Samples were collected before (sample S0) and during (sample S4) the period of intensive pesticide use. A similar sampling procedure was applied to a referent group (n =29). Exposure to pesticides was estimated via a detailed questionnaire. For the group of farmers, an increase in mean adduct level was observed during the season (mean RALS0 =3.9±3.4×10−10, mean RALS4 =13.3±15.7×10−10; p =0.008; RAL=relative adduct level). The mean adduct levels were significantly different between farmers and referents only in the S4 samples, with higher levels for farmers (p =0.02). The number of different adducts per individual was higher for farmers at S4 when compared with S0 (p =0.02) and compared with the referents at S4 (p =0.03). However, the increase of the adduct level in farmers did not seem to be attributable to the occurrence of specific new adducts in S4 as compared with S0, but was supposedly due to intensification of pre-existing spots and/or appearance of new unspecific ones. This would be in agreement with indirect genotoxic (epigenetic) effects known for several pesticides, even though a direct mechanism cannot be ruled out definitively. The implication of the pesticides used by the farmers in the modulation of DNA-adduct patterns was explored by analysis of exposure data obtained from the questionnaire.
A new strategy based on a real-time switching of the fueling regulators’ inputs is proposed in this paper to achieve better fuel saving for the fuel cell systems. The performance of the proposed strategy is compared with two basic strategies that operate in full loading range. In fact, by splitting the operating range in two ranges, where each basic strategy operates best, the proposed strategy mixes the benefits of these two strategies. The switching threshold between the loading ranges is optimally set using the sensitivity analysis. The fuel savings for all strategies analyzed in this study are compared to those obtained using the static feed-forward strategy for fueling regulators. The load-following mode for fueling regulators is implemented based on switching rule of the basic strategies, comparing the load demand with the aforementioned switching threshold. The load-based control provides huge advantages regarding battery size and operation in charge-sustained mode (which increases its lifetime). The best fuel saving can be obtained in real-time based on search flexibility on the optimization surface (with two variables). Compared with the best basic strategy, the fuel saving is 1.63 and 2.07 – times higher for a pulsed load and stair load, respectively. Also, compared with the total fuel consumption of the static feed-forward strategy, the fuel saving is 25.87% and 13.72% for the aforementioned load profiles. The obtained results are good and can motivate the further research in order to test and validate this strategy for fuel cell vehicles.
A pack level passive thermal management system has been designed, developed and experimentally investigated using a phase change composite material. Three 20Ah capacity LiFePO4 prismatic cells connected in series are used to form the battery pack and phase change composite material of different thicknesses are tested. The battery pack has been charged at 1C and discharged at 1C, 2C, 3C and 4C. A total of 18 thermocouples are used to measure the temperature at the principal surface of all three cells. The results obtained with the phase change composite material are compared with no cooling and liquid cooling options. The results show that, with the use of 6mm thick phase change composite material plates, the battery surface temperature reduces from 56.5°C at no cooling to 36.5°C at a 4C discharge rate. Even at a 1C discharge rate, the temperature of the battery pack drops from 33.5°C with no cooling to 29.1°C with phase change material plates. It is also observed that the effect of an increase in phase change material thickness on the battery pack temperature is insignificant beyond a 6mm thick plate. The results show that the temperature gradient is significantly lower with phase change composite material compared to no cooling and liquid cooling.
The ubiquity of silicon in the semiconductor industry and its unique charge transport features has consistently fueled interest in this element and recent realization 2D silicene is a new feather in its cap. In what could be considered as opening up the Pandora's box with many possible virtues, buckled silicene, planar graphene and a host of other newly discovered 2D materials have redefined a whole new paradigm of research. To this end, the quest for new 2D materials and finding potential applications, particularly to the realm of energy storage, is a curiosity driven task. From first principle density functional theory studies, a newly reported graphene like 2D material Si2BN is investigated as a probable anode material for Li and Na ion batteries. In contrast to pristine silicene, which is inherently buckled, the material Si2BN is planar. However, an interesting transition from planar to buckled structure takes place upon subsequent adsorption of Li and Na ions. Concomitantly, this transition is associated with superior specific capacity (1158.5 and 993.0mAh/g respectively for Li and Na) which is significantly higher than several other 2D analogues. Furthermore, the substrate Si2BN regains the planar structure on subsequent desorption of ions and stability of the material remains intact, as evidenced from ab initio molecular dynamics simulations. As we delve deep into the electronic structure and compute the diffusion pathways and barriers, it is observed that the ionic diffusion is very fast with significantly lesser barrier heights, particularly for Na-ion. These findings suggest that for the 2D Si2BN, there is no diminution in order to be a potential anode material for Li and Na ion batteries.
In this paper, Al2O3-coated separator with developed porous channels is prepared to improve the electrochemical performance of lithium sulfur batteries. It is demonstrated that the Al2O3-coating layer is quite effective in reducing shuttle effect and enhancing the stability of the sulfur electrode. The initial discharge capacity of the cell with Al2O3-coated separator can reach 967 mAh g−1 at the rate of 0.2C. After 50th charge/discharge cycle, this cell can also deliver a reversible capacity of as high as 593.4 mAh g−1. Significantly, the charge-transfer resistance of the electrode tends to be reducing after using Al2O3-coated separator. The improved cell performance is attributed to the porous architecture of the Al2O3-coating layer, which serves as an ion-conducting skeleton for trapping and depositing dissolved sulfur-containing active materials, as confirmed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).
X-ray absorption spectroscopy (XAS) study on the nickel and vanadium oxide LiNiVO4 gives a lot of information on the local structural changes and the redox processes involved upon lithium uptake. This paper is mainly devoted to the comparison between the behaviors of two pristine materials which differ only by the annealing temperature. The general behavior at the atomic level is identical: in a first step, a reduction and a coordination change of vanadium from tetrahedral to octahedral, then a reduction and pairing of nickel, and few changes for the main part of the lithium uptake. The reversibility is insured by vanadium which move from octahedra to tetrahedra and is reoxidized to its pristine oxidation state. From the XAS results, we may conclude that the differences in the electrochemical curves is due to side reaction with the electrolyte.
LiNi0.5Mn1.5O4 powder was synthesized via sol–gel method and coated with ZnO in order to test the electrochemical cyclability of the material as a cathode for the secondary Li battery in the 5 V range at 55°C. The ZnO-coated LiNi0.5Mn1.5O4 powder nearly maintained its initial capacity of 137 mA h g−1 after 50 cycles whereas the uncoated powder was able to retain no more than 10% of the initial capacity after 30 cycles. TEM analysis of the cycled cathodes suggests that the formation of the graphitic surface phase, hindering the Li migration, may be responsible for the rapid capacity loss of the uncoated material while no such phase was observed on the surface of the ZnO coated LiNi0.5Mn1.5O4 powder.
Capacity fade of Sony US 18650 Li-ion batteries cycled using different discharge rates was studied at ambient temperature. The capacity losses were estimated after 300 cycles at 2C and 3C discharge rates and were found to be 13.2 and 16.9% of the initial capacity, respectively. At 1C discharge rate the capacity lost was only 9.5%. The cell cycled at high discharge rate (3C) showed the largest internal resistance increase of 27.7% relative to the resistance of the fresh cells. The rate capability losses were proportional with the increase of discharge rates. Half-cell study and material and charge balances were used to quantify the capacity fade due to the losses of primary active material (Li+), the secondary active material (LiCoO2/C)) and rate capability losses. It was found that carbon with 10.6% capacity loss after 300 cycles dominates the capacity fade of the whole cell at high discharge rates (3C). A mechanism is proposed which explains the capacity fade at high discharge rates.
A high-powered concentration-gradient cathode material with an average composition of Li(Ni0.85Co0.12Mn0.03)O2 has been successfully synthesized by a co-precipitation method. The Li(Ni0.85Co0.12Mn0.03)O2 has a core of Li(Ni0.9Co0.1)O2 that is rich in Ni and a concentration-gradient shell having decreased Ni content and increased Mn content. The electrochemical properties of the concentration-gradient material are studied and compared to those of the core Li(Ni0.9Co0.1)O2 material alone. In the concentration-gradient material of Li(Ni0.85Co0.12Mn0.03)O2, the Ni-rich core delivers a very high capacity, while the Mn-rich concentration-gradient shell improves the cycling stability and rate performance. The electrochemical properties of this cathode material are found to be far superior than those of the core Li(Ni0.9Co0.1)O2 material. At room temperature, the initial capacity of the concentration-gradient Li(Ni0.85Co0.12Mn0.03)O2 is 195 mAh g−1 at 1C between 2.8 and 4.3 V and retains 95.5% after 100 cycles. Moreover, the composite has a good rate performance with a high capacity of about 190 mAh g−1 even at 2C rate.
Systematic electrochemical studies and scanning electron microscopy (SEM) observations were carried out on the anodic formation and cathodic reduction of dense AgCl (about 20 μm thick) on a planar silver substrate in 0.1 mol dm−3 HCl at room temperature. Special attention was given to the ionic conductivity of the AgCl deposit layer. In the major period of anodic growth of AgCl, partially solvated Ag+ ions in inter-grain microchannels were thought to be the main charge carrier. A model featuring periodical changes in the accessibility of microchannels to electrolyte solution was proposed to explain various phenomena, including overpotential fluctuation and complex changes of surface morphology. The initial stage of AgCl reduction was thought to be essentially the reverse process of AgCl growth. But the microchannels were soon broadened so that the electrolyte solution in channels became the main support of ionic conduction. The porous silver layer resulting from reduction of the dense AgCl had a porosity of 60%, which was determined by the difference in molar volume between AgCl and Ag. The average diameter d (μm) of Ag particles and the current density j (mA cm−2) of reduction were found to follow approximately a linear equation in the j range studied (0.2–3.2 mA cm−2): d=0.19−0.24log j.