batterydata/paper-abstracts huggingface dataset:
The structure of lithium ion battery components, such as electrodes and separators, are commonly characterised in terms of their porosity and tortuosity. The ratio of these values gives the effective transport coefficient of lithium ions in the electrolyte-filled pore spaces, which can be used to determine the ionic resistivity and corresponding voltage losses. Here, we show that these microstructural characteristics are not sufficient. Analysis of tomographic data of commercial separators reveals that different polyolefin separators have similar porosity and through-plane tortuosity, which, in the homogenised picture of lithium ion cell operation, would imply that these different separators exhibit similar performance. However, numerical diffusion simulations indicate that this is not the case. We demonstrate that the extent to which lithium ion concentration gradients are induced or smoothed by the separator structure is linked to pore space connectivity, a parameter that can be determined by topological or network based analysis of separators. These findings enable us to propose how to design separator microstructures that are safer and accommodate fast charge and discharge.
A series of optimized graphite anodes and NMC cathodes with thicknesses from 70μm to 305μm were prepared to study the influence of the ratio of active material to inactive substrate foil on the cycle stability and energy density of lithium ion full cells. Cells with electrodes of up to 155μm thickness showed no capacity losses for C-rates up to C/2 and excellent cycling stability. For thicker electrodes the kinetic losses increased with C-rate and cycle stability deteriorated. However, for a given C-rate and in a realistic cell design, the energy density could be increased by up to 29% compared to the standard thickness.
Patterns of invasion by the seaweeds Grateloupia turuturu Yamada and Sargassum muticum (Yendo) Fensholt under crossed combinations of the regime (mean intensity and temporal variability) of climate-related mechanical disturbance and constant nutrient enrichment were experimentally examined in rockpools in north Portugal. The cover of both species was larger under high compared to low intensity of disturbance, but this effect was enhanced by events more heterogeneously distributed over a period of 19 months. The invasion by G. turuturu was also larger in enriched pools, but only when disturbance was applied at high intensity. The richness of native taxa was increased by high intensity events of disturbance evenly distributed over time and by low intensity events heterogeneously distributed, while no differences were documented for other treatments. Temporal variability of disturbance and nutrients interactively affected the total cover of native taxa and the availability of bare rock in different directions. Enriched conditions increased the space occupancy by natives and reduced substratum availability only when associated to heterogeneous events of disturbance. At the same time, relatively more variable disturbances caused a reduced cover by native taxa and an increased availability of free space, but only under natural nutrient levels. Present findings contribute to understand the conditions that would be more likely to facilitate the spread of G. turuturu and S. muticum under current and predicted scenarios of compounded environmental changes and in relation to traits of recipient systems that are considered relevant for the success of invasions, including the native richness and the degree of usage of resources, i.e. primarily space.
Sunniva R. Collins, associate professor of Mechanical and Aerospace Engineering at Case Western Reserve University (CWRU), has been elected ASM Board President. Collins plans to continue focusing on fostering and growing the ASM community that she became a part of over two decades ago, by asking members to get engaged and volunteer more often in the hopes of sparking new experiences and new engagement among the next generation of members and volunteers. “Since I joined in 1988 and for the majority of my professional life, ASM has remained a critical facet of my career developments, volunteer activities and opportunities to advance the field,” she said. “I’ve made great friends, connected with phenomenal mentors, received industry-leading technical insights, and greatly look forward to giving back to the Society that has given so much to me.”
Na3V2(PO4)2F3 (NVPF) has been attracting great interests as a potential positive electrode for lithium/sodium (Li+/Na+) hybrid batteries. However, it is still not clarified as what type of alkali metal ion is intercalated at different stage in the Na-based cathode material during discharge process. Herein, the intercalation sites and ratios of Li+ and Na+ ions are firstly studied systematically. The results show that the intercalation of Li+ ions is mainly at the original Na1 and Na2 sites. However Li+ ions are metastable in NVPF, and are easy to be replaced by Na+ ions through ion exchange in Na+ ion containing hybrid electrolyte. There exists a competitive insertion between Li+ and Na+ ions caused by the impact of ion exchange rate, and the difference of the ion diffusion speed of Li+ and Na+ ions in the hybrid electrolyte with certain concentration of these two ions. Thus a competitive insertion mechanism of Li+ and Na+ ions in NVPF is proposed. Furthermore, the intercalating ratio of Li+ and Na+ ions can be tuned by controlling the external current density, which can effectively change the ion diffusion speed of Li+ and Na+. Conclusively NVPF with double coating of polytetrahydrofuran and carbon has better rate capability and cycle stability in hybrid electrolyte with Na+ concentration higher than 0.2 mol L−1, which is of potential to be used as cathode material for hybrid batteries with high specific energy.
Processing visual information from a large camera network is important for many applications, such as smart environments, human–computer interfaces, and surveillance. Smart camera motes using onboard processing offer an opportunity to create scalable solutions based on distributed processing of visual information. Wireless communication in sensor networks is preferred for many practical reasons. Wireless smart camera node architecture is analyzed in this chapter.
The effect of magnesium content on the phase structure and electrochemical properties of Ml1−xMgxNi2.78Co0.50Mn0.11Al0.11 (x = 0.05, 0.10, 0.20, 0.30) hydrogen storage alloys was investigated. The results of X-ray diffraction reveal that all the alloys consist of the major phase (La, Mg)Ni3 and the secondary phase LaNi5. With increase in x, the relative content of the (La, Mg)Ni3 phase increases gradually, and the maximum capacity and low temperature dischargeability of the alloy electrodes first increase and then decrease. When x is 0.20, the discharge capacity of the alloy electrode reaches 363 mAh g−1 at 293 K and 216 mAh g−1 at 233 K, respectively. The high rate dischargeability of the alloy electrodes increases with increase in x. When the discharge current density is 1200 mA g−1, the high rate dischargeability of the alloy electrodes increases from 22.0% to 50.4% with x increasing from 0.05 to 0.30. The cycling stability of the electrodes decreases gradually with increase in magnesium content.
The reliability assessment of battery packs is an important topic in the reliability design of electric vehicles. To improve the accuracy of the reliability analysis, a modified reliability model for lithium-ion battery packs is developed that couples multiphysics models, degradation models, and a multistate system reliability model. For the degradation models, a stochastic capacity degradation model and a dynamic response impedance (DRI) model are established based on experimental data: a) the stochastic capacity degradation characteristics of cells are investigated, and b) the dynamic response characteristics of the impedance with degradation and changing temperature are studied. It is found that Weibull distribution is slightly more appropriate than normal distribution when the temperature is 25 °C, then reversed with increasing temperature. The algorithm for distribution selection is proposed to describing this concept drift phenomenon. Then, the influence of DRI on the thermal performance is analyzed. Finally, reliability assessment of battery pack and several calculation examples are implemented for comparative analysis. The results show that the fading rate of cells in battery pack are accelerated when DRI is incorporated. Thus, multiphysics-based system reliability model with considering the stochastic capacity degradation and DRI enables more scientific and accurate reliability evaluation of battery pack.
Li2O–2B2O3 glass-modified LiMn2O4 cathode powders are prepared using spray pyrolysis. The powders with 1 and 5wt% glass material have a spherical shape, dense structure, and large grain size. The BET surface areas of LiMn2O4 powders with 0 and 1wt% glass material are 15.0 and 5.9m2 g−1, and their mean crystallite sizes are 29 and 49nm. The lithium boron oxide (LBO) glass material improves the cycle properties as well as the initial discharge capacities of the LiMn2O4 powders at a constant current density of 1C. The discharge capacity of LiMn2O4 powders without any glass material decreases from 116.3 to 92.6mAhg−1 after 100 cycles, the reduced capacity being 80% of the initial capacity. However, the discharge capacity of the LiMn2O4 powders with 1wt% glass material decreases from 131.0 to 113.2mAhg−1 after 100 cycles; thus, the capacity retention is 86% of the initial capacity.
Numerical simulation is used to explore the influence of particle shape and overall porosity on the liquid phase conductivity, σ eff, inside porous networks, such as electrodes or separators used for lithium-ion batteries. Such battery components are often modelled by a power law, σ eff=ε α σ 0, which relates electrolyte bulk conductivity σ 0 and void volume fraction ε via a Bruggeman exponent α. Frequently, a value of 1.5 is assumed for α. In this work, theoretical and experimental evidence is presented to show that a Bruggeman exponent of 1.5 is often not valid for real electrodes or separator materials. It is found that only idealized morphologies, based on spherical or slightly prolate (i.e. rod-type) ellipsoids, are expected to give rise to a Bruggeman law with an exponent of about 1.3. Porous networks based on other particle morphologies such as oblate (i.e. disk-type) ellipsoids or lamellar or flaky materials increase the tortuous path for ionic conductivity and result either in a significant increase of the exponent α, or in a complete deviation from the power law. These models imply that spherical or slightly prolate ellipsoidal particles should be preferred for batteries where high-rate performance is required and that future separators could be designed with higher ionic conductivity.
In this paper a survey of solar-based driven thermoelectric technologies and their applications is presented. Initially, a brief analysis of the environmental problems related to the use of conventional technologies and energy sources is presented and the benefits offered by thermoelectric technologies and renewable energy systems are outlined. The development history of solar-based thermoelectric technologies is introduced together with the discussion of the existing drawbacks of current systems. Typical applications of the solar-driven thermoelectric refrigeration and the solar-driven thermoelectric power generation are presented in order to show to the reader the extent of their applicability. The application areas described in this paper show that solar-driven thermoelectric technologies could be used in a wide variety of fields. They are attractive technologies that not only can serve the needs for refrigeration, air-conditioning applications and power generation, but also can meet demand for energy conservation and environment protection.
Thermal imaging is a useful modality for identifying preulcerative lesions (“hot spots”) in diabetic foot patients. Despite its recognised potential, at present, there is no readily available instrument for routine podiatric assessment of patients at risk. To address this need, a novel thermal imaging system was recently developed. This paper reports the reliability of this device for temperature assessment of healthy feet.
An approximate solution is presented for the spherical diffusion equation for the spherical particles in a physics-based lithium-ion battery model. This approximate solution is compared to different numerical and analytic solutions for various boundary conditions. These comparisons reveal that our approximate solution can provide accuracy and time-efficiency in simulation. This approximate solution is much faster than the numerical and truncated analytical solutions at high current rate, and shows better long-time accuracy than the short-time analytical solution. This approximate solution can also be used as the porous electrode model.
Specific discharge capacities in excess of 200mAh/g and good reversible cycling behavior between 3.8 and 2.0V has been observed in a lithium cell for α-MnO2 phases with the hollandite structure. A combination of lithia (Li2O) doping and ammonia (NH3) treatment of the active material powder having the composition α-[0.143Li2O·0.007NH3]·MnO2 gave the best electrochemical performance in liquid organic electrolyte (1:1 EC:DMC, 1M LiPF6) coin cells, with metallic Li as the negative electrode. The added lithia forms a defect close-packed array of oxide anions and stabilizes the interior of the 2×2 tunnel of the hollandite structure by partially filling the crystallographic position (0,0,0.5) of the tetragonal unit cell (I4/m) with O2− from the added Li2O. Ammonia treatment is hypothesized to partially fill other lattice vacancies still available within the 2×2 tunnel with the nitrogen atoms from NH3 taking the same position as the oxide anion in the array. The NH3 can further stabilize the cell during lithium insertion/extraction because of its favorable hydrogen bonding ability and Lewis base characteristics.
We study the ion-conductive and electrochemical properties of concentrated poly (ethylene carbonate) (PEC)-based electrolytes with Li salt concentrations greater than 100 mol%. An end-capped PEC having acetate groups (PEC-Ac) was synthesized as a novel polymer matrix for improving the thermal stability and oxidative stability. A concentrated PEC-Ac electrolyte with 120 mol% of LiFSI had a good conductivity of approximately 10−6 S/cm at 40 °C with an excellent Li transference number (t +) of 0.8. Linear sweep voltammetry measurement for the PEC-Ac electrolyte indicates that the oxidation tolerance is more than 5 V, and is greater than that of the original PEC-based electrolyte. A battery test for the LiFePO4 cell using the PEC-Ac electrolyte was conducted for the first time, finding good capacities ranging from 130 to 160 mAh/g and stable cyclability for more than 60 cycles.
Lithium-oxygen (Li-O2) cells are a promising power source, and carbons are an attractive non-metal catalyst for air electrodes. To improve the electrochemical performance, various carbons are heated in an inert atmosphere. It is found that heat treatment at 900°C can differently improve the electrochemical performance of multiwalled carbon nanotubes (CNTs), acetylene carbon black (AB) and activated carbon (AC), but the improvement of CNTs is the most obvious. After heat treatment, the peak current density of the oxygen reduction reaction (ORR) and the 1st discharge capacity of CNTs increase ∼30% and ∼125%, respectively, while the charge transfer reaction resistance and the Warburg diffusion resistance decrease ∼7.0% and ∼11.1%, respectively. AC has the highest charge capacities and capacity retention ratio in spite of little influence by heat treatment. The possible mechanism and reasons are analyzed using different techniques. Microstructure is superior to conductivity for enhancing the rechargeability and the cyclability, and heat treatment is effective for some carbon materials in improving the electrochemical performance of Li-O2 cells.
Lead is a heavy metal that has been used for many centuries and it is still used for various industrial purposes thanks to its physical and chemical characteristics. Human exposure to lead can result in a wide range of biological effects depending upon the level and duration of exposure. Despite the fact that lead has been found capable of eliciting genotoxic responses in a wide range of tests, not all studies have been conclusive. Although several experimental studies have shown that lead may modulate immune responses, data in exposed humans are still preliminary. The purpose of our study was to evaluate the genotoxic and immunotoxic effects of lead exposure in a group of 70 male workers from two Portuguese factories. The control group comprised 38 healthy males. The exposed individuals showed significantly higher levels of lead in blood and zinc protoporphyrin, and significantly lower δ-aminolevulinic acid dehydratase activity than the controls, suggesting a relatively high lead exposure. Nevertheless, the limit of 70μg/dl for lead in blood established by the Portuguese regulation was never reached. Results of the comet assay were not modified by the exposure, but a significant increase in the mutation frequency in the exposed workers was obtained in the T-cell receptor mutation assay. Furthermore, data obtained in the analysis of the different lymphocyte subsets showed a significant decrease in %CD8+ cells and a significant increase in the %CD4+/%CD8+ ratio in exposed individuals with regard to the controls. No clear effect was observed for vitamin D receptor genetic polymorphism on the parameters evaluated. In view of our results showing mutagenic and immunotoxic effects related to lead exposure in occupational settings, it seems that the Portuguese biological exposure limit for lead needs to be revised in order to increase the safety of exposed workers.
We examined the distribution patterns of native animals on Amami-Oshima Island, southern Japan, along a historical gradient of mongoose establishment and estimated the effects of mongoose on the native fauna. To assess the relative abundance of various ground-dwelling animals, we used the following four methods; sensor cameras for exotic mammals, nighttime driving census for nocturnal native vertebrates, line census for ground-dwelling lizards, and adhesive traps for arthropods. The results indicated that seven species with larger body size, including mammals, birds, reptiles, and amphibians, were rarely observed in mongoose-infested area. By contrast, medium-sized animals showed neutral relationships with mongoose establishment. Interestingly, the densities of smaller-sized animals were higher in mongoose-infested area. It could be interpreted that smaller species have increased in abundance through top-down cascades, i.e., decreases in native predators such as frogs and lizards caused by the mongoose have resulted in increases in the abundance of smaller animals. Predation pressures by mongoose and native predators may be canceled out for medium-sized animals, causing neutral responses to mongoose by these animals. This study appears to be the first example that shows the influence of mongoose on a wide variety of native animals. In addition, our findings indicate the importance of considering the food web structure of a recipient ecosystem and contribute to the prediction and assessment of ecological risks caused not only by mongoose, but also by other invasive top predators.
Carbonization of milk-free coconut kernel pulp is carried out at low temperatures. The carbon samples are activated using KOH, and electrical double-layer capacitor (EDLC) properties are studied. Among the several samples prepared, activated carbon prepared at 600 °C has a large surface area (1,200 m2 g−1). There is a decrease in surface area with increasing temperature of preparation. Cyclic voltammetry and galvanostatic charge–discharge studies suggest that activated carbons derived from coconut kernel pulp are appropriate materials for EDLC studies in acidic, alkaline, and non-aqueous electrolytes. Specific capacitance of 173 F g−1 is obtained in 1 M H2SO4 electrolyte for the activated carbon prepared at 600 °C. The supercapacitor properties of activated carbon sample prepared at 600 °C are superior to the samples prepared at higher temperatures.
With Co(NO3)2·6H2O (oxidizer and Co source), Ni(NO3)2·6H2O (oxidizer and Ni source) and citric acid (fuel) as starting materials, cobalt–nickel oxides/C/Ni ternary nanocomposites have been synthesized by a scalable, one-step solution combustion process at only 300 °C within 30 min in air. In these composites, the metallic nickel and amorphous carbon (conductive phases) were in situ formed by the reduction of Ni2+ and carbonization of the excess citric acid during combustion, respectively. Experimental results indicated that the fuel:oxidant and Co:Ni molar ratios in precursor solution showed strong influences on the phase composition, morphology and electrochemical performance of products. With the increase of the fuel dosage, the products transformed from well-crystallized cubic NiO/Ni to Ni (nickel-related phases), then to relatively amorphous Ni/NiO and finally NiO. Electrochemical tests indicated that the optimized product showed a high specific capacitance of 446 F g−1 at 1 A g−1 (or 280 F g−1 at 10 A g−1) with a Co:Ni:C6H8O7 molar ratio of 4:5:86/9. Significantly, besides its mild experimental conditions, the method could be used to prepare cobalt–nickel oxides/C/Ni/CNTs quarternary nanocomposites by simply adding acid-treated CNTs into precursor combustion solution. Thanks to the high electrical conduction of CNTs, the specific capacitance could be further improved up to 579 F g−1 at 1 A g−1, or 350 F g−1 at 10 A g−1.
The electrochemical behavior related to cycle performance and capacity fading for LiV3O8 thin-film positive electrodes has been investigated. These electrodes experience a slight capacity loss over an initial 200 cycles, and the capacity decreases rapidly upon further cycling. This two-stage capacity fading is related to the growth of a surface layer and exfoliation of active materials, which occurs at different stages of the cycling period. The growth of the surface layer is a major reason for the increased impedance. However, it can prevent the dissolution of active materials and retard further electrode degradation, which leads to the gentle decline in capacity over the initial 200 cycles. In the later cycling period, the exfoliation of active materials causes poor electronic contacts in the film and results in severe capacity fading.
Instrumented bottom tripods have provided important data on sediment transport processes on continental shelves and in estuaries for four decades. Since the initial deployment in a tidal channel in Puget Sound, WA, in 1965 numerous tripods have been constructed to investigate bottom boundary layer and sediment dynamics worldwide. Tripod data have led to new understanding of near-bottom wave and current flows in the coastal ocean, and have been crucial to the development of shelf circulation and sediment transport models. Calculations of bottom stress, bottom roughness, and sediment flux that resulted directly from tripod data have been compared to bottom boundary layer model results. Where these have differed, new or revised model components have been developed to improve the skill of the models. The many discoveries that have been made from tripod experiments include dense, near-bottom fluid mud layers that transport large quantities of suspended sediment offshore into deeper regions of the continental shelf. This process has been linked to the seaward progradation of subaqueous deltas and to the boundaries of mid-shelf mud deposits off rivers with high fine-sediment discharge.