batterydata/paper-abstracts huggingface dataset:
Nanocomposites of Si/C were synthesized from Si and polystyrene (PS) resin using high-energy mechanical milling (HEMM) followed by subsequent heat-treatment. The resultant nanocomposites are comprised of amorphous carbon and nanocrystalline silicon as verified by X-ray diffraction (XRD). The XRD results also indicate the presence of iron silicide (FeSi) arising as a contaminant during HEMM. The Si/C nanocomposite corresponding to Si:C = 1:2 composition obtained after milling in two stages of 12h each for a total time period of 24h shows a capacity as high as ∼850mAh/g with reasonable capacity retention (∼1.1% loss/cycle). The increase in either heat-treatment temperature or milling time renders the nanocomposites more stable at the expense of capacity. Transmission electron microscopy (TEM) analysis shows that the HEMM derived Si nanocrystallites <50nm in size are distributed homogeneously within the amorphous carbon matrix.
The purchase of multifuel vehicles (MFVs) has been incentivized by policies across the globe. Such vehicles are able to operate on more than one source of energy, so they introduce fuel (or energy) choice as one additional dimension consumers decide about. As fuels differ in terms of carbon emissions, this choice has environmental effects. Using 12 years of monthly Swedish data, here I show that the majority of MFV drivers purchase petrol when it is priced at parity with ethanol. Through policy simulations, I document that fossil fuel taxes have limited success in making drivers switch to alternative fuels and can generate economic distortions. The findings question the cost-effectiveness of programmes to incentivize the purchase of MFVs that ignore the fuel choice dimension and highlight the importance of accounting for fuel choice in the analysis of public policy and emerging technologies.
Global wind power and photovoltaic (PV) installed capacities are growing at very high rates (20% per year and 60% per year, respectively). These technologies require large, ‘up-front’ energetic investments. Conceptually, as these industries grow, some proportion of their electrical output is ‘re-invested’ to support manufacture and deployment of new generation capacity. As variable and intermittent, renewable generation capacity increases grid penetration, electrical energy storage will become an ever more important load-balancing technology. These storage technologies are currently expensive and energy intensive to deploy. We explore the impact on net energy production when wind and PV must ‘pay’ the energetic cost of storage deployment. We present the net energy trajectory of these two industries (wind and PV), disaggregated into eight distinct technologies—wind: on-shore and off-shore; PV: single-crystal (sc-), multi-crystalline (mc-), amorphous (a-) and ribbon silicon (Si), cadmium telluride (CdTe), and copper indium gallium (di)selenide (CIGS). The results show that both on-shore and off-shore wind can support the deployment of a very large amount of storage, over 300 hours of geologic storage in the case of on-shore wind. On the other hand, solar PV, which is already energetically expensive compared to wind power, can only ‘afford’ about 24 hours of storage before the industry operates at an energy deficit. The analysis highlights the societal benefits of electricity generation–storage combinations with low energetic costs.
Ionic resistance is often a rate limiting factor in electrochemical systems such as batteries, supercapacitors, and ionic polymer actuators. Such cells typically contain laminated and interpenetrated structures consisting of one or two electronically conductive layers and an ionically conductive separator layer. Here we analyze the role of electrodes in determining ionic resistance, and study the effects of interpenetrating ionic and electronically conducting phases. We also show that conducting polymer electrodes that are polymerized on separator layers, as have been applied to create actuators, supercapacitors and electrochromic device, can be widely and unevenly distributed through the device. Swept sine and DC measurements are used with a four-point diffusion cell probe to characterize the phase dependent ionic impedances in 1. polypyrrole (PPy) coated polyvinylidene fluoride (PVDF) and 2. poly(ethylene dioxythiophene) (PEDOT) interpenetrated poly(ethylene oxide) (PEO) − nitrile butadiene rubber (NBR) co-polymer with various PEDOT content levels. A finite Warburg-based model is introduced to explain the frequency dependence, enabling a time constant for ion transport within membrane to be estimated. It is found that the separator layers in the composite membranes are shorted at higher frequencies (10∼100Hz). This effect is likely due to interpenetration of the electronic phases into the bulk of the separator layers, providing a means of reducing internal resistance and increase power at short times. Finally, a non-uniform impedance distribution model is introduced to predict the effective composite ionic conductivity in terms of the ionic conductivities of each phase, and their non-uniform volume fractions. Taken together, the approaches presented provide a means of probing the influence of ionic conductivities of various phases on the rate of charging in electrochemical devices.
A polymer-pyrolysis method was used to synthesize LiNi0.8Co0.2O2, which has potential application in lithium ion batteries. The effect of calcination temperature and time on the structure and electrochemical performance of the material was investigated. XRD analysis showed that the powders obtained by calcination at 750°C for 3h had the best-ordered hexagonal layer structure. SEM image showed these powders were fine, narrowly distributed with platelet morphology. The charge–discharge tests demonstrated these powders had the best electrochemical properties, with an initial discharge capacity of 189mAh/g and capacity retention of 95.2% after 50 cycles when cycled at 50mA/g between 3.0 and 4.3V. Besides, these powders also had exhibited excellent rate capability.
The effects of six types of aprotic organic solvents on the discharge performance and discharge products in Li-O2 batteries are systematically investigated. A large amount of Li2O2 is identified in the air electrodes discharged in glyme-based electrolytes, while only a small amount of Li2O2 is detected in the air electrodes discharged in the electrolytes of nitrile, ionic liquid, phosphate, and sulfoxide. Li2CO3 and LiF are also found as byproducts whose compositions are related to the solvents. Li2CO3 is produced from oxidation and decomposition of the solvent, not from the oxidation of the carbon-based air electrode, as revealed by using a 13C-labeled carbon electrode and the solid-state 13C-magic angle spinning nuclear magnetic resonance technique. LiF in the discharge products can be attributed to the attack of superoxide radical anions to the Teflon binder and/or the F-containing imide salt. The formation of these byproducts will significantly reduce the Coulombic efficiency and cycle life of the Li-air batteries. Among the studied solvents, dibutyl diglyme is the suitable solvent for Li-O2 batteries based on its overall properties. However, better electrolytes that can ensure the formation of Li2O2 but minimize other reaction products need to be further investigated for long cycling rechargeable Li-air batteries.
We report the synthesis of SnSb-based intermetallic with improved morphology. The electrochemical characterization shows that these materials have a good electrode behavior in a lithium cell. Capacities exceeding 800mAh/g with a charge–discharge efficiency approaching 100%, have been obtained. In addition, the percent of the initial irreversible capacity is moderate. The capacity decreases upon cycling quite likely due to a still not optimized electrode structure.
Silver antimonide, Ag3Sb, in which silver and antimony are both electrochemically active toward lithium, has been studied as an anode for lithium-ion batteries. The rate of capacity fade on cycling was monitored as a function of the voltage window, which has provided further information about the causes of capacity fade in intermetallic electrode systems. From the voltage profiles, and by comparison with the behavior of SnSb, InSb and Cu2Sb electrodes, the electrochemical reaction of Li/Ag3Sb cells was determined to take place in several discrete stages: first, by a displacement reaction in which lithium replaces Ag in the Ag3Sb structure in a two-step process between 0.9 and 0.7V to form Li3Sb via Li2AgSb; and second, by reaction of lithium with the extruded silver between 0.2 and 0.0V to form Li x Ag compounds (1≤x≤4). The rate of capacity fade that occurs when cells are cycled between 1.2 and 0.0V was significantly reduced by limiting the reaction to either: (1) the low voltage region (0.7–0.0V), which provided a stable capacity of ∼300mAh/g; or (2) to a wider operating window (1.2–0.1V, 250mAh/g), in which the formation of Li x Ag phases was suppressed.
The main challenge of applications of nickel metal hydride batteries in high power fields, new-energy vehicles, power tools, military devices, etc., originates from poor high-rate dischargeability of their negative electrode material—hydrogen storage alloys (HSAs). Here we report the design and synthesis of a composite by coating HSAs with reduced graphite oxide (RGO) via a top-down route. The capacity retention rate of the fabricated HSAs/RGO hybrid electrode reaches 51.25% at a discharge current density of 3000mAg−1, which is almost 4 times that of bare HSAs electrode (13.51%). Such an enhanced high-rate dischargeability performance is caused by (1) high specific surface area of RGO to increase active sites; (2) high conductivity of RGO to accelerate the charge transfer rate; and (3) unique interconnected RGO sheets among HSAs to reduce the internal resistance.
We present new evidence based on fMRI for the existence and neural architecture of an abstract supramodal language system that can integrate linguistic inputs arising from different modalities such that speech and print each activate a common code. Working with sentence material, our aim was to find out where the putative supramodal system is located and how it responds to comprehension challenges. To probe these questions we examined BOLD activity in experienced readers while they performed a semantic categorization task with matched written or spoken sentences that were either well-formed or contained anomalies of syntactic form or pragmatic content. On whole-brain scans, both anomalies increased net activity over non-anomalous baseline sentences, chiefly at left frontal and temporal regions of heteromodal cortex. The anomaly-sensitive sites correspond approximately to those that previous studies (Michael et al., 2001; Constable et al., 2004) have found to be sensitive to other differences in sentence complexity (object relative minus subject relative). Regions of interest (ROIs) were defined by peak response to anomaly averaging over modality conditions. Each anomaly-sensitive ROI showed the same pattern of response across sentence types in each modality. Voxel-by-voxel exploration over the whole brain based on a cosine similarity measure of common function confirmed the specificity of supramodal zones.
Potential and current density distributions were modelled and measured for an electrochemical cell with a bipolar electrode. The dimension of the bipolar electrode in the direction of current flow was extended, to enable experimental determination of the electrode potential and the local current densities at various positions inside the electrolyte and in the electrode body. The experimental results showed that the most active regions of the bipolar electrode are located at the ends of the bipolar electrode facing the terminal electrodes. The equations corresponding to the mathematical model of the experimental cell were solved using the finite volume method and gave very good qualitative agreement with the experimental data. However, some discrepancies between model predictions and experimental data were evident in the active parts of the bipolar electrode and in the variation of the terminal voltage with the total current. This was explained in terms of the active electrolyte cross-section and the electrode surface area being diminished due to the presence of gas bubbles in the system.
Advanced energy storage and power management systems designed through rigorous materials selection, testing and analysis processes are essential to ensuring mission longevity and success for space exploration applications. Comprehensive testing of Boston Power Swing 5300 lithium-ion (Li-ion) cells utilized by the National Aeronautics and Space Administration (NASA) to power humanoid robot Robonaut 2 (R2) is conducted to support the development of a test-correlated Thermal Desktop (TD) Systems Improved Numerical Differencing Analyzer (SINDA) (TD-S) model for evaluation of power system thermal performance. Temperature, current, working voltage and open circuit voltage measurements are taken during nominal charge–discharge operations to provide necessary characterization of the Swing 5300 cells for TD-S model correlation. Building from test data, embedded FORTRAN statements directly simulate Ohmic heat generation of the cells during charge–discharge as a function of surrounding temperature, local cell temperature and state of charge. The unique capability gained by using TD-S is demonstrated by simulating R2 battery thermal performance in example orbital environments for hypothetical extra-vehicular activities (EVA) exterior to a small satellite. Results provide necessary demonstration of this TD-S technique for thermo-electrochemical analysis of Li-ion cells operating in space environments.
A porous net-like β-Ni(OH)2/γ-NiOOH composite film is prepared by a chemical bath deposition. The as-prepared porous composite film shows a highly porous structure built up by many interconnected nanoflakes with a thickness of about 20nm. The pseudocapacitive behavior of the porous composite film is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge tests in 1M KOH. The porous β-Ni(OH)2/γ-NiOOH composite film exhibits a noticeable pseudocapacitance with 1420Fg−1 at 2Ag−1 and 1098Fg−1 at 40Ag−1, respectively, much higher than those of the dense Ni(OH)2 film (897Fg−1 at 2Ag−1 and 401 at 40Ag−1). The porous architecture is responsible for the enhancement of the electrochemical properties, and it increases electrochemical reaction area, shortens ions diffusion paths and relaxes volume change caused by the electrochemical reactions.
The effects of temporal data resolution on the interpretation of fish behaviours are questions fundamental to research programs using electronic tags with finite data storage and data transmission capacities. However, understanding these effects requires sub-sampling high-resolution data at multiple temporal resolutions. In pop-up satellite archival tags (PSATs), data transmissions via satellite are limited, so temporal resolution is a decreasing function of the deployment duration. Physical recovery of PSATs overcomes this limitation, providing data on temperature, depth, etc., at rates at least 15–30 times greater than transmitted data.
This paper reports the development and characterization of sulfonated polysulfone (SPSf) polymer electrolytes for direct methanol fuel cells. The synthesis of sulfonated polysulfone was performed by a post sulfonation method using trimethyl silyl chlorosulfonate as a mild sulfonating agent. Bare polysulfone membranes were prepared with two different sulfonation levels (60%, SPSf-60 and 70%, SPSf-70), whereas, a composite membrane of SPSf-60 was prepared with 5wt% silica filler. These membranes were investigated in direct methanol fuel cells (DMFCs) operating at low (30–40°C) and high temperatures (100–120°C). DMFC power densities were about 140mWcm−2 at 100°C with the bare SPSf-60 membrane and 180mWcm−2 at 120°C with the SPSf-60-SiO2 composite membrane. The best performance achieved at ambient temperature using a membrane with high degree of sulfonation (70%, SPSf-70) was 20mWcm−2 at atmospheric pressure. This makes the polysulfone-based DMFC suitable for application in portable devices.
Low- and middle-income countries often lack the fiscal, infrastructural and human resources to conduct evidence-based research; similar constraints may also hinder the application of good clinical practice guidelines based on research findings from high-income countries. While the context of health organizations is increasingly recognized as an important consideration when such guidelines are implemented, there is a paucity of studies that have considered local contexts of resource-scarcity against recommended clinical guidelines.
In-plane micro-supercapacitors (MSCs), as promising power candidates for micro-devices, typically exhibit high power densities, large charge/discharge rates, and long cycling lifetimes. The high areal/volumetric capacitances, high energy/power densities, high rate capability, as well as flexibility are the main scientific pursue in recent years. Among diverse electrode materials for MSCs, coordination polymer frameworks are emerging due to the designable porous structure and tunable functionality. However, the unsatisfied electrochemical performance still hinders their practical applications. In this work, we demonstrate the first time an efficient in-situ growth approach to precisely modify the vacancy of Prussian-blue nano-thin films with pyridine by coordination reaction for high energy-density MSCs. Confirmed by the experimental results and density functional theory calculation, the vacancy modification within Prussian-blue network improved the film-forming property, hydrophilicity, and electrochemical activity of the thin films. The resultant MSCs based on pyridine-modified Prussian-blue exhibited an ultrahigh energy density of up to 12.1 mWh cm−3 and an ultra-low time constant (τ0) of 0.038 ms, which are the best values among the state-of-the-art in-plane MSCs. This work provides an attractive solution for structural engineering of promising active materials on molecule level toward high-performance micro-energy devices.
The enhancement of the thermal storage capacity of a solar receiver using phase change materials (PCMs) to give inertial balance is experimentally investigated in this research study. A parabolic dish collector with a reflector aperture area of 16 m2 is used to test the performance of the solar receiver. Sugar alcohols are selected as phase change materials for their properties of medium melting point, high latent heat and medium phase change temperature. The PCMs are filled in the receiver as thin layers to capture the peak radiation and store the heat depending on the temperature distribution and collection efficiencies on the solar receiver. Outdoor tests are conducted at different flow rates of heat transfer fluid through the solar receiver. The PCM in the solar receiver ensures a uniform heat output during a short discontinuity of solar radiation due to the thermal buffering effect of the solar receiver. The average energy and exergy efficiencies of the receiver with multiple PCMs are 66.7% and 13.8%, respectively, for the HTF flow rate of 80 kg/h. The solar receiver acts as a thermal battery for meeting thermal needs even after sunset.
Graphite nanosheet anchored with nanocrystal manganese oxide (Mn3O4, MnO) was synthesized by a facile in situ one-pot solvothermal route. It was found that nanosized Mn3O4 and MnO particles (30–50nm) were homogeneously anchored on graphite nanosheet. During the hydrothermal reaction, the reduction of graphite oxide to graphite nanosheet and the formation of manganese oxide occur simultaneously, forming a manganese-oxide/graphite nanosheet sandwich structure. In this sandwich structure, the electrochemical properties of Mn3O4 and MnO can be obviously improved because of the buffering, confining and conducting effects of the graphite nanosheet. The good electrochemical performance of manganese-oxide/graphite nanosheet composites makes them potential application as anodes in Li-ion batteries.
The structure and electrochemical properties of LiMn1.5Ni0.5−x Co x O4 (0.0⩽ x ⩽0.5) cathodes for lithium ion batteries were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and galvanostatic charge–discharge tests. Cathode materials with different Co contents which were synthesized by a spray-drying method showed a single-phase spinel structure without any impurity. The XRD data reveal that the lattice parameter decreases and the structure stability is improved on increasing the amount of Co substitution. Cyclic voltammetric studies indicated three voltage regions of electrochemical activity, the three pairs of peaks related to the redox couples Mn3+/Mn4+, Ni2+/Ni4+ and Co3+/Co4+. The amount of Co doping induced a variation in the CV peak intensity and charge/discharge plateau length. Galvanostatic tests showed that with an increase in the value of x in the composition, the cycling stability was improved significantly at high temperature. For the LiMn1.5Ni1.4Co0.1O4, the initial capacity still had a high value of over 123mAhg−1, and after 20 cycles, it retained over 115mAhg−1 at 55°C. When the value of x is 0.4 or 0.5, after cycling, the capacity nearly did not nearly fade between 3.20 and 4.95V at 55°C.
The purpose of this study was to evaluate the functional status prior to and at different times after anterior cruciate ligament reconstruction (ACLR), and to analyze the changes in the kinetic patterns of the involved and uninvolved lower limb during gait, sprint and three hop tests.
As the preliminary step to elucidate the ion transfer mechanism of lithium (Li) species in the cathode electrode of glassy carbon material, molecular dynamics (MD) simulation was taken place describing the initial thermal movement of two Li atoms in the simulation time range of 10 ps maximally in the hydrogen terminated cluster model, C150H30, at molecular mechanics 2 (MM2) level. The formation of Li2 atom pair is specified in the central area of the cluster model as the result of the structural optimization. In the low temperature range from 4 to 10 K, accompanied by the rotational and stretching vibrational motions, it goes around the central area of the cluster model. Diffusion process of the atom pair is simulated dynamically for the first time in the present study. Decomposition of the atom pair occurred at 50 K and it produces two Li atoms which go and back independently from the center to the edge of the cluster model crossing the CC bonds orthogonally. Formation and diffusion processes of Li2 atom pair may be responsible for the charge–discharge cycles in the glassy carbon electrode in the lithium secondary battery.
Intentionally inducing worst-case thermal runaway scenarios in Li-ion cells on-demand is a definitive way to test the efficacy of battery systems in safely mitigating the consequences of catastrophic failure. An internal short-circuiting (ISC) device is implanted into three 18650 cell designs: one standard, one with a bottom vent, and one with a thicker casing. Through an extensive study of 228 cells, the position at which thermal runaway initiates is shown to greatly affect the tendency of cells to rupture and incur side-wall breaches at specific locations. The risks associated with each failure mechanism and position of the ISC device are quantified using a custom calorimeter that can decouple the heat from ejected and non-ejected contents. Causes of high-risk failure mechanisms, such as bursting and side-wall breaches, are elucidated using high-speed synchrotron X-ray imaging at 2000 frames per second and image-based 3D thermal runaway computational models, which together are used to construct a comprehensive description of external risks based on internal structural and thermal phenomena.