batterydata/paper-abstracts huggingface dataset:
The development of advanced and safe electrochemical supercapacitors or hybrid supercapacitors combining a battery electrode material such as graphite and a porous carbon electrode implies the use of new electrolytes containing a tetra-alkylammonium or lithium salt dissolved preferentially in a safe and environmentally friendly solvent such as alkylcarbonates. In those systems, the carbon porosity of the activated carbon electrode controls the electrochemical behavior of the whole device. In this work, it is demonstrated that electrolytes containing highly polarizing ions such as Li+ dissolved in polar solvents such as alkylcarbonates do not completely loss their solvation shell at the opposite of what is observed for poorly solvated cations like TEABF4. As a consequence, the optimal carbon pore size for obtaining the largest energy density, while keeping a high power density, is wider when strongly solvated cations, like Li+ are used than for conventional organic electrolytes using acetonitrile as solvent and TEA+ as salt cations. TEA+ cations are easily desolvated and hence are able to penetrate in small pores matching the dimensions of bare ions. The dissimilarity of behavior of alkylcarbonates and acetonitrile based electrolytes highlights the importance of ion–solvent interactions when searching the optimal porous texture for the electrode material.
Ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate) treated carbon nanotube (CNT) sponges were tested as a conductive matrix and polysulfide reservoir for the cathode of lithium–sulfur batteries. X-ray photoelectron spectroscopy results confirmed that this treatment doped fluorine and oxygen on the surface of the CNT, and experimental results showed that this treatment had significantly improved adsorption of polysulfides in the CNT sponge. As a result, this sponge cathode accommodated a remarkably high sulfur areal loading of 8 mg cm−2, showing a high areal capacity of 7.1 mAh cm−2 at the 100th cycle at an areal current density of 1.28 mA cm−2 with an average capacity fading of 0.048% per cycle. The adsorbing energy of Li2S6 on the F/O-doped carbon structure was calculated using the density functional theory, confirming that the doping made the polysulfide adsorption stable particularly due to fluorine. This study provides a useful approach of simultaneously introducing both fluorine and oxygen to carbon in order to significantly improve the polysulfide adsorption on the carbon cathode and thereby obtain high areal discharge capacity, which is much more important than specific discharge capacity for actual battery operation.
High quality poly(indole-5-carboxylic acid) (PICA) films were synthesized electrochemically by direct anodic oxidation of indole-5-carboxylic acid (ICA) in boron trifluoride diethyl etherate (BFEE) containing additional 80% diethyl ether (EE) (by volume). PICA films obtained from this medium showed good electrochemical behavior and good thermal stability with a conductivity of 10−2 Scm−1. The doping level of PICA increased during electrochemical growth processes. Dedoped PICA films were soluble in dimethyl sulfoxide (DMSO). The structure of the polymer were studied by UV–vis spectroscopy, FT-IR spectroscopy and 1H NMR spectroscopy, which indicated that the polymerization occurred at C(2) and C(3) position. Fluorescent spectral studies indicated that PICA was a good blue-light emitter.
A novel concept of fuel cells, i.e., bendable fuel cells, is proposed and demonstrated by the fabrication of on-chip fuel cells on cycloolefin polymer films. This approach overcomes the brittleness and cost problems, i.e., a troubling aspect of miniaturized devices, of on-chip fuel cells.
A novel fabrication technique for micro proton exchange membrane fuel cells (μPEMFCs) based on carbon-MEMS (C-MEMS) was optimized to yield higher performance cells. Polymer manufacturing is relatively easy compared to directly patterning graphite as is typically done to make fuel cell bipolar plates. In a C-MEMS approach, fuel cell bipolar plates are fabricated by first patterning polymer Cirlex® sheets. By subsequently pyrolyzing the machined polymer sheets at high temperature in an inert atmosphere, carbon bipolar plates with intricate groove structures to distribute the reactants are obtained. Using an improved assembly technique such as polishing the carbonized plates to minimize the contact resistance between gas diffusion layers (GDL) and bipolar plates, better pyrolysis temperature control and a better end plate design, a μPEMFC with a 0.64cm2 active surface was fabricated using the newly developed bipolar plates. At 1atm and 25°C a maximum power density of ∼76mWcm−2 was obtained, and at 2atm and 25°C ∼85mWcm−2 was achieved. These data are comparable with data reported in the literature for μPEMFCs and are a dramatic improvement over earlier results reported for the same C-MEMS based fuel cell. Electrochemical Impedance Spectroscopy (EIS) and cyclic voltammetry were carried out to characterize steady-state and transient characteristics of the novel C-MEMS fuel cell.
SrLi2Ti6O14 has been prepared by using mesoporous TiO2 brookite as a template and reactant. The prepared particles retained the rounded shape of the precursor, leading to high dispersivity and high packing density. The material has been further electrochemically characterized in both half and full cells. It shows good cycling stability and rate capability. A 2.7-V cell has been built by combining a SrLi2Ti6O14 anode with a 4-V spinel cathode of LiMn2O4. This cell has a higher voltage compared to the 2.5-V LiMn2O4/Li4Ti5O12 system.
Polyaniline/graphene nanocomposites with microspherical morphology and porous structure are prepared as electrode materials for supercapacitors. Using few-layer graphene obtained by liquid phase exfoliation of graphite as the raw material, porous graphene microspheres are produced by spray drying, and are then employed as the substrates for the growth of polyaniline nanowire arrays by in situ polymerization. In the composite, interconnected graphene sheets with few structural defects constitute a high-efficient conductive network to improve the electrical conductivity of polyaniline. Furthermore, the microspherical architecture prevents restacking of polyaniline/graphene composite nanosheets, thus facilitates fast diffusion of electrolytes. Consequently, the nanocomposite exhibits excellent electrochemical performance. A specific capacitance of 338 F g−1 is reached in 1 M H2SO4 at a scan rate of 20 mV s−1, and a high capacity retention rate of 87.4% after 10,000 cycles at a current density of 3 A g−1 can be achieved, which suggests that the polyaniline/graphene composite with such kind of 3D architecture is a promising electrode material for high-performance supercapacitors.
The study looked at the use of red lead in the manufacturing of valve regulated lead acid (VRLA) miners cap lamp (MCL) batteries that were made with either flat plate or tubular positive electrodes. A problem with using only grey oxide in the manufacture of thick flat plate or tubular electrodes is the poor conversion of the active material to the desired lead dioxide. The addition of red lead to the initial starting material improves the formation efficiency but is considerably more expensive thereby increasing the cost of manufacturing. The study showed that by carefully controlling the formation conditions in terms of the voltage and temperature of a battery, good capacity performance can be achieved for cells made with flat plate electrodes that contain up to 25% red lead. The small amount of red lead in the active cured material reduces the effect of electrode surface sulphate formation and allows the battery to achieve its rated capacity within the first few cycles. Batteries made with flat plate positive electrodes that contained more that 50% red lead showed good initial capacity but had poor structural active material bonding. The study showed that MCL batteries made with tubular positive electrodes that contained less than 75% red lead resulted in a poorly formed electrode with limited capacity utilization. Pickling and soaking times of the tubular electrodes should be kept at a minimum thereby allowing higher active material utilization during subsequent capacity cycling. The study further showed that it is beneficial to use higher formation rates in order to reduce manufacturing time and to improve the active material characteristics.
A novel chemical route for the preparation of titanium suboxides (Ti n O2n−1) with Magneli phase was developed. The ceramic powders were prepared from TiCl4 by complexation of Ti ions and successive decomposition of the complex to form an amorphous oxide. A high temperature reduction (1050°C) of the amorphous oxide was carried out by using diluted hydrogen. IrO2 electrocatalysts supported on Ti-suboxides were prepared by incipient wetness. The chemistry, morphology and structure of the materials were studied by TPR, XRF, XPS, BET, TEM and XRD. The electrochemical activity for oxygen evolution in a solid polymer electrolyte (SPE) electrolyser of IrO2 catalysts supported on a commercial titanium suboxide (Ebonex®) and Ti n O2n−1 prepared in-house was investigated by ac-impedance spectroscopy, linear sweep and cyclic voltammetry. The results showed proper electronic conductivity for both electrocatalysts and superior electrocatalytic activity of the catalyst based on the Ti-suboxides prepared in-house compared to the commercial support. In situ cyclic voltammetry and ac-impedance analyses showed larger voltammetric charge and double layer capacitance for the catalyst based on the Ti-suboxides prepared in-house with respect to the catalyst supported on Ebonex®. These results were attributed to the better dispersion and larger occurrence of active catalytic sites on the surface of the suboxide prepared in-house based anode compared to the anode based on the commercial support.
Background Although many studies have assessed cognitive functioning in first-episode schizophrenia (FESz), the pattern and severity of impairment across cognitive domains remain unclear. Moreover, few studies have directly compared the pattern of cognitive performance between FESz and chronic schizophrenia (CSz). In this study we examined the cognitive impairment profile in FESz using a standardized neurocognitive battery (MATRICS Consensus Cognitive Battery; MCCB). Methods MCCB data were compared from 105 FESz patients, 176 CSz patients and 300 non-psychiatric (NP) participants. Mixed model analysis evaluated group differences in MCCB profiles and relative strengths and weaknesses in the MCCB profiles of patients. Clinical implications of MCCB performance were also examined; we compared the proportion of participants from each group who exhibited clinically-significant global cognitive impairment based on the MCCB Overall Composite score. Results FESz and CSz showed impaired performance across all MCCB domains relative to NP. With the exception of relative preservation of working memory and social cognition in FESz, the MCCB domain scores were similar in FESz and CSz. The distribution of impairment on the Overall Composite score did not significantly differ between FESz and CSz; compared to NP, both patient groups were overrepresented in moderate and severe impairment categories. Conclusion The pattern, magnitude, and distribution of severity of impairment in FESz were similar to that observed in CSz. However, early in the illness, there may be relative sparing of working memory and social cognition.
This paper describes the synthesis and physicochemical properties of a new type of titania/graphene oxide (TA/GO) composite. Titania powder was synthesized via the sol–gel method, and its surface was functionalized with N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS) to increase its adhesion to graphene oxide. Transmission electron microscopy (TEM), non-invasive back scattering (NIBS), porous structure parameters (low-temperature nitrogen sorption), degree of modification of titania and TA/GO determined by Fourier-transform infrared spectroscopy (FT-IR), impedance analysis, charging/discharging and cyclic voltammetry were carried out. At a current density of 50 mA g−1, the good cyclability exhibited by the TA/GO anode can be readily retained at 370 mAh g−1 after 50 cycles, which is outstanding among the TiO2 composites reported in the literature.
An enhanced non-isothermal transient model for a metal-free quinone–bromide flow battery is developed. The graphite plate and channel are also included in the geometric model to represent an actual cell more accurately and increase the generality and usefulness. Rather than applying Darcy’s law typically used in a two-dimensional model to calculate the relation of velocity and pressure, we applied the Brinkman equation to handle the interface between the porous electrode and channel. The model includes a comprehensive description of energy transport and presents time-dependent characteristics of voltage and overpotential changes. The performance changes at different applied current density, temperature and flow rate values are also investigated. At a low applied current density, the flow rate has little effect on cell performance. The voltage and overpotential increase followed by a small increase with the increase in temperature. The current density distribution indicates the importance of cell structure optimization. The model is validated using data obtained from experiments in the literature. The model may be used to predict the cell performance and enable the development of a quinone–bromide flow battery.
Handling of varying energy sources and flexible connection to smart grids is a current challenge. Minimizing the overall monetary cost and maximizing the use of renewable energy sources are not the exclusive optimization goals, but also guaranteeing the thermal comfort is an important goal. This paper deals with a comprehensive approach of a mixed-integer quadratic-programming model predictive control scheme based on the thermal building model and the building energy management system. Calculating the global optima while handling continuous and binary constraints as well as variables and considering both the thermal and electrical part of a smart home are the key aspect of the proposed model predictive controller. By inclusion of disturbance forecasts, occupancy prediction, and individual user weights the control scheme is optimally suited for implementation in real buildings. Furthermore, the occupancy prediction in this research is based on an unsupervised method, which is useful for an effective implementation. This work demonstrates the optimal management of appliances such as heating, a battery storage, a freezer, a dishwasher, a photo-voltaic system, and the opportunities to buy from and sell to the smart grid. Optimal utilization of the building’s thermal storage capacity helps to minimize necessary battery capacity. Simulation results underline the efficient global optimization while demonstrating all proposed features of the complex control scheme.
Rechargeable batteries electrodes are mainly classical oxides with single structure, but their performance is insufficient to meet the growing energy storage needs of modern-society. Recently, composite-structure materials with great improvements in electrochemical performance have been developed. However, little research has been conducted on these materials with regard to adjusting their structures and further controlling their electrochemical performance. Herein, composite-structure Na2/3Ni1/3−xFexTi2/3O2 (0 ≤ x ≤ 1/3) electrodes for sodium-ion batteries were designed on the basis of results from in-situ high-temperature X-ray diffraction. Triphase compositions of P2-Na2/3Ni1/3Ti2/3O2, tunnel-Na2.65Ti3.35Fe0.65O9, and tunnel-NaFeTiO4 were prepared, and Na+ insertion/extraction in different structures was observed using in-situ electrochemical X-ray diffraction. An optimum electrode with 46% P2-structure presented the best comprehensive performance: 105mAhg−1 initial reversible capacity along with 86.5% capacity-retention after 1500 cycles. This work opens a new field for designing and adjusting composite electrodes for better electrochemical performance, not limited for sodium-ion batteries but also for other advanced battery-systems.
TiO2(B) has stimulated great interests in lithium storage owing to the highest Li-ion mobility and theoretical capacity among all TiO2 polymorphs. However, the low conductivity and metastability of TiO2(B) still impede its practical application in lithium-ion batteries (LIBs). In this context, the porous TiO2(B) nanosheets offering rich lithium-insertion channels are rational appeals to enhancing the transport kinetics. And the firm 1D TiO2 nanowire can serve as a crossgirder to string together these nanosheets, which improves the deformation resistance of TiO2(B) nanosheets during repeated lithiation/delithiation processes. Herein, the motivation was realized by constructing a bunchy hierarchical structure (TiO2(B)-BH) in a facile solvothermal process. As an anode material for LIBs, TiO2(B)-BH exhibits high reversible capacity, long-term cycling stability (186.6mAhg−1 at 1675mAg−1 after 1000 cycles) and desirable rate performance. The multiple TiO2(B) nanosheets stringed by 1D nanowire possess fast pseudocapacitive behaviour, effective pathway for ion/electron transfer and high structural stability, leading to the superior electrochemical performance of TiO2(B)-BH. This orderly integration strategy of nanosheets can be extendedly applied to the architectural construction of electrode materials for other energy devices.
To reduce irreversible capacity and improve cycle performance of tin used in lithium ion batteries, Sn–Ni alloy nanorod electrodes with different Sn/Ni ratios were prepared by an anodic aluminum oxide template-assisted electrodeposition method. The structural and electrochemical performance of the electrode were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, cyclic voltammetry, and galvanostatic charge–discharge cycling measurement. The results showed that the copper substrate is covered with uniformly distributed Sn–Ni alloy nanorods with an average diameter of 250 nm. Different phases (Sn, Ni3Sn4 and metastable phases) of alloy nanorod formed in the electrodeposition baths with different compositions of Sn2+ and Ni2+ ions. Sn–Ni alloy nanorod electrode delivered excellent capacity retention and rate performance.
Lithium titanium oxyphosphate LiTiOPO4 is synthesized by a solution route and modified with a carbon layer using polyvinylidene difluoride as carbon source. It is demonstrated that the performance of LiTiOPO4 strongly depends on cycling potential range. In the potential range from 0.5 to 3.0V, limited capacity (less than 161mA h g−1) is obtained, which is ascribed to a mechanism involving the insertion of lithium ions into vacant sites of crystalline structure. As the cut-off potential is set down to 0.1V, a conversion of LiTiOPO4 occurs in the initial cycle, as a result, a relative high and reversible capacity of 285mAhg−1 at the current rate of 0.1C can be achieved during the subsequent cycles. However, resembling that of transition metal oxides, possible charging/discharging mechanism, in this case, may involve the formation and decomposition of Li2O formed in the conversion of LiTiOPO4. The new strategy also enables LiTiOPO4 as the electrode material with superior cycleability and rate capability of 195mA h g−1 at the current rate of 2.0C. The results indicate that carbon-coated LiTiOPO4 could be a promising anode material with relative high capacity and good rate capability for lithium ion batteries.
Low-cost sorbitanlaurat is used as new carbon source to synthesize Li2FeSiO4/C by sol–gel method. Four Li2FeSiO4/C products with different carbon contents are pursued as the cathode material of lithium-ion battery. The structures and morphologies of these products are characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope. The particle size of these Li2FeSiO4 products is about 10–20nm. The product with 8.4wt% carbon delivers an initial discharge capacity of 187mAhg−1 at 0.1C. This product also exhibits good rate and cycle performances. By Raman spectroscopy, cyclic voltammogram and impedance spectroscopy, the factor which can affect the rate performance of these Li2FeSiO4/C products is analyzed.
Expression of the Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis (Bt) Berliner strain PS149B1 in genetically modified maize (event DAS-59122-7) protects the crop from damage due to feeding by Diabrotica larvae including the western corn rootworm (Diabrotica virgifera virgifera). As part of the safety assessment of this maize, mammalian toxicology studies were conducted with heterologously produced Cry34Ab1 and Cry35Ab1 proteins. No evidence of acute toxicity was observed in mice following oral exposure to either the Cry34Ab1 or Cry35Ab1 proteins individually (2700 and 1850mg/kg, respectively) or concomitantly (482 and 1520mg/kg, respectively; 1:1 molar ratio). Similarly, no adverse effects were observed in mice in a repeated dose (28 day) dietary toxicity study that incorporated these proteins into diets at concentrations corresponding up to 1000-fold greater than the highest estimate of human exposure based on the concentrations of these proteins expressed in 59122 maize grain. These studies demonstrate that the Cry34Ab1 and Cry35Ab1 proteins do not represent a risk to human health and support previous studies indicating that 59122 maize grain is as safe and wholesome as non-GM maize grain.
The cycling performance of LiNi0.8Co0.1Mn0.1O2 cathode material has been enhanced by improvement nickel-rich material on surface oxygen-keeping capability. LiNi0.8Co0.1Mn0.1O2 cathode material with lower surface oxygen defects is synthesized via covering Ni0.8Co0.1Mn0.1(OH)2 with manganese acetate and sintering with LiOH·H2O at high temperature. A good layered structure with lower surface oxygen defects in the outer layer has been identified by XRD, FFT, HADDF-STEM and XPS. Compared with the bare material maintaining 77.2% capacity retention, the modified LiNi0.8Co0.1Mn0.1O2 materials Exhibit 90.4% capacity retention and 166 mAh·g−1 after 200 cycles at 1C rate. Electrochemical impedance spectroscopy, XRD and SEM of cycled electrodes tests results provide evidence that the improved cycling performance is mainly attributed to stable surface oxygen, the suppression of the interface reaction between the cathode and electrolyte and the improvement in the structural stability of material.
For wireless sensor networks (WSNs), uneven energy consumption is a major problem. A direct consequence of this is the energy hole problem, formation of sensing voids within the network field due to battery depleted sensors in the corresponding region. Hole formations are inherent in the network topology, yet it is possible to develop strategies to delay the hole formations to later stages of the network operation and essentially extend the network lifetime without sensing quality loss. In this work, we initially propose and analyze an approach that can be used to mitigate the hole problem. The approach is presented in detail and the effects on the sustained surveillance quality are presented. The results are based on simulations with different network configurations with realistic sensor models, MAC and routing protocols. By using the proposed approach, sustaining a sensing quality above a given threshold and more than doubling the network lifetime are possible. The results clearly indicate the suitability of the approach for especially demanding WSNs such as the ones used for border surveillance tasks.