batterydata/paper-abstracts huggingface dataset:
Ad hoc networks consist of wireless hosts that communicate with each other in the absence of a fixed infrastructure. Such networks cannot rely on centralized and organized network management. The clustering problem consists of partitioning network nodes into non-overlapping groups called clusters. Clusters give a hierarchical organization to the network that facilitates network management and that increases its scalability. In a weight-based clustering algorithm, the clusterheads are selected according to their weight (a node’s parameter). The higher the weight of a node, the more suitable this node is for the role of clusterhead. In ad hoc networks, the amount of bandwidth, memory space or battery power of a node could be used to determine weight values. A self-stabilizing algorithm, regardless of the initial system configuration, converges to legitimate configurations without external intervention. Due to this property, self-stabilizing algorithms tolerate transient faults and they are adaptive to any topology change. In this paper, we present a robust self-stabilizing weight-based clustering algorithm for ad hoc networks. The robustness property guarantees that, starting from an arbitrary configuration, after one asynchronous round, the network is partitioned into clusters. After that, the network stays partitioned during the convergence phase toward a legitimate configuration where the clusters verify the “ad hoc clustering properties”.
The hybrid pulse power characteristics (HPPC) of Li(Ni0.8Co0.15Al0.05)O2 and Li1.1(Ni1/3Co1/3Mn1/3)0.9O2 electrode materials have been evaluated according to the FreedomCAR test manual and found to meet the power requirements for HEV applications. In addition to its excellent power capability, Li1.1(Ni1/3Co1/3Mn1/3)0.9O2 electrode material has shown much better safety characteristics than the Li(Ni0.8Co0.15Al0.05)O2 electrode material. To investigate the reason for this finding, Li(Ni0.8Co0.15Al0.05)O2 and Li1.1(Ni1/3Co1/3Mn1/3)0.9O2 powders were chemically delithiated using NO2BF4 oxidizer in an acetonitrile medium. The thermal gravimetric results show that both Li0.45(Ni0.8Co0.15Al0.05)O2 and Li0.55(Ni1/3Co1/3Mn1/3)O2 obtained powders release oxygen starting from 190 and 250°C with an overall oxygen loss of 11 and 6wt% at 600°C, respectively. The reactivity of the delithiated powders with several electrolytes was studied by differential scanning calorimetry (DSC) and accelerated rate calorimetry (ARC) techniques. The relationship between the safety characteristics of Li0.45(Ni0.8Co0.15Al0.05)O2 and Li0.55(Ni1/3Co1/3Mn1/3)O2 powders and their thermal stability was discussed in light of their structural rearrangement during thermal heating.
Lithium-ion batteries are the main energy storage unit for electric vehicles. The prevention of thermal runaway is essential for ensuring safe operation of these batteries. Different cell packaging patterns have an influence on the thermal runaway behavior of lithium-ion batteries during overcharging. In this paper, prismatic and pouch lithium-ion battery cells with the same capacity and chemistries are used to experimentally investigate the internal failure mechanisms and associated external characteristics during overcharging. The entire overcharge process is divided into five stages according to the voltage and temperature curves. The results indicate that the pouch battery cell exhibits better thermal behavior characteristic and overcharge tolerance when compared to the prismatic battery cell in stages I to III. However, the prismatic battery cell has better thermal runaway buffering characteristic, smaller deformation and longer early warning time. This is due to the use of a safety valve which results in subsided damage caused by thermal runaway. Their maximum surface temperature differences increase linearly with the overcharge process, until thermal runaway occurs and rapid rise to the highest temperature point takes place. These results provide an insight into the safety and thermal management design of battery systems.
Monoclinic VO2 nanorod thin films were deposited on indium‑tin-oxide-coated glass substrates using radio-frequency reactive magnetron sputtering at a substrate temperature of 300°C and various O2 flow rates. The thin films were characterized via standard analysis techniques. The VO2 thin films exhibited a highly crystalline monoclinic phase with an indirect band gap of ~1.73eV. At optimized O2 flow rate (4sccm), the thin films was observed nanorod structures, exhibited a remarkable photocurrent of ~0.08mAcm−2 during photoelectrochemical water splitting in the visible region. Electrochemical performance tests of the nanorod films revealed a specific capacitance of ~486mFcm−2 at a scan rate of 10mVs−1. In addition, amperometric I–t curves showed that VO2 thin film electrodes were highly stable during the photo-oxidation process. The nanorod films also exhibited a good specific capacitance of ~120mFcm−2 after 5000cycles at a scan rate of 100mVs−1. The photocurrents during photoelectrochemical water splitting and the specific capacitance of VO2 thin films deposited at O2 flow rates of 2 and 6sccm were 0.06 and 0.07mAcm−2 and 398 and 37mFcm−2, respectively. The films deposited under Ar at 8sccm and O2 at 4sccm showed the highest photoelectrochemical water splitting performance and specific capacitance, owing mainly to their nanorod-like morphology.
Our previous study of La1−x Sr x MnO3±δ (LSM) infiltrated La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode suggests that a hybrid phase, La0.8Sr0.2Co0.17Mn0.83O3−δ (LSMCo), is associated with the observed enhancement in performance and stability of LSCF cathodes. Here we report the properties of LSMCo as a potential cathode for a solid oxide fuel cell (SOFC). The electrical conductivity of LSMCo varies from 118 to 166Scm−1 at 500–800°C. The interfacial polarization resistances of an LSMCo cathode on YSZ electrolyte are smaller than those of an LSM cathode at 600–800°C. The performance of a cell based on an LSMCo cathode is ∼34% higher than that based on an LSM cathode while maintaining comparable long-term stability, indicating that LSMCo is a promising cathode material for intermediate temperature SOFCs.
Formation processes. Processes of formation of the negative plates proceed in two stages. In first stage, PbO and basic lead sulfates are partly reduced to Pb, and partly react with H2SO4 to form PbSO4. The solution in the plate pores is neutral to alkaline. During the second formation stage, PbSO4 is reduced to Pb and the pore solution becomes acidic. Formation starts on the grid surface yielding a grey (Pb+PbSO4) zone. This zone then grows along the two surfaces of the plate. After covering the whole plate surface, the (Pb+PbSO4) zones grow towards the plate interior until the entire plate volume is formed. Structure of negative active material (NAM). The structure of the lead active material formed during the first stage comprises a network (skeleton) of bonded particles of irregular shape. During the second formation stage, small Pb crystals are formed on the skeleton surface. These crystals take part in the discharge process and build the energetic structure of NAM which determines the capacity of the plate. The ratio between the skeleton and energetic structures has an impact on the performance of the negative plates. Effect of expander on the formation processes and on NAM structure. Lignosulfonate contributes to the formation of the energetic structure of NAM built of small Pb particles providing high active mass surface. The size of the Pb particles depends on the type and amount of expander used. The stability of the energetic structure depends on the expander. At temperatures higher than 60oC, expanders disintegrate and the plates lose capacity.
Aqueous sodium-ion batteries are attractive battery alternatives for stationary energy storage due to their inherently low cost and high safety. The development of advanced electrode materials with excellent performance and low cost is crucial for the success of aqueous Na-ion batteries. Albeit the high capacity and stable cycling of the leading anode of NaTi2(PO4)3, the high price of titanium element and the low Na-insertion potential close to the hydrogen evolution reaction may plague its application. Here we introduced a NASICON-type Na3Fe2(PO4)3 as a promising anode alternative for aqueous Na-ion batteries. Synchrotron X-ray diffraction and spectroscopy confirm its phase and atomic structure. Electrochemical characterization and X-ray photoelectron spectroscopy reveal the reversible Na+ insertion in Na3Fe2(PO4)3 due to the Fe3+/Fe2+ redox couple, which renders a specific capacity of ∼60 mAh g−1 and excellent cycling of 1000 cycles at 10C rate. A Super high rate of 100C was also achieved for this anode with a capacity retention of 61% after 1000 cycles. In addition, the Na3Fe2(PO4)3 anode is paired with a Prussian white analogue of Na2Mn[Fe(CN)6] into a full cell, exhibiting promising cell performance and material sustainability. Our work underlines the importance of fabricating aqueous batteries on the basis of the Earth-abundant, cost-effective, and non-toxic elements.
This paper presents a methodology to minimize the total cost of buying power from different energy producers including renewable energy generations particularly within the context of a microgrid. The proposed idea is primarily based on the controlled operation of a battery energy storage system (BESS) in the presence of practical system constraints coupled with our proposed cost optimization algorithm. The complex optimization problem with constraints has been solved using the well-known concept of dynamic programming. The methodology has been assessed using actual power and price data from six different power generation sites and cost reduction has been calculated for a number of BESSs by varying their energy and power capacities. Twofold benefits of the proposed methodology lie in minimizing the total cost along with the constraint-based efficient operation of the BESS. Simulation results depict that the given power demand at a particular region can be fulfilled properly at all times using a BESS and multiple power generation.
Nano-sized 0.3Li2MnO3·0.7LiNi1/3Mn1/3Co1/3O2 as novel cathode material was synthesized by a hydrothermal process with carbon nanotubes as template. The resulting 0.3Li2MnO3·0.7LiNi1/3Mn1/3Co1/3O2 material showed excellent electrochemical performance, and the LR-1.0 sample had the best cycling stability and rate capability. When the LR-1.0 sample was tested as a cathode at 0.1 and 2.0 C, its initial discharge capacities can reach up to 267.0 and 146.6 mAh g−1, respectively. The discharge capacity retention of 93.3 % at 0.1 C can be achieved after 50 cycles. The electrochemical impedance spectroscopy measurement revealed that the charge transfer resistance was only 205.3 Ω. These results indicated that the 0.3Li2MnO3·0.7LiNi1/3Mn1/3Co1/3O2 prepared by this method was a new promising cathode material for lithium ion batteries.
Spinel lithium titanate, Li4Ti5O12 (LTO) is attracting much attention as an alternative material replacing carbon based anodes in lithium ion batteries, due to its high rate properties as well as its durability and safety. The coexistence of the two phases, spinel Li4Ti5O12 and rock salt Li7Ti5O12, during the charge–discharge reactions is the key issue for the understanding of reaction mechanism and the development of LTO electrodes with improved performance. However, the two-phase distribution morphology in real LTO electrodes has not yet been reported, due to the difficulty in identifying the Li-inserted Li7Ti5O12 phase with high resolutions. Thus we apply the scanning transmission electron microscopy with electron energy loss spectroscopy (STEM–EELS) using the latest equipment with high energy and spatial resolutions. We have successfully identified the presence of the Li7Ti5O12 phase in Li-inserted LTO secondary particles, by the EELS analysis of Li composition, Ti oxidation state, and local configurations around oxygen atoms, compared to the Li4Ti5O12 phase. We have also obtained the two-phase distribution image in 50% Li-inserted LTO secondary particles, where separate presence of both the phases is clearly revealed. This indicates the particle-by-particle reaction mechanism, where the rate determining process exists in the boundary between primary particles.
Batteries for stationary and automotive applications are required to provide extended cycle life and calendar life. Lithium–manganese oxides (LiMn2O4) with spinel structure and lithium–nickel–cobalt mixed oxides (LiNiCoO2) with layered structures have been extensively studied in the last few years for usage in high energy and high power batteries in order to replace lithium–cobalt oxide (LiCoO2) as cathode material in terms of cost, abundance and performance. In this paper, we summarize some basic mechanisms responsible for capacity fading under cycling and different storage conditions for both types of cathode materials. Lithium–nickel–cobalt mixed oxides show excellent storage stability in the discharged state and low metal solubility in the electrolyte. The cycling stability is mainly influenced by structural changes in the delithiated state and thermal instability arises from oxygen release at elevated temperatures in the charged state. Small amounts of aluminum and magnesium dopants stabilize the layered structure and increase cycling stability of lithium–nickel–cobalt oxide. Different mechanisms of capacity fading especially at higher temperatures are discussed for lithium–manganese oxide spinels. Capacity fading is highly dependent on cycling and storage conditions and caused by structural changes as well as by side reactions with electrolyte catalyzed by decomposition products of LiPF6 conducting salt and H2O impurities in the electrolyte.
The Schizophrenia International Research Society held its first scientific conference in Venice, Italy, June 21 to 25th, 2008. A wide range of controversial topics were presented in overlapping and plenary oral sessions. These included new genetic studies, controversies about early detection of schizophrenia and the prodrome, treatment issues, clinical characteristics, cognition, neuropathology and neurophysiology, other etiological considerations, substance abuse co-morbidity, and animal models for investigating disease etiology and for use as targets in drug studies. Young investigators in the field were awarded travel grants to participate in the congress and one of their roles was to summarize the oral sessions and subsequent discussions. The reports that follow are the culmination of this work produced by 30 young investigators who attended the congress. It is hoped that these summaries will be useful synopses of what actually occurred at the congress for those who did not attend each session or were unable to be present. The abstracts of all presentations, as submitted by the authors a few months prior, were previously published as supplement 2 to volume 102/1–3, June 2008.
Lithium metal with high theoretical capacity (3860 mAh/g) and low operational voltage (−3.04 V vs. standard hydrogen electrode) reflects to be one of the most high energy density anodes for energy storage devices. While, its high chemical activity to continuously react with electrolytes causing low coulombic efficiency and formation of lithium dendrites leading safety concern limits practical applications. To conquer these challenges, amorphous Li3PO4 thin films with thickness of 0–200 nm are directly coated on the surface of Li metal foil via magnetron sputtering. The as-prepared Li3PO4 has almost insulated property with electronic conductivity of 1.4 × 10−10 S/cm and ionic conductivity of 2.8 × 10−8 S/cm. The conformal coating layer Li3PO4 can successfully suppress the lithium dendrites growth and improve its life span. The remarkable improvements of the Li3PO4-coated Li electrodes are mainly attributed to high chemical stability as well as amorphous nature of Li3PO4, which leads layer-by-layer growth Li film rather than islands form dendrites.
Carbon spheres (CS) with submicron size have demonstrated great potential in both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), in virtue of their tunable microstructure, facile dispersion in slurry, enabling densely packing along with enough interspace for effective electrolyte transportation. However, the synthesis of monodisperse CS with both uniform size and excellent energy storage performance at high charge/discharge rates is still very challenging. Herein, a surfactant-assisted hydrothermal growth strategy is proposed to produce monodisperse CS. Moreover, an ammonia treatment is adopted to boost up its capacity especially at high current densities. As-synthesized N-doped carbon spheres (NCS) exhibit excellent lithium/sodium ions storage ability which delivers reversible capacities of 580 mAh g−1 and 270 mAh g−1 for LIBs and SIBs respectively at a current density of 20 mA g−1. Moreover, NCS can retain 194 mAh g−1 at 4 A g−1 for LIBs and 90 mAh g−1 at 5 A g−1 for SIBs. The improving rate capacities of NCS can be attributed to the short diffusion lengths of Li+ and Na+ ions of uniform submicron structure, as well as large specific surface area (SSA), additional active sites and good conductivity provided by ammonia treatment.
The large fluctuations observed in the daily solar radiation profiles affect highly the reliability of the PV system sizing. Increasing the reliability of the PV system requires higher installed peak power (P m) and larger battery storage capacity (C L). This leads to increased costs, and makes PV technology less competitive. This research paper presents a new stochastic simulation model for stand-alone PV systems, developed to determine the minimum installed P m and C L for the PV system to be energy independent. The stochastic simulation model developed, makes use of knowledge acquired from an in-depth statistical analysis of the solar radiation data for the site, and simulates the energy delivered, the excess energy burnt, the load profiles and the state of charge of the battery system for the month the sizing is applied, and the PV system performance for the entire year. The simulation model provides the user with values for the autonomy factor d, simulating PV performance in order to determine the minimum P m and C L depending on the requirements of the application, i.e. operation with critical or non-critical loads. The model makes use of NASA’s Surface meteorology and Solar Energy database for the years 1990–2004 for various cities in Europe with a different climate. The results obtained with this new methodology indicate a substantial reduction in installed peak power and battery capacity, both for critical and non-critical operation, when compared to conventional approaches applied in PV sizing.
One of the most challenging issues in developing supercapacitor and capacitive deionization (CDI) technologies is the rational design and synthesis of active electrode materials, with favorable morphologies, reasonable porous structure and high surface area. Recently, three-dimensional (3D) graphene frameworks (3DGF)-based hybrids have been considered as one of the most promising candidates for supercapacitor and CDI applications. By incorporating functional nanomaterials into 3DGF, the obtained 3DGF-based hybrids exhibited enhanced properties or unique character compared to 3DGF. Here we report novel hierarchical hybrids with microporous carbon spheres (MCS) decorated 3DGF (3DGF-MCS), which not only possesses a hierarchical porous structure, but also maintains favorable features for supercapacitor and CDI applications, such as a large surface area and good electrical conductivity. The results indicate that 3DGF-MCS with 10wt% MCS exhibits excellent electrochemical performances, including a superior specific capacitance of 288.77Fg⿿1, and an ultrahigh electrosorption capacity of 19.8mgg⿿1. The 3DGF-MCS should be promising electrode materials for highly efficient supercapacitor and CDI applications.
The LiFe0.92PO4 including Fe vacancy defects was prepared as performance-improved cathode material for lithium-ion battery by a carbothermal reduction method. A combination of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), electrochemical testing, and ﬁrst-principles calculations was used to determine and rationalize the physical and electrochemical characterizations of LiFe0.92PO4. The XRD, FTIR and XPS results indicated that Fe vacancy defects had been successfully incorporated into the parent olivine phase of LiFe0.92PO4 and did not affect its olivine lattice structure. Especially, the LiFe0.92PO4 sample exhibited a discharge capacity of 69.0 mAh g−1 at 10C and capacity retention ratio of 96% after 100 cycles at various rates, implying excellent rate capability and cycling stability. Moreover, the lithium ion migration channels, energy band structures, densities of states, and charge densities of LiFePO4 and LiFe0.92PO4 were investigated by first-principles calculations. The results suggest that the higher lithium ion conduction and electronic conductivity of LiFe0.92PO4 is attributed to Fe vacancy defects.
The fabrication of graphene oxide (GO) thin layer encapsulated SiO2 microspheres (SiO2@GO) were accomplished by sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO2 microspheres. Then, hierarchical mesoporous δ-MnO2 hollow microspheres (δ-MnO2 HMS) were prepared by hydrothermal treatment of SiO2@GO microspheres in the presence of KMnO4, followed by removal of the SiO2 inner core in another hydrothermal reaction. The synthesized δ-MnO2 HMS was systematically characterized and found to exhibit remarkable supercapacitive performances in a three-electrode setup with the highest specific capacitance of 216.4 F g−1 at the current density of 0.5 A g−1, satisfactory rate capability and outstanding cyclic performance with the capacitance retention of 91.2% after consecutive charge/discharge at the current density of 5 A g−1 for over 3000 cycles. Such electrochemical behaviors of δ-MnO2 HMS electrode in a three-electrode system outperform those of a number of MnO2-based electrodes reported previously. Furthermore, a symmetric supercapacitor device of δ-MnO2 HMS//δ-MnO2 HMS was assembled. It released the maximum specific capacitance of 58.8 F g−1 at the current density of 0.25 A g−1, possessed excellent rate capability and favorable cycling stability with the capacitance retention up to 86.4% after cycling at the current density of 3 A g−1 for 3000 cycles, and offered the highest energy density of 8.2 W h kg−1 at a power density of 125 W kg−1, which was superior to that of many existing MnO2-based symmetric and asymmetric supercapacitors. The impressive electrochemical properties of δ-MnO2 HMS make it a promising candidate for constructing high-performance energy storage devices.
In current work, the ionic transport limitations in the Li-ion battery liquid electrolyte with separator are studied by a finite element method. This theoretical approach is based on the Nernst–Planck equation. It is shown that instead of solving coupled PDE system for concentration and potential, it is sufficient to calculate only the concentration profile in a three-dimensional (3D) structure to obtain a full description of the diffusion–migration ionic transport in the electrolyte in the steady-state. Subsequently, the overpotential and electric field can be calculated by using the provided equations. It was found that diffusion and migration overpotentials are equal in the steady-state. Consequently, two algorithms exploiting electrolyte simulations are proposed and successfully used to calculate the limiting current for the simulated battery system. In the present study a single perforated layer of the separator is inserted into the electrolyte and the simulations are carried out by increasing the complexity of the membrane holes. The ionic transportation dependence on the pore shape was found to be local and limited by the spatial area around the perforated separator.