batterydata/paper-abstracts huggingface dataset:
A numerically efficient mathematical model of a proton exchange membrane fuel cell (PEMFC) stack is presented. The aim of this model is to study the dynamic response of a PEMFC stack subjected to load changes under the restriction of short computing time. This restriction was imposed in order for the model to be applicable for nonlinear model predictive control (NMPC). The dynamic, non-isothermal model is based on mass and energy balance equations, which are reduced to ordinary differential equations in time. The reduced equations are solved for a single cell and the results are upscaled to describe the fuel cell stack. This approach makes our calculations computationally efficient. We study the feasibility of capturing water balance effects with such a reduced model. Mass balance equations for water vapor and liquid water including the phase change as well as a steady-state membrane model accounting for the electro-osmotic drag and diffusion of water through the membrane are included. Based on this approach the model is successfully used to predict critical operating conditions by monitoring the amount of liquid water in the stack and the stack impedance. The model and the overall calculation method are validated using two different load profiles on realistic time scales of up to 30min. The simulation results are used to clarify the measured characteristics of the stack temperature and the stack voltage, which has rarely been done on such long time scales. In addition, a discussion of the influence of flooding and dry-out on the stack voltage is included. The modeling approach proves to be computationally efficient: an operating time of 0.5h is simulated in less than 1s, while still showing sufficient accuracy.
Studies have shown that drivers often spend over 20 min cruising for parking in city centers, accounting for as much as 30% of the traffic congestion. In response, cities like San Francisco have deployed systems capable of providing drivers real-time parking availability information. However, such systems rely on specialized infrastructure whose installation and maintenance costs in the tens of millions of dollars, unaffordable for many cities. We present SmartPark, a system for real-time parking information that relaxes the requirement for specialized infrastructure, relying instead on the smartphone’s sensors and the ubiquitous Wi-Fi and cellular infrastructure. To accomplish this, SmartPark addresses two major challenges, under the constraint of minimum impact on battery life: transportation mode detection and location matching. To minimize initial deployment cost and risk, SmartPark introduces an analytical approach for estimating parking availability even when only a small fraction of users adopt the application. We evaluate SmartPark using simulations and in the wild. Simulation results show that SmartPark, benefiting from as little as 20% adoption rate, can estimate parking availability with accuracy above 90%. Experimental results with the help of 12 volunteers show that SmartPark detects unparking events 97% of the time while triggering zero false positives.
We present a self-powered flexible printed circuit (FPC) board with an integrated zigzag-shaped triboelectric generator (TEG). This is the first time the fabrication of a TEG has been adapted for industrial production, making the fabrication procedure efficient and low-cost. Multiple friction pairs were integrated in a single TEG cell. The TEG with 10 integrated friction pairs has achieved a voltage of about 620V with a current density of 45.1μA/cm2. Continuous periodic output was generated under periodic impacts under frequencies ranging from 2Hz to 15Hz. Most importantly, the FPC technology makes it simple to integrate electronic components with the TEG to form a self-powered system. As an example, 100 LEDs mounted on the FPC board can be directly illuminated by finger pressing.
Redox flow batteries (RFBs) are rugged systems, which can withstand several thousand cycles and last many years. However, they suffer from low energy density, low power density, and low efficiency. Integrating a Thermally Regenerative Electrochemical Cycle (TREC) into the RFB, it is possible to mitigate some of these drawbacks. The TREC takes advantage of the temperature dependence of the cell voltage to convert heat directly into electrical energy. Here, the performance increase of a TREC-RFB is investigated using two kinds of all-vanadium electrolyte chemistries: one containing a typical concentration of sulfuric acid and one containing a large excess of hydrochloric acid. The results show that the energy density of the system was increased by 1.3Wh L−1 and 0.8Wh L−1, respectively and the overall energy efficiency also increased by 9 and 5 percentage points, respectively. The integration of the heat exchangers necessary to change the battery temperature is readily facilitated by the design of the redox flow battery, which already utilizes fluid circulation loops.
A method is proposed for the characterisation of expander materials based on the comparison of the results of three different electrochemical techniques: electrochemical impedance, cyclic voltammetry and potentiostatic transients. The evaluation of the expanders performance carried out on the basis of the results of such techniques takes into account different important actions of the organic additives such as adsorption on lead and the kinetics of electrochemical reactions, which are all very important for the practical behaviour of the expanders in the negative plate of the lead–acid battery. The need of clarifying possible correlations between chemical characterisation and electrochemical tests is shortly discussed. This last point is mainly focused on the understanding of the action of the functional groups which are present in the organic molecules.
Lithium ion capacitors (LICs) were assembled using pre-lithiated graphite anode and activated carbon (AC) cathode. The cells were tested for their rate capability at 1C and 10C for 100 and 600cycles, respectively at two different cut-off voltages. The cell delivered a discharge energy density of 55Whkg−1 (active materials basis) over the potential range of 3.1–4.1V and 100Whkg−1 in the extended cut-off potential of 2.0–4.1V. The maximum energy density obtained with LIC is about 8 times higher than the energy density obtainable with conventional EDLCs that operates in a voltage window of 0.0–2.5V. The capacity fade of LIC with cycling is directly correlated with the reduced utilisation of the positive AC material during the charge storage process, which in turn, is caused by the instability of the pre-lithiated graphite negative electrode. The instability of the pre-lithiated graphite electrode resulted in the self-discharge of pre-doped Li, which is believed to be the result of a poorly formed solid electrolyte interface (SEI) on graphite surface. Li pre-doping methodology is shown to play a crucial role and contributes to the stability of the negative electrode and consequently the cell cycling stability.
Lithium magnesium silicate (LMS) exhibits strong adsorbability, cohesiveness, suspensibility, chemical stability and good cation exchangeability, which was chosen in this work to modify Li2ZnTi3O8 (LZTO) by simply mixing LZTO in LMS colloidal solution, followed by sintering at 750 °C for 5 h. The uniform LMS coating on LZTO particles gives rise to the marked enhancement in electrochemical performance of LZTO. The LMS-coated LZTO with a LMS/LZTO mass ratio of 0.015 achieves a high reversible capacity of 236.3 mAh g−1 at 100 mA g−1, which also demonstrates outstanding rate performance, attaining capacities of 243.3, 217.2, 200.5, 183.5, 140.4 and 269.8 mAh g−1 at the current rates of 100, 200, 400, 800, 1600 and 100 mA g−1. The appreciable performance is attributable to the uniform LMS coating for protecting LZTO against the direct contact with the electrolyte to refrain from the side reactions, enhancing the Coulombic efficiency in the initial cycle, improving electronic and ionic conductivities to weaken polarization by the interaction between LMS and electrolyte.
Publisher Summary Volcanoes are responsible for the formation of much of the Earth's surface. The origin of the word can be traced back to the Island of Vulcano, near Sicily. It was named after Vulcanus, the Roman god of fire and the forge. Volcanoes are one of the most powerful and destructive forces on the planet. They threaten those residing many miles around their immediate vicinity with massive destruction from pyroclastic flows, ballistic projection of materials, thermal injuries from volcanic emissions, and subsequent mud flows and ash fall. Fortunately, volcanologists have made substantial advancements in understanding and predicting eruptions. These advances have saved thousands of lives in recent eruptions and will save many more in the future. The best way to reduce volcano-related morbidity and mortality is simply educating the public of the importance of following the volcanologist's warnings and the emergency management official's recommendations. For those that do not or cannot evacuate, avoiding low-lying areas, reducing exposure to the ash, and making sure accumulations do not lead to structural failure, are the most important protective measures. Community preparedness should also focus on assisting vulnerable populations in preparing in advance and taking appropriate actions when eruptions threaten.
Layered-layered yolk-shell powders with composition 0.6Li(Li1/3Mn2/3)O2· 0.4Li(Ni1/3Co1/3Mn1/3)O2 are prepared by spray pyrolysis. Metal oxides-carbon composite powders are first formed as an intermediate product near the reactor entrance by drying and decomposition of droplets. Combustion, contraction, and recombustion processes of intermediate product produce yolk-shell-structured powders. The yolk-shell structure of the powders prepared directly by spray pyrolysis is maintained even after post-treatment at 800°C; this treatment temperature yields the best electrochemical performance. The composition of the powders post-treated at 800°C is Li1.12Ni0.14Co0.14Mn0.59O2. Mean grain sizes of the yolk-shell 0.6Li(Li1/3Mn2/3)O2·0.4Li(Ni1/3Co1/3Mn1/3)O2 powders, post-treated at 700, 750, and 800°C, measured from high resolution TEM images, are 47, 54, and 79nm, respectively, and their BET surface areas are 14, 9, and 7 m2 g−1. The initial discharge capacities of the powders, post-treated at the above temperatures, are 188, 280, and 239mA h g−1, respectively, and their initial Coulombic efficiencies are 87, 80, and 78%. Discharge capacities after 50 cycles of the post-treated powders are 81, 194, and 183mA h g−1, respectively, and the corresponding capacity retentions are 43, 70, and 77%.
The movement ecology of mutton snapper Lutjanus analis is poorly understood despite their ecological and economic importance in the Caribbean. Passive acoustic telemetry was used to determine home ranges of six adult L. analis, including diel patterns, in Brewers Bay, St. Thomas, US Virgin Islands. Understanding long-term space use, including site fidelity and habitat usage, is necessary to implement effective and appropriate management actions for a species with extensive space and resource needs.
Mixtures of alkylcarbonate electrolytes with an ionic liquid (IL) and a lithium salt have been studied in order to develop new electrolytes for lithium-ion cells with enhanced safety profiles. In this work the influence of the addition of N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Py14TFSI) on the electrochemical properties of commercial carbonate-based electrolytes, i.e. 1 M LiPF6 in EC:DMC (LP30) and in EC:DMC:DEC (LP71) is reported. Four new electrolyte compositions have been prepared and characterized. The addition of the ionic liquid in the electrolyte carbonate-based solution results in (i) an ionic conductivity comparable with that of the pristine IL-free carbonate-based electrolyte, (ii) the enlargement of the electrochemical stability window, and (iii) a large reduction of the self-extinguish time (SET) of the electrolyte mixture when exposed to a free flame. All the newly developed electrolytes have been tested in lithium cells versus LiFePO4 and Li4Ti5O12 electrodes: the cells show good performances in galvanostatic cycling. The best performing electrolyte i.e. LP30/Py14TFSI 70/30 wt/wt has been also successfully tested in a full Li-ion cell realized by coupling LiFePO4 and Li4Ti5O12 electrodes.
Sodium-ion hybrid capacitors (NIHC) with sodium ion battery type anodes and supercapacitor type cathodes are emerging as an attractive energy storage device due to the integration of high energy, high power and long lifetime. However, the battery type electrodes usually exhibit sluggish reaction kinetics than capacitor type cathodes due to slow Na ion insertion and extraction, which greatly hinders the rate performance. In this paper, carbon coated MoS2 nanosheets are vertically grown on carbon cloth (CC) substrate using a hydrothermal reaction followed by calcination. The expanded interlayer distance of the MoS2 ensures high ionic mobility while the highly conductive CC not only provides a self-supporting structure without the addition of insulative binder and additional conductive additive, but also effectively prevents the restacking of the MoS2 sheets during cycling. Thus the architecture delivers a high area capacity of 0.511 mAh cm−2 at a current density of 0.2 mA cm−2 and a stable capacity retention of 83.3% after 200 cycles at 1 mA cm−2. Furthermore, NIHC constructed with above anode delivers a high areal energy density of 1.22 mWh cm−2 at a power of 0.76 mW cm−2, demonstrating an excellent energy-power delivery.
Charge and discharge properties of spinel LiNi0.5Mn1.5O4 positive electrodes were investigated using propylene carbonate (PC)-based concentrated electrolyte solutions in the range of 0.83 (ca. 1moldm−3) to 4.45 (nearly saturated) molkg−1. The solvation state of PC in the concentrated electrolyte solution was studied by Raman spectroscopy. The HOMO energy of PC in Li+(PC) n was evaluated by first-principle calculation to assess the oxidative stability of PC molecules solvating lithium ion. Charge and discharge measurements revealed that the irreversible capacity due to solvent decomposition decreased with increasing the concentration of LiPF6, while discharge capacity increased. In addition, cycle performance of LiNi0.5Mn1.5O4 positive electrodes was remarkably improved by the use of graphitized Ketjenblack as a conductive additive.
Graphene-based nanomaterials (GBNMs) are widely used in various industrial and biomedical applications. GBNMs of different compositions, size and shapes are being introduced without thorough toxicity evaluation due to the unavailability of regulatory guidelines. Computational toxicity prediction methods are used by regulatory bodies to quickly assess health hazards caused by newer materials. Due to increasing demand of GBNMs in various size and functional groups in industrial and consumer based applications, rapid and reliable computational toxicity assessment methods are urgently needed. In the present work, we investigate the impact of graphene and graphene oxide nanomaterials on the structural conformations of small hepcidin peptide and compare the materials for their structural and conformational changes. Our molecular dynamics simulation studies revealed conformational changes in hepcidin due to its interaction with GBMNs, which results in a loss of its functional properties. Our results indicate that hepcidin peptide undergo severe structural deformations when superimposed on the graphene sheet in comparison to graphene oxide sheet. These observations suggest that graphene is more toxic than a graphene oxide nanosheet of similar area. Overall, this study indicates that computational methods based on structural deformation, using molecular dynamics (MD) simulations, can be used for the early evaluation of toxicity potential of novel nanomaterials.
The inverter-motor drive system is the main traction force in electric vehicles (EVs). The overall efficiency of inverter-motor will directly determine the energy consumption of EVs. In this paper, aiming at improving the overall efficiency of inverter-motor, a novel methodology is proposed. Firstly, the iron loss, copper loss and stray loss of motor, as well as the devices’ conduction loss and switching loss in inverter are modeled. Afterwards, based on previous loss model strategy and gold section search strategy, a novel hybrid efficiency-optimization control strategy is proposed. The proposed method combines each benefit in loss-model and gold section search, and can realize high efficiency operation of the inverter-motor system in large power range. Additionally, the proposed method manifests faster search speed and better accuracy compared to conventional methods. Experiment results validated the effectiveness of the proposed hybrid control strategy. Meanwhile, the impact of the efficiency improvement on the driving cycle is further investigated through Advanced Vehicle Simulator (ADVISOR) simulations.
This paper gives a comprehensive review about the most recent progress in synthesis, characterization, fundamental understanding, and the performance of graphene and graphene oxide sponges. Practical applications are considered including use in composite materials, as the electrode materials for electrochemical sensors, as absorbers for both gases and liquids, and as electrode materials for devices involved in electrochemical energy storage and conversion. Several advantages of both graphene and graphene oxide sponges such as three dimensional graphene networks, high surface area, high electro/thermo conductivities, high chemical/electrochemical stability, high flexibility and elasticity, and extremely high surface hydrophobicity are emphasized. To facilitate further research and development, the technical challenges are discussed, and several future research directions are also suggested in this paper.
Batteries employing lithium chemistry have been intensively investigated because of their high energy attributes which may be deployed for vehicle electrification and large-scale energy storage applications. Another important direction of battery research for micro-electronics, however, is relatively less discussed in the field but growing fast in recent years. This paper reviews chemistry and electrochemistry in different microbatteries along with their cell designs to meet the goals of their various applications. The state-of-the-art knowledge and recent progress of microbatteries for emerging micro-electronic devices may shed light on the future development of microbatteries towards high energy density and flexible design.
A simple method is described for the synthesis of graphene-silver nanoparticle hybrids from graphite and silver precursors using microwave spark ignition process. Adding ecofriendly free radical initiators, in the presence of hydrogen peroxide solution leads to the expansion of graphite to graphene nanosheets. Simultaneously, silver ions intercalated between the graphene layers are reduced to silver nanocrystals leading to the development of graphene-silver nanoparticle hybrids. Transmission electron microscopic (TEM) studies reveal the successful formation of graphene-silver nanoparticle hybrids. X-ray diffraction (XRD) shows that the silver nanoparticles formed on the graphene surfaces are face centered cubic crystals. The surface composition and functional groups present on the graphene-silver nanoparticle hybrids are corroborated using X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR). The lithium storage capacity of the synthesized material, when used as an anode material for rechargeable lithium secondary batteries is investigated. Its first specific discharge capacity is observed to be 580mAhg−1 and this has been increased to 827mAhg−1, by incorporating the silver nanoparticles between the graphene platelets. The reversible capacity of the graphene-silver nanoparticle hybrids is observed to be 714mAhg−1, which is significantly higher compared to that of graphene (420mAhg−1) prepared by the same process.
We investigated the usefulness of the Seizures and Epilepsy Education (SEE) program in improving quality of life, management of the seizure condition, and health care utilization in families having a child with epilepsy. Members of 15 families attended the program, with at least one parent from each family represented. Children attended if they were at least 12 years of age. Participants completed research instruments prior to attending the SEE program, and also 1 and 6 months after attendance. Both parents and children reported improvement in quality of life relating to child mental health after attending the SEE program. Parents reported reduced emotional impact of the child’s condition, fewer worries, and greater knowledge related to epilepsy. Results suggest that attending the SEE program may be beneficial to families having a child with epilepsy; however, further study is needed with a more robust research design.
Staging is a characteristic phenomena observed in intercalation electrodes. During staging process the equilibrium potential of the electrode exhibits weak dependence on the solid phase Li concentration and does not follow the classical Nernst behavior. The coexistence of structurally different solid phases results in multiple plateaus in the equilibrium potential curve. Such complexities make the thermodynamic description of equilibrium potential as a function of concentration difficult, and so it is usually represented through an empirical expression. The objective of this work is to develop a frame work based on thermodynamic principles to describe the equilibrium potential of intercalation electrodes. Redlich-Kister thermodynamic equation was used to describe the excess Gibbs free energy, which in turn was used to evaluate the equilibrium potential as a function of concentration. The equilibrium potential expression for different lithium intercalation electrodes such as LiCoO2, LiNi0.8Co0.15Al0.05O2, graphite and hard carbon were developed based on Redlich-Kister equation. The thermodynamic model was also used to estimate the activity of species directly from excess Gibbs free energy. The developed thermodynamic expressions along with the activity correction are incorporated into a single particle diffusion model for a Li-ion cell consisting of a graphite and LiCoO2 electrode. The interactions between the Li-ions during intercalation/deintercalation process were incorporated into the present model by considering the chemical potential gradient corrected for activity as the driving force. The effect of inclusion of activity correction in the single particle model was studied for different discharge rates. It was observed that the activity correction term yielded increased capacity especially at higher rates. The effect of activity correction term was also found to be more significant in the LiCoO2 electrode compared to the carbon electrode.
Lithium metal is used as an anode material in a 3.0V-class film-type MnO2||Li primary battery to increase the operating voltage and discharge capacity for application to active sensor tags of a radio-frequency identification system. A 20-μm thick lithium layer deposited homogeneously on a copper foil is prepared for the purpose of controlling the efficient utilization and lithium handling. A plasticized gel polymer electrolyte filled with SiO2 particles is also used to enhance the electrochemical stability and safety of the battery. A lithium primary battery with a lithium anode and a nonaqueous electrolyte is fabricated for the first time in the form of a film with a newly designed Nylon 6/Al/polypropylene pouch for perfect shielding. The fabricated 3.0V-class film-type lithium primary battery passes several safety tests and achieves a discharge capacity and an energy density of more than 9mAhcm−2 and 470WhL−1, respectively.